Contemporary Evaluation of Tebipenem In Vitro Activity against Enterobacterales Clinical Isolates Causing Urinary Tract Infections in US Medical Centers (2019-2020)

Tebipenem pivoxil is an oral broad-spectrum carbapenem. This study evaluated the activity of tebipenem and comparators against UTI Enterobacterales from US hospitals (2019-2020). 3,576 Enterobacterales causing UTI in 52 centers in 9 US Census Divisions were included. Susceptibility testing followed the CLSI broth microdilution method. Escherichia coli, Klebsiella pneumoniae, and Proteus mirabilis with an MIC of ≥2 μg/mL for ceftazidime, ceftriaxone, and/or aztreonam were designated ESBL. Isolates were also grouped based on MDR phenotype. Tebipenem, meropenem, and ertapenem had MIC₉₀ against Enterobacterales of 0.06 μg/mL, 0.06 μg/mL and 0.03 μg/mL, respectively. Low susceptibility results for aztreonam (87.1% susceptible), cefazidime (88.1%), ceftriaxone (84.8%), and other agents were observed. Tebipenem and ertapenem were equally potent (MIC₉₀, 0.015 to 0.03 μg/mL) against E. coli and K. pneumoniae, whereas ertapenem showed an MIC 8-fold lower than tebipenem against P. mirabilis. Oral agents, such as amoxicillin-clavulanate, levofloxacin, and trimethoprim-sulfamethoxazole, showed elevated nonsusceptibility rates in the Middle Atlantic region (26, 45, 47, and 41%, respectively). ESBL prevalence varied from 7% to 16%, except in the Middle Atlantic region (42%). The carbapenems were active against ESBL and MDR isolates (93.7 to 96.8% susceptible). Elevated rates of ESBL in UTI pathogens in US hospitals were noted as well as a uniform in vitro potency (MIC₉₀) of tebipenem and the intravenous carbapenems, regardless of phenotype. IMPORTANCE The occurrence of urinary-tract Enterobacterales pathogens producing ESBL enzymes in community and nosocomial settings continues to increase, as does the coresistance to fluoroquinolones, trimethoprim-sulfamethoxazole and nitrofurantoin often exhibited by these pathogens. This scenario complicates the clinical empirical and guided management of UTI by precluding the use of oral and many intravenous options. Oral options appear compromised even among some ESBL-negative isolates, against which the use of parenteral agents may be required. In addition, the interregional variability of susceptibility results of US UTI pathogens provides a less predictable susceptibility pattern to inform empirical treatment decisions. This study evaluated the in vitro activity of tebipenem against contemporary uropathogens, including those resistant to currently available oral options.

124. Activity of Novel b-Lactam/b-Lactamase Inhibitor (BL/BLI) Combinations Against AmpC-Producing Species Collected in United States Hospitals

Background

Therapeutic options for Enterobacterales species known to overexpress chromosomal AmpC (AmpC producers) are limited since these organisms can develop resistance to BLs during therapy. Novel BL/BLIs, such as meropenem-vaborbactam (MEV), ceftazidime-avibactam (CZA), and imipenem-relebactam (IMR), display activity against isolates producing serine-carbapenemases, extended-spectrum β-lactamases, and AmpC enzymes. In this study, we evaluated the activity of novel BL/BLIs against a collection of AmpC producers collected in from US hospitals during 2021.

Activity of newer BL/BLI combinations against AmpC producers

Methods

A total of 1,252 AmpC producers including were consecutively collected in 31 US hospitals. Isolates were susceptibility tested by reference broth microdilution methods. CLSI breakpoints were applied.

Results

The activity of new BL/BLIs is summarized displayed in the Figure. MEV (MIC50/90, 0.03/0.06 mg/L) and amikacin were the most active agents tested against these isolates, inhibiting 99.8%. CZA (MIC50/90, 0.12/0.5 mg/L) inhibited 99.5%. IMR (MIC50/90, 0.12/1 mg/L) was active against 95.9%. Cefepime and meropenem were active against 92.0% and 97.6% of these isolates, respectively. Piperacillin-tazobactam and ceftolozane-tazobactam (MIC50/90, 0.5/8 mg/L) displayed activity against 76.4% and 83.6% of the AmpC producers, respectively. Tigecycline was active against 96.8% of the isolates; only 53.8% of the isolates had a colistin MIC of ≤2 mg/L. A total of 39 (3.2%) AmpC producers were nonsusceptible to imipenem and/or meropenem. MEV (MIC50/90, 0.25/2 mg/L) was active against 92.3%. IRL (MIC50/90, 0.25/2 mg/L) and CZA (MIC50/90, 1/ > 32 mg/L) were active against 89.7% of the carbapenem nonsusceptible AmpC producers. Against cefepime-resistant AmpC producers (n=45; 3.6%), MEV, IMR, and CZA had 93.3%, 88.9%, and 86.7% activity.

Conclusion

Infections caused by AmpC producers often are challenging to treat. Understanding the activity of new BL/BLIs is important as the use of cefepime and meropenem can also lead to resistance to these agents. MEV, IRL, and CZA displayed good activity against AmpC producers. When analyzing carbapenem-nonsusceptible or cefepime-resistant isolates, MEV was slightly more active but more potent than other BL/BLI combinations.

Disclosures

Mariana Castanheira, PhD, AbbVie: Grant/Research Support|Cidara: Grant/Research Support|GSK: Grant/Research Support|Melinta: Grant/Research Support|Pfizer: Grant/Research Support|Shionogi: Grant/Research Support Jennifer M. Streit, BS, MT(ASCP), Cidara: Grant/Research Support|GSK: Grant/Research Support|Melinta: Grant/Research Support|Shionogi: Grant/Research Support Cecilia G. Carvalhaes, MD, PhD, AbbVie: Grant/Research Support|Cidara: Grant/Research Support|Melinta: Grant/Research Support|Pfizer: Grant/Research Support Rodrigo E. Mendes, PhD, AbbVie: Grant/Research Support|Cidara: Grant/Research Support|GSK: Grant/Research Support|Melinta: Grant/Research Support|Nabriva Therapeutics: Grant/Research Support|Office for Assistant Secretary of Defense for Health Affairs: Grant/Research Support|Pfizer: Grant/Research Support|Shionogi: Grant/Research Support|Spero Therapeutics: Grant/Research Support Dee Shortridge, PhD, AbbVie: Grant/Research Support|JMI Laboratory: Employee|Melinta: Grant/Research Support|Menarini: Grant/Research Support|Shionogi: Grant/Research Support.

643. Cefiderocol In vitro Activity Against Molecularly Characterized Pseudomonas aeruginosa and Acinetobacter baumannii-calcoaceticus complex Clinical Isolates Causing Infection in United States Hospitals (2020-2021)

Background

Cefiderocol (CFDC) is a siderophore-conjugated cephalosporin with activity against Gram-negative bacteria. CFDC and comparator activities were analyzed against resistant and molecularly characterized P. aeruginosa (PSA) and A. baumannii-calcoaceticus complex (ACB) as part of the SENTRY Antimicrobial Surveillance Program.

Methods

2,241 PSA and 682 ACB were consecutively collected from 63 US sites in 2020-2021. Susceptibility testing was performed by broth microdilution and CFDC testing used iron-depleted media. FDA and CLSI breakpoints were used for CFDC. CLSI criteria were applied to comparators, except for imipenem-relebactam (IMR) that used FDA breakpoints. Isolates with a resistance phenotype to ≥ 3 classes were defined as multidrug resistant (MDR). ACB and PSA with imipenem and/or meropenem (MER) MIC ≥4 μg/mL or ceftazidime (CAZ) and/or cefepime MIC ≥ 16 μg/mL were subjected to next-generation genome sequencing for screening of acquired carbapenemase genes.

Results

31.6% (709/2,241) and 16.9% (379/2,241) of PSA met the MIC screening criteria and showed an MDR phenotype, respectively (Table). Carbapenemase genes were detected in 6 (< 1%) PSA. CFDC had similar MIC against PSA that did not (MIC_50/90, 0.06/0.25 μg/mL) and did (MIC_50/90, 0.12/0.5 μg/mL) meet the MIC screening criteria. CFDC also had similar MIC₅₀ values (0.12 μg/mL) against the MDR and carbapenemase-positive PSA populations, whereas other agents had compromised activity. 42.5% (290/682) of ACB met the MIC screening criteria, while 35.9% (245/682) had an MDR phenotype, and 27.3% carried carbapenemase genes (all OXA carbapenemase, except for 2 bla_NDM-1). In general, CFDC, IMR, meropenem-vaborbactam, MER, ceftazidime-avibactam, and CAZ had activity against ACB that did not meet the MIC screening criteria, but only CFDC (MIC_50/90, 0.25-0.5/2 μg/mL) was active against the resistant ACB subsets.

Conclusion

Many PSA showed a resistance phenotype but acquired carbapenemase genes remained rare in this subset. In contrast, resistance and presence of carbapenemase genes were high in ACB. CFDC showed potent activity against PSA and ACB subsets in US hospitals, including across resistant and molecularly characterized subsets, where treatment options were limited.

Disclosures

Rodrigo E. Mendes, PhD, AbbVie: Grant/Research Support|Cidara: Grant/Research Support|GSK: Grant/Research Support|Melinta: Grant/Research Support|Nabriva Therapeutics: Grant/Research Support|Office for Assistant Secretary of Defense for Health Affairs: Grant/Research Support|Pfizer: Grant/Research Support|Shionogi: Grant/Research Support|Spero Therapeutics: Grant/Research Support Cory Hubler, BS, Melinta: Grant/Research Support|Shionogi: Grant/Research Support Valerie Kantro, BA, AbbVie: Grant/Research Support|GSK: Grant/Research Support|Melinta: Grant/Research Support|Shionogi: Grant/Research Support Dee Shortridge, PhD, AbbVie: Grant/Research Support|JMI Laboratory: Employee|Melinta: Grant/Research Support|Menarini: Grant/Research Support|Shionogi: Grant/Research Support Helio S. Sader, MD, PhD, AbbVie: Grant/Research Support|Cidara: Grant/Research Support|Melinta: Grant/Research Support|Nabriva Therapeutics: Grant/Research Support|Pfizer: Grant/Research Support Jennifer M. Streit, BS, MT(ASCP), Cidara: Grant/Research Support|GSK: Grant/Research Support|Melinta: Grant/Research Support|Shionogi: Grant/Research Support Mariana Castanheira, PhD, AbbVie: Grant/Research Support|Cidara: Grant/Research Support|GSK: Grant/Research Support|Melinta: Grant/Research Support|Pfizer: Grant/Research Support|Shionogi: Grant/Research Support.

641. Activity of Gepotidacin Tested Against Molecularly Characterized Escherichia coli Isolates Resistant to Commonly Used Oral Therapies for UTI in the US (2019-2020)

Background

Gepotidacin is a novel first in class triazaacenaphthylene antibiotic in Phase 3 clinical trials for the treatment of gonorrhea and uncomplicated urinary tract infection (UTI). This study evaluates the epidemiology of E. coli (EC) causing UTI in US patients and the activity of gepotidacin and comparators against various subsets, including those with characterized resistance mechanisms.

Methods

1,993 EC collected from 45 US sites were included as part of the Gepotidacin UTI Global Surveillance Study as part of the SENTRY Antimicrobial Surveillance Program (2019-2020). Isolates were tested for susceptibility (S) by CLSI methods and CLSI interpretations were applied. Isolates that met MIC criteria for screening of extended-spectrum β-lactamase (ESBL) genes were subjected to genome sequencing followed by ESBL gene screening and epidemiology typing (MLST, O:H, and fimH).

Results

A total of 84.4% (1,682/1,993) EC were ESBL negative (Table). Among these isolates, 16.5% (278/1,682) were not S to the fluoroquinolones (FQ) ciprofloxacin and/or levofloxacin, whereas 26.2% (440/1,682) were not S to trimethoprim-sulfamethoxazole (SXT). An ESBL phenotype was noted in 15.6% (311/1,993) of EC, which tended to be mostly not S to the FQs (79.7%), SXT (61.7%), amoxicillin-clavulanate (52.9%), and oral cephalosporins (99.7%). Most ESBL isolates carried CTX-M alleles alone (81.4%; 253/311), whereas 9.6% (30/311) had plasmid AmpC genes. Approximately half (56.3%; 175/311) of ESBL isolates belonged to clonal complex (CC) 131, of which 70.9% (124/175) were O25b:H4 and carried fimH30. Overall, gepotidacin had MIC90 of 2-4 mg/L against various phenotypic/genotypic subsets.

Conclusion

High rates of EC not S to commonly used oral agents (FQs and SXT) were observed. ESBL phenotype further compromised the activity of oral agents, including oral cephalosporins. Gepotidacin had potent and stable in vitro activity against various subsets, including the resistant CC131 O25b:H4 clone. These data support the further clinical development of gepotidacin as a treatment option for UTI caused by EC, including resistant isolates against which other oral treatment options are limited.

Disclosures

Rodrigo E. Mendes, PhD, AbbVie: Grant/Research Support|Cidara: Grant/Research Support|GSK: Grant/Research Support|Melinta: Grant/Research Support|Nabriva Therapeutics: Grant/Research Support|Office for Assistant Secretary of Defense for Health Affairs: Grant/Research Support|Pfizer: Grant/Research Support|Shionogi: Grant/Research Support|Spero Therapeutics: Grant/Research Support SJ Ryan Arends, PhD, AbbVie: Grant/Research Support|GSK: Grant/Research Support|Nabriva Therapeutics: Grant/Research Support|Shionogi: Grant/Research Support John H. Kimbrough, PhD, AbbVie: Grant/Research Support|GSK: Grant/Research Support Valerie Kantro, BA, AbbVie: Grant/Research Support|GSK: Grant/Research Support|Melinta: Grant/Research Support|Shionogi: Grant/Research Support Nicole E. Scangarella-Oman, MS, GlaxoSmithKline plc.: Employee and shareholder Jennifer M. Streit, BS, MT(ASCP), Cidara: Grant/Research Support|GSK: Grant/Research Support|Melinta: Grant/Research Support|Shionogi: Grant/Research Support Mariana Castanheira, PhD, AbbVie: Grant/Research Support|Cidara: Grant/Research Support|GSK: Grant/Research Support|Melinta: Grant/Research Support|Pfizer: Grant/Research Support|Shionogi: Grant/Research Support.

2176. In Vitro Evaluation of Delafloxacin Activity Against Contemporary US Isolates from Cystic Fibrosis Patients Hospitalized with Pneumonia: Results from the SENTRY Antimicrobial Surveillance Program (2019-2021)

Background

Delafloxacin (DLX) is a broad-spectrum fluoroquinolone antibacterial approved in the US for the treatment of community-acquired bacterial pneumonia (CABP) and acute bacterial skin and skin structure infections. DLX is indicated to treat CABP caused by multiple pathogens, including methicillin-susceptible Staphylococcus aureus (MSSA) and Pseudomonas aeruginosa (PSA). S. aureus (SA) and PSA are common pathogens causing pneumonia in cystic fibrosis (CF) patients. In this study, the in vitro susceptibilities of DLX and comparator quinolones were determined for clinical isolates from US CF patients collected during 2019-2021.

Methods

Isolates from CF patients hospitalized with pneumonia were consecutively collected at 17 US medical centers participating in the SENTRY Surveillance Program. Sites submitted 1 isolate per patient per infection episode. Isolate identification was determined at each site and confirmed using MALDI-TOF at JMI Laboratories. Susceptibility testing was performed according to CLSI broth microdilution methodology. FDA interpretive criteria were used for DLX, and CLSI (2022) criteria were applied to comparators.

Results

A total of 115 SA, including 72 MSSA and 67 PSA, were submitted. Susceptibilities (%S) to DLX, levofloxacin (LEV), and moxifloxacin (MOX) for MSSA are shown in the table. As MOX does not have breakpoints for PSA, ciprofloxacin (CIP) was tested. Against all SA, %S was 73.9%, 67.0%, and 67.0% for DLX, LEV, and MOX, respectively. DLX had the highest %S against MSSA (94.4%). The %S to LEV and MOX was 87.5% and 87.5%. DLX was also more active than comparators against PSA, with DLX 68.7%S, while LEV was 43.3%S and CIP was 50.7%S.

Conclusion

DLX had good activity against recent CF isolates from US hospitals, and had the highest percent susceptibility of the quinolones tested against MSSA and PSA. These in vitro data suggest that DLX could be a useful therapy when coverage of both MSSA and PSA is needed.

Disclosures

Dee Shortridge, PhD, AbbVie: Grant/Research Support|JMI Laboratory: Employee|Melinta: Grant/Research Support|Menarini: Grant/Research Support|Shionogi: Grant/Research Support Jennifer M. Streit, BS, MT(ASCP), Cidara: Grant/Research Support|GSK: Grant/Research Support|Melinta: Grant/Research Support|Shionogi: Grant/Research Support Michael D. Huband, BS, AbbVie: Grant/Research Support|Melinta: Grant/Research Support Mariana Castanheira, PhD, AbbVie: Grant/Research Support|Cidara: Grant/Research Support|GSK: Grant/Research Support|Melinta: Grant/Research Support|Pfizer: Grant/Research Support|Shionogi: Grant/Research Support.

642. In Vitro Activity of Cefiderocol and Comparator Agents Against Molecularly Characterized Enterobacterales Clinical Isolates Causing Infection in United States Hospitals (2020-2021)

Background

Cefiderocol (CFDC) is a siderophore cephalosporin that hijacks the Gram-negative bacteria iron transport system to facilitate cell entry and reach its target. CFDC remains stable to hydrolysis in the presence of serine β-lactamases (ESBLs, KPC, and OXA-type carbapenemases) and metallo-β-lactamases (MBL). CFDC and comparator activities were analyzed against Enterobacterales (ENT), including molecularly characterized isolates, as part of the SENTRY Antimicrobial Surveillance Program in the USA.

Methods

8,328 ENT were collected from 32 sites in 2020-2021. Susceptibility testing was performed by broth microdilution. CFDC testing used iron-depleted media. CLSI breakpoints were used. E. coli, K. pneumoniae, and P. mirabilis with ceftriaxone, ceftazidime, or aztreonam MIC ≥2 μg/mL, and any ENT displaying MIC ≥2 μg/mL for imipenem (excluded for P. mirabilis, P. penneri, and indole-positive Proteeae) or meropenem (MER), were subjected to genome sequencing and screening of β-lactamase genes.

Results

In general, CFDC (≥ 99.9% susceptible [S]), imipenem-relebactam (IMR; 99.4-100%S), meropenem-vaborbactam (MEV; 100%S), and ceftazidime-avibactam (CZA; 100%S) were active against carbapenem-susceptible ENT that carried ESBL and/or AmpC genes (Table). CFDC (MIC50/90, 0.5/4 μg/mL; 98.4%S) and CZA (MIC50/90, 1/8 μg/mL; 91.2%S) were the most active agents against carbapenem-nonS isolates, whereas IMR (MIC50/90, 0.25/4 μg/mL; 81.6%S) and MEV (MIC50/90, 0.12/8 μg/mL; 86.4%S) had suboptimal activity. CFDC (MIC50/90, 0.5/2 μg/mL), IMR (MIC50/90, 0.12/0.5 μg/mL), MEV (MIC50/90, 0.03/0.5 μg/mL), and CZA (MIC50/90, 1/2 μg/mL) were active (100%S) against the KPC subset. CFDC (MIC, 0.5-4 μg/mL; 100%S) was also active against ENT carrying MBL genes, whereas CFDC (MIC, 0.5-2 μg/mL; 100%S) and CZA (1-4 μg/mL; 100%S) were active against isolates carrying blaOXA-48-like.

Conclusion

CFDC activity was consistent, regardless of phenotypes or genotypes, including against isolates carrying carbapenemase genes other than blaKPC, where approved β-lactam/β-lactamase inhibitor combinations showed limited activity. These data reinforce CFDC as an important option for the treatment of infections caused by ENT and resistant subsets.

Disclosures

Rodrigo E. Mendes, PhD, AbbVie: Grant/Research Support|Cidara: Grant/Research Support|GSK: Grant/Research Support|Melinta: Grant/Research Support|Nabriva Therapeutics: Grant/Research Support|Office for Assistant Secretary of Defense for Health Affairs: Grant/Research Support|Pfizer: Grant/Research Support|Shionogi: Grant/Research Support|Spero Therapeutics: Grant/Research Support John H. Kimbrough, PhD, AbbVie: Grant/Research Support|GSK: Grant/Research Support Valerie Kantro, BA, AbbVie: Grant/Research Support|GSK: Grant/Research Support|Melinta: Grant/Research Support|Shionogi: Grant/Research Support Dee Shortridge, PhD, AbbVie: Grant/Research Support|JMI Laboratory: Employee|Melinta: Grant/Research Support|Menarini: Grant/Research Support|Shionogi: Grant/Research Support Helio S. Sader, MD, PhD, AbbVie: Grant/Research Support|Cidara: Grant/Research Support|Melinta: Grant/Research Support|Nabriva Therapeutics: Grant/Research Support|Pfizer: Grant/Research Support Jennifer M. Streit, BS, MT(ASCP), Cidara: Grant/Research Support|GSK: Grant/Research Support|Melinta: Grant/Research Support|Shionogi: Grant/Research Support Mariana Castanheira, PhD, AbbVie: Grant/Research Support|Cidara: Grant/Research Support|GSK: Grant/Research Support|Melinta: Grant/Research Support|Pfizer: Grant/Research Support|Shionogi: Grant/Research Support.

2044. In Vitro Activity of Omadacycline Against 14,000 Bacterial Isolates from the United States by Infection Type (2020-2021)

Background

Omadacycline (OMC) is a novel tetracycline class (aminomethylcycline) antibacterial FDA approved for treatment of acute bacterial skin and skin structure infection (ABSSSI) and community-acquired bacterial pneumonia (CABP) caused by indicated organisms. OMC is active against bacterial isolates expressing resistance to tetracycline, penicillin, fluoroquinolones, macrolides, and vancomycin. This study has been funded in whole or in part by Federal funds from the U.S. Department of Health and Human Services, Biomedical Advanced Research and Development Authority (BARDA) within the Office of the Assistant Secretary for Preparedness and Response, under Contract No. 75A50120C00001.

Methods

14,000 bacterial clinical isolates were collected from 31 medical centers in the USA (2020-2021) in the SENTRY Surveillance Program. Isolates were collected from the following infection types: bloodstream (24.1%), pneumonia in hospitalized patients (22.6%), skin and skin structure (SSSI; 22.4%), urinary tract (15.9%), intraabdominal (5.5%), community acquired respiratory tract (8.3%) and other (1.2%). Identifications were confirmed by MALDI-TOF. Susceptibility testing of OMC and comparators was conducted according to CLSI M07 (2018) and M100 (2022) guidelines. OMC MIC results were interpreted using FDA breakpoints (BPs).

Results

OMC demonstrated potent in vitro activity against S. aureus (MIC90, 0.12 mg/L; 99.0% susceptible [S]) from SSSI, including 98.0% of MRSA (Table). From RTI, 99.6% of MSSA were S. 97.6% of S. lugdunensis and 95.5% of S. anginosus group isolates from SSSI were susceptible to OMC. All S. pyogenes and E. faecalis (including vancomycin-resistant [R]) isolates from SSSI were S to OMC. 99.8% of S. pneumoniae isolates from RTI were S to OMC, as were 100% of penicillin-R and tetracycline-R strains. H. influenzae susceptibility to OMC was 99.8%. Susceptibility of E. cloacae and K. pneumoniae isolates from all infection types to OMC was 88.9% and 90.4%, respectively.

Conclusion

OMC demonstrated potent in vitro activity against staphylococci, streptococci, E. faecalis, H. influenzae, E. cloacae, and K. pneumoniae isolates, including drug-resistant strains, regardless of infection type.

Disclosures

Michael D. Huband, BS, AbbVie: Grant/Research Support|Melinta: Grant/Research Support Jennifer M. Streit, BS, MT(ASCP), Cidara: Grant/Research Support|GSK: Grant/Research Support|Melinta: Grant/Research Support|Shionogi: Grant/Research Support Helio S. Sader, MD, PhD, AbbVie: Grant/Research Support|Cidara: Grant/Research Support|Melinta: Grant/Research Support|Nabriva Therapeutics: Grant/Research Support|Pfizer: Grant/Research Support Mariana Castanheira, PhD, AbbVie: Grant/Research Support|Cidara: Grant/Research Support|GSK: Grant/Research Support|Melinta: Grant/Research Support|Pfizer: Grant/Research Support|Shionogi: Grant/Research Support.

1675. Activity of Gepotidacin Against Escherichia coli Isolates from Community-acquired Urinary Tract Infections Collected Between 2019-2021 in the United States

Background

Gepotidacin is a novel, bactericidal, first-in-class triazaacenaphthylene antibiotic that inhibits bacterial DNA replication by a distinct mechanism of action that confers activity against most strains of target pathogens, such as Escherichia coli, Staphylococcus saprophyticus, and Neisseria gonorrhoeae, including those resistant to current antibiotics. This study reports on the in vitro activity of gepotidacin and other oral antibiotics tested against E. coli clinical isolates collected from patients with UTIs for a gepotidacin UTI global surveillance study as part of the SENTRY Antimicrobial Surveillance Program.

Methods

A total of 1,978 E. coli isolates were collected between 2019-2021 from 47 medical centers within the US. All isolates were cultured from urine specimens collected from patients seen in emergency and outpatient medical services representative of community-acquired infections. Bacterial identifications were confirmed by MALDI-TOF. Isolates were tested for susceptibility by CLSI methods at a central laboratory (JMI Laboratories). MIC results for oral antibiotics licensed for the treatment of uUTI, multidrug-resistant (MDR), and extended-spectrum β-lactamase (ESBL) subsets were interpreted per CLSI criteria.

Results

Gepotidacin (MIC50/90, 2/4 mg/L) displayed good activity against 1,978 E. coli isolates, with 98.3% of all observed gepotidacin MICs ≤4 mg/L (Table). Susceptibility (S) rates for other oral agents tested against these isolates were: amoxicillin-clavulanate (83.7%S), ampicillin (50.9%S), ciprofloxacin (79.1%S), fosfomycin (99.7%S), mecillinam (94.2%S), nitrofurantoin (98.2%S), and trimethoprim-sulfamethoxazole (71.3%S). When tested against the drug-resistant subsets, gepotidacin maintained similar MIC50/90 values (1-2/4 mg/L). Gepotidacin was also active against ESBL and MDR E. coli isolates, inhibiting 94.7% and 95.9%, respectively, at gepotidacin concentrations ≤ 4 mg/L.

Conclusion

Gepotidacin demonstrated potent in vitro activity against contemporary community-acquired E. coli urine isolates. This activity was maintained among isolates demonstrating resistance to other oral standard of care antibiotics including ESBL, FQ-R, and MDR E. coli.

Disclosures

SJ Ryan Arends, PhD, AbbVie: Grant/Research Support|GSK: Grant/Research Support|Nabriva Therapeutics: Grant/Research Support|Shionogi: Grant/Research Support Nicole E. Scangarella-Oman, MS, GlaxoSmithKline plc.: Employee and shareholder Lindsey Tholen, BS (ASCP), GSK: Board Member|GSK: work for hire|Shionogi: Grant/Research Support Jennifer M. Streit, BS, MT(ASCP), Cidara: Grant/Research Support|GSK: Grant/Research Support|Melinta: Grant/Research Support|Shionogi: Grant/Research Support Rodrigo E. Mendes, PhD, AbbVie: Grant/Research Support|Cidara: Grant/Research Support|GSK: Grant/Research Support|Melinta: Grant/Research Support|Nabriva Therapeutics: Grant/Research Support|Office for Assistant Secretary of Defense for Health Affairs: Grant/Research Support|Pfizer: Grant/Research Support|Shionogi: Grant/Research Support|Spero Therapeutics: Grant/Research Support.

1734. Susceptibility of Cefiderocol between US Census Regions against Gram-Negative Organisms collected from the SENTRY Surveillance Program: 2020-2021

Background

Cefiderocol (CFDC) is a siderophore-conjugated cephalosporin with broad activity against Gram-negative (GN) bacteria, including multidrug-resistant organisms. GN bacteria such as Enterobacterales (ENT), Pseudomonas aeruginosa (PsA), Acinetobacter baumannii complex (ABC), and Stenotrophomonas maltophilia (StM) can be challenging to treat and are often carbapenem-resistant (CR). Regional susceptibility of CFDC and comparators were investigated against US GN isolates collected in 2020-2021 as part of the SENTRY Antimicrobial Surveillance Program.

Methods

GN pathogens were consecutively collected from 32 US hospitals between 2020 to 2021. Susceptibility testing was performed using the broth microdilution method. CFDC was tested in iron-depleted cation-adjusted Mueller-Hinton broth. FDA or CLSI breakpoints were used where available. Other agents tested included the beta-lactam/beta-lactamase inhibitor (BL/BLI) combinations ceftazidime-avibactam, ceftolozane-tazobactam, imipenem-relebactam, meropenem-vaborbactam, piperacillin-tazobactam, and ampicillin-sulbactam. CR-PsA, or CRAB was defined as meropenem resistant while CRE was defined as imipenem or meropenem resistant by CLSI breakpoints.

Results

A total of 8328 ENT, 2241 PsA, 586 ABC, and 404 StM were collected. For ENT and PsA, CFDC susceptibility between the 9 US Census regions remained above 98% susceptible by CLSI or FDA breakpoints in all regions (Table 1). Amongst the BL/BLI combinations, the majority had >90% susceptibility across regions except for piperacillin-tazobactam with 79.7% for ENT and 65.9% for PsA in the MidAtlantic by FDA breakpoints. For ABC and StM, CFDC susceptibility was > 88% across all regions. For CR pathogens, 96 CRE, 327 CR-PsA, and 199 CRAB were collected. CFDC had >87.5% susceptibility in all regions for CRE and CR-PSA. For CRAB, 4 regions were > 87.5% by FDA breakpoints and the lowest was 63.6% in 11 isolates in the Mountain region (Table 2). For CRAB, every BL/BLI had susceptibility ≤27.3% in every region. Ampicillin-sulbactam had 27.3% susceptibility in the Mountain region. Table 1

Susceptibility of Cefiderocol against Enterobacterales, Pseudomonas aeruginosa, Acinetobacter baumannii complex and Stenotrophomonas maltiphilia isolates in the cefiderocol program collected from medical centers in the USA Table 2:

Susceptibility of cefiderocol against CRE, CR Pseudomonas aeruginosa, and CR Acinetobacter baumannii complex isolates in the cefiderocol program collected from medical centers in the USA

Conclusion

US GN isolates, including CR pathogens, had high susceptibilities to CFDC across the US census regions. CFDC remains an important treatment option for GN infections in all US census regions.

Disclosures

Frank H. Kung, PhD, Shionogi Inc: Employee Sean Nguyen, n/a, Shionogi: Employee Christine M. Slover, PharmD, Shionogi: Employee Dee Shortridge, PhD, AbbVie: Grant/Research Support|JMI Laboratory: Employee|Melinta: Grant/Research Support|Menarini: Grant/Research Support|Shionogi: Grant/Research Support Jennifer M. Streit, BS, MT(ASCP), Cidara: Grant/Research Support|GSK: Grant/Research Support|Melinta: Grant/Research Support|Shionogi: Grant/Research Support Roger Echols, MD, Shionogi: Advisor/Consultant Roger Echols, MD, Shionogi: Advisor/Consultant Roger Echols, MD, Shionogi: Advisor/Consultant Miki Takemura, n/a, Shionogi: Employee Yoshinori Yamano, PhD, Shionogi: Employee.

645. Trends in the Susceptibility of US Acinetobacter baumannii-calcoaceticus Species Complex and Stenotrophomonas maltophilia Isolates to Minocycline, 2014-2021

Background

Acinetobacter baumannii-calcoaceticus species complex (ACB) and Stenotrophomonas maltophilia (SM) are opportunistic, non-fermentative organisms that can cause serious hospital-acquired infections in immunocompromised patients. These pathogens are inherently resistant to several common drug classes and often acquire other resistance mechanisms, making them difficult to treat. In this study, we analyzed the susceptibility of contemporary ACB and SM isolates to minocycline (MIN), levofloxacin (LEV), meropenem (MER) for ACB, and trimethoprim-sulfamethoxazole (T/S) for SM. Isolates were collected as a part of the SENTRY Antimicrobial Surveillance Program from 2014-2021.

Susceptibilities of SM and ACB to MIN and comparators, 2014-2021

Methods

Isolates were collected from hospitalized patients in 35 US medical centers. Hospitals submitted 1 isolate per patient per infection episode that met local criteria for being the likely causative pathogen. Identification was performed by the submitting laboratory and confirmed by JMI Laboratories with matrix-assisted laser desorption ionization-time of flight mass spectrometry or other standard methods as required. Isolates were tested for susceptibility (S) to MIN and comparators using the CLSI broth microdilution method. All infection types were included in the analysis. CLSI (2022) breakpoints were applied.

Results

A total of 1,029 ACB and 1,520 SM were tested. Pneumonia in hospitalized patients was the most common infection from which ACB (57.0%) and SM (73.9%) were isolated. The %S of the agents tested against the organisms in this study are shown in the table. MIN had the highest %S for ACB (86.2%S) and SM (99.5%S). The %S of ACB and SM to all 3 agents varied over the period studied. MIN %S to ACB decreased in 2020 (80.6%) but rebounded in 2021 (86.2%). LEV and MER showed an overall trend of increasing S for ACB, with slightly lower %S in 2020-2021. SM had stable %S to MIN and T/S ( &gt;98.3% and &gt;93.7%, respectively). LEV varied from 84.3%S (2015) to 69.2%S (2018).

Conclusion

%S to MIN remained stable and higher than other agents tested for both ACB and SM, pathogens which have limited therapeutic alternatives. ACB showed &lt; 6% decrease in %S to all 3 agents in 2020-2021. These in vitro data suggest that MIN is a useful treatment option for infections caused by ACB or SM.

Disclosures

Dee Shortridge, PhD, AbbVie: Grant/Research Support|JMI Laboratory: Employee|Melinta: Grant/Research Support|Menarini: Grant/Research Support|Shionogi: Grant/Research Support Cecilia G. Carvalhaes, MD, PhD, AbbVie: Grant/Research Support|Cidara: Grant/Research Support|Melinta: Grant/Research Support|Pfizer: Grant/Research Support Jennifer M. Streit, BS, MT(ASCP), Cidara: Grant/Research Support|GSK: Grant/Research Support|Melinta: Grant/Research Support|Shionogi: Grant/Research Support Mariana Castanheira, PhD, AbbVie: Grant/Research Support|Cidara: Grant/Research Support|GSK: Grant/Research Support|Melinta: Grant/Research Support|Pfizer: Grant/Research Support|Shionogi: Grant/Research Support.

646. Activity of Oritavancin and Comparator Agents Against Coagulase-negative Staphylococci Causing Bloodstream Infections in US Medical Centers (2017-2019)

Background

Coagulase-negative staphylococci (CoNS) is a common organism group implicated in catheter-related bloodstream infection (BSI) and infective endocarditis. Prompt appropriate antimicrobial therapy is crucial for suspected or confirmed invasive infections. The in vitro activity of oritavancin (ORI) and comparators was evaluated against CoNS causing BSI in US medical centers.

Methods

587 CoNS isolates (1/patient) were consecutively collected in 30 US centers in 2017-2019. Bacterial identification was performed by MALDI-TOF, and susceptibility testing using CLSI broth microdilution methodology in a central laboratory. CLSI breakpoints were applied for comparators and the ORI susceptible (S) breakpoint for S. aureus (≤0.12 mg/L) was used for in vitro comparison only.

Results

The most common species were S. epidermidis (Sepi; 62.4%; 366), followed by S. hominis (Shom; 13.1%; 77), S. capitis (Scap; 7.3%; 43), S. lugdunensis (Slug; 5.1%; 30), and S. haemolyticus (Shae; 4.3%; 25). 12 other species represented < 10 (1.5%) isolates each. Overall, 59.1% of isolates were methicillin-resistant (MR), with the highest rate in Sepi (73.2%), followed by Shae (68.0%), Shom (46.8%), and Scap (30.2%). No MR isolates were detected in Slug. ORI (MIC_50/90, 0.06/0.12 mg/L) inhibited 96.1% of CoNS at ≤0.12 mg/L. Linezolid (LZD; MIC_50/90, 1/1 mg/L; 96.4%S), daptomycin (DAP; MIC_50/90, 0.25/0.5 mg/L; 100%S), and vancomycin (VAN; MIC_50/90, 1/2 mg/L; 100%S) were also active against CoNS. ORI displayed similar MIC₅₀ (0.03-0.06 mg/L) and MIC₉₀ (0.12-0.25 mg/L) values against Sepi, Shom, Scap, and Shae, and inhibited 96.0%, 96.1%, 97.7%, and 84.0% of these isolates at ≤0.12 mg/L, respectively. All Slug isolates were inhibited by ORI at ≤0.015 mg/L. ORI inhibited 94.8% of all MRCoNS at ≤0.12 mg/L, and 95.5%, 94.4%, 92.3%, and 82.4% of MR Sepi, Shom, Scap, and Shae species, respectively. VAN, DAP, and LZD inhibited 100.0%, 100.0%, and 93.9% of MRCoNS isolates at their susceptible breakpoints, respectively.

Conclusion

ORI was highly active and inhibited ≥96% of all CoNS and individual species ( >10 isolates) at ≤0.12 mg/L, regardless of methicillin profile, except for Shae. VAN, DAP, and LZD were also active against CoNS causing BSI in US medical centres.

Disclosures

Cecilia G. Carvalhaes, MD, PhD, AbbVie: Grant/Research Support|Cidara: Grant/Research Support|Melinta: Grant/Research Support|Pfizer: Grant/Research Support Helio S. Sader, MD, PhD, AbbVie: Grant/Research Support|Cidara: Grant/Research Support|Melinta: Grant/Research Support|Nabriva Therapeutics: Grant/Research Support|Pfizer: Grant/Research Support Jennifer M. Streit, BS, MT(ASCP), Cidara: Grant/Research Support|GSK: Grant/Research Support|Melinta: Grant/Research Support|Shionogi: Grant/Research Support Rodrigo E. Mendes, PhD, AbbVie: Grant/Research Support|Cidara: Grant/Research Support|GSK: Grant/Research Support|Melinta: Grant/Research Support|Nabriva Therapeutics: Grant/Research Support|Office for Assistant Secretary of Defense for Health Affairs: Grant/Research Support|Pfizer: Grant/Research Support|Shionogi: Grant/Research Support|Spero Therapeutics: Grant/Research Support.

660. In vitro activity of cefiderocol against difficult-to-treat resistance European Gram-negative bacterial pathogens from the multi-national sentinel surveillance study, SENTRY in 2020 and 2021

Background

Difficult-to-treat resistance (DTR) organisms are defined as non-susceptible to all first-line high-efficacy, low-toxicity antibiotics (penicillins, cephalosporins, carbapenems and fluoroquinolones), leaving physicians with limited treatment options. Cefiderocol is a parenteral siderophore cephalosporin with potent activity against aerobic Gram-negative pathogens, including carbapenem-resistant strains. We evaluated the in vitro activity of cefiderocol and comparators against DTR pathogens collected in Europe by the SENTRY surveillance study in 2020 and 2021.

Methods

A total of 11434 clinical isolates of Gram-negative bacilli were systematically collected from 16 EU countries, Israel and Turkey in 2020 and 2021. Minimum inhibitory concentrations (MICs) were determined by broth microdilution for a panel of twenty-two antibiotics according to CLSI guidelines. All antibiotics were tested in cation-adjusted Mueller-Hinton broth (CAMHB) except for cefiderocol, for which iron-depleted CAMHB was used. Susceptibility was determined according to CLSI breakpoints, and DTR pathogens were defined as being resistant to cefepime, ceftazidime ceftriaxone, imipenem, meropenem, ciprofloxacin and levofloxacin according to CLSI breakpoints.

Results

Among 11434 Gram-negative isolates collected in 2020 and 2021, 792 (7.0%) were resistant to all 1^st line therapy including cephalosporins, carbapenems and fluoroquinolone and could be defined as DTR. DTR was most frequently observed in Acinetobacter spp. (530/931, 56.9%), Enterobacterales (201/7739, 2.6%) and Pseudomonas aeruginosa (61/2440, 2.5. Based on CLSI breakpoints, cefiderocol was the most active antibiotic tested against DTR-Acinetobacter spp. (MIC₉₀= 2mg/L, 97.4% susceptibility). Ampicillin/sulbactam was active in less than 1% of the DTR-Acinetobacter spp isolates. None of the drugs recommended by the IDSA for the treatment of resistant Gram-negative infections were as potent as cefiderocol (Table 1).

Conclusion

Cefiderocol was the only treatment option with demonstrated in vitro activity against more than 95% of all the tested DTR Gram-negative pathogens with limited treatment options.

Disclosures

Anne Laurence Santerre Henriksen, PhD, Shionogi: Contractor|UTILITY therapeutics Ltd: Advisor/Consultant Christopher M. Longshaw, PhD, Shionogi: Employee Dee Shortridge, PhD, AbbVie: Grant/Research Support|JMI Laboratory: Employee|Melinta: Grant/Research Support|Menarini: Grant/Research Support|Shionogi: Grant/Research Support Jennifer M. Streit, BS, MT(ASCP), Cidara: Grant/Research Support|GSK: Grant/Research Support|Melinta: Grant/Research Support|Shionogi: Grant/Research Support Miki Takemura, n/a, Shionogi: Employee Yoshinori Yamano, PhD, Shionogi: Employee.

Activity of meropenem/vaborbactam and comparators against non-carbapenemase-producing carbapenem-resistant Enterobacterales isolates from Europe

Background

Carbapenem-resistant Enterobacterales (CRE) isolates have disseminated worldwide. CREs usually produce a carbapenemase; however, some isolates are negative for known carbapenemases. In this study, we evaluated the activity of meropenem/vaborbactam and comparators against CREs without a carbapenemase (nonCP CREs) collected from European hospitals from 2016 to 2019.

Materials and methods

23 043 Enterobacterales clinical isolates were collected in 41 hospitals located in 20 countries. Susceptibility (S) testing was performed using the broth microdilution method. CLSI/EUCAST (2021) interpretive criteria were used. 978 CREs were identified with MICs &gt;2 mg/L to meropenem or imipenem. Whole-genome sequencing was performed on each CRE isolate. 125 isolates were negative for carbapenemase genes, including blaKPC, blaNDM, blaIMP, blaVIM and blaOXA-48-like. NonCP CRE isolates were analysed for the presence of other β-lactamases, multilocus sequence types (ST) and mutations in outer membrane protein (OMP) sequences.

Results

Most nonCP CRE were Klebsiella pneumoniae (KPN; n = 97/125). 84.0% of nonCP CRE (n = 105) were from Poland, including 88 KPN. The most common β-lactamase was blaCTX-M-15 in 92/125 isolates. OMP disruptions or alterations were noted among 76 KPN. Among KPN isolates that had MLST typing, 30 belonged to ST11, 18 to ST152 and 17 to ST147, while 13 other STs were observed. Susceptibility to meropenem/vaborbactam was 96.0/97.6% (CLSI/EUCAST) while meropenem was 2.4/8.0%S.

Conclusions

Meropenem/vaborbactam had potent in vitro activity against CRE isolates that lacked known carbapenemases. Resistance mechanisms observed among nonCP CREs included acquired β-lactamases and OMP alterations. These results indicate that meropenem/vaborbactam may be a useful treatment for infections caused by nonCP CREs.

Five-year analysis of the in vitro activity of tedizolid against a worldwide collection of indicated species causing clinical infections: results from the Surveillance of Tedizolid Activity and Resistance (STAR) programme

Objectives

The Surveillance of Tedizolid Activity and Resistance (STAR) programme monitored the tedizolid activity against Staphylococcus aureus, Enterococcus faecalis, Streptococcus pyogenes, Streptococcus agalactiae and Streptococcus anginosus group. We evaluated the antimicrobial susceptibility of 47 400 unique Gram-positive clinical isolates from the STAR programme collected from USA (21 243), Europe (17 674), Asia-Pacific (4954) and Latin America (3529) medical centres (2015–19).

Methods

All isolates were tested for susceptibility by reference broth microdilution method. WGS and in silico analysis were performed on linezolid-non-susceptible (NS) isolates.

Results

Tedizolid was active against ≥99.9% of S. aureus (100.0% of MSSA and >99.9% of MRSA), E. faecalis, S. pyogenes, S. agalactiae and S. anginosus group isolates, with MIC₅₀ values ranging from 0.12 to 0.25 mg/L and MIC₉₀ values of 0.25 mg/L. Linezolid, vancomycin and daptomycin were also active agents against these organisms. Tedizolid inhibited all VRE and 73.1% of linezolid-NS E. faecalis isolates. Ampicillin and daptomycin retained 100.0% activity against VRE and linezolid-NS E. faecalis isolates. Linezolid-NS E. faecalis isolates carried mostly the optrA gene. G2576T alterations in the 23S rRNA were observed in one linezolid-NS S. aureus isolate and one linezolid-NS E. faecalis isolate.

Conclusions

No resistance trends were observed for tedizolid during the study period.

In Vitro Activity of Cefiderocol against U.S. and European Gram-Negative Clinical Isolates Collected in 2020 as Part of the SENTRY Antimicrobial Surveillance Program

Cefiderocol is a siderophore-conjugated cephalosporin with broad activity against Gram-negative (GN) bacteria, including carbapenem-resistant Enterobacterales (CRE), Pseudomonas aeruginosa, Acinetobacter spp., and Stenotrophomonas maltophilia. Cefiderocol was approved by the FDA for treatment of complicated urinary tract infection, hospital-acquired bacterial pneumonia, and ventilator-associated bacterial pneumonia and by the European Medicines Agency (EMA) for aerobic GN infections in adults with few treatment options. In this study, we analyzed the susceptibility of cefiderocol against GN clinical isolates that were collected from hospitalized patients in the United States and Europe in 2020 as part of the SENTRY Antimicrobial Surveillance Program. GN isolates, including 8,047 Enterobacterales, 2,282 P. aeruginosa, 650 Acinetobacter species, and 338 S. maltophilia isolates, were consecutively collected from patients in 66 hospitals in 19 countries. Susceptibility testing was performed using the CLSI broth microdilution method, and cefiderocol was tested in iron-depleted cation-adjusted Mueller-Hinton broth. Cefiderocol activity against resistant isolates, including CRE and extensively drug-resistant (XDR) isolates, was determined. Enterobacterales susceptibility to cefiderocol was 99.8% (CLSI), and CRE susceptibility was 98.2%. Cefiderocol was the most active antimicrobial against all P. aeruginosa isolates with MIC50/90 values of 0.12/0.5 mg/L, respectively (99.6% susceptible). A total of 256 P. aeruginosa isolates were XDR, 97.3% were susceptible to cefiderocol, and 7.4% were susceptible to meropenem. Acinetobacter susceptibility to cefiderocol was 97.7%. S. maltophilia susceptibility to cefiderocol was 100.0% (CLSI, 2021) and 97.9% (CLSI, 2022). These in vitro data suggest that cefiderocol is an important therapeutic option for the treatment of infections caused by Gram-negative pathogens, including isolates resistant to carbapenems with few therapeutic options. IMPORTANCE Cefiderocol is the first siderophore-conjugated cephalosporin approved for use in the treatment of human bacterial infections. Cefiderocol has broad-spectrum Gram-negative activity against difficult-to-treat bacterial pathogens that can cause serious infections. Our study examines the activity of cefiderocol against a large global collection of Gram-negative clinical isolates collected from hospitalized patients in 2020. In addition, we compare the activities of cefiderocol and recently approved β-lactam-β-lactamase inhibitor combinations against various antimicrobial-resistant pathogen groups including carbapenem-resistant Enterobacterales, meropenem-resistant Pseudomonas aeruginosa, and meropenem-resistant Acinetobacter spp. as well as isolates resistant to most classes of antimicrobial drugs. Cefiderocol was the most active antimicrobial tested against the isolates in this study. Our in vitro data suggest that cefiderocol may be useful for treatment of serious infections caused by drug-resistant Gram-negative organisms for patients with limited treatment options.

155. In Vitro Evaluation of Delafloxacin Activity Against Contemporary US Isolates from Community-Acquired Pneumonia and Community-Acquired Lower Respiratory Tract Infections: Results from the SENTRY Antimicrobial Surveillance Program (2014-2020)

Background

Delafloxacin (DLX) is a broad-spectrum fluoroquinolone antibacterial approved in the US for the treatment of community-acquired bacterial pneumonia (CABP). DLX is indicated to treat CABP caused by Streptococcus pneumoniae (SPN), Haemophilus influenzae (HI), Haemophilus parainfluenzae (HP), methicillin-susceptible Staphylococcus aureus (MSSA), Escherichia coli (EC), Klebsiella pneumoniae (KPN), Pseudomonas aeruginosa (PSA), Chlamydia pneumoniae, Mycoplasma pneumoniae and L. pneumophila. In this study, the in vitro susceptibilities of DLX and comparator quinolones were determined for clinical isolates from CAP and CA-lower respiratory tract infections (LRTIs).

Methods

CAP and CA-LRTI isolates were consecutively collected at 67 US medical centers participating in the SENTRY Surveillance Program during 2014-2020. Sites submitted 1 isolate per patient per infection episode. Isolate identification was determined at each site and confirmed using standard biochemical or molecular methods at JMI Laboratories. Susceptibility testing was performed according to CLSI broth microdilution methodology. CLSI (2021) interpretive criteria were applied, FDA criteria were used for DLX.

Results

The susceptibility results for DLX, levofloxacin (LEV), moxifloxacin (MOX), and ciprofloxacin (CIP) for the indicated species are shown in the table. As MOX does not have CLSI breakpoints for EC, KPN, or PSA, CIP was tested for those species instead. DLX had the highest percent susceptibility against MSSA (91.8%). SPN and HI were >97% susceptible, and HP was >91% for all 3 drugs. KPN susceptibility ranged from 86.4% for LEV to 76.9% for DLX. Susceptibilities for EC and PSA were similar for the 3 drugs, EC varied from 59.8% for LEV to 57.0% for DLX, and PSA varied from 71.6% for CIP to 64.0% to LEV.

Conclusion

DLX had good activity against recent CAP and CA-LRTI isolates from US hospitals. DLX had the highest susceptibility of the quinolones tested against MSSA. Quinolone-resistant SPN and HI were uncommon. These in vitro results suggest that DLX may be a useful therapeutic option for CABP caused by Gram-positive, Gram-negative and fastidious pathogens.

Disclosures

Dee Shortridge, PhD, AbbVie (formerly Allergan) (Research Grant or Support)Melinta Therapeutics, Inc. (Research Grant or Support)Melinta Therapeutics, LLC (Research Grant or Support)Shionogi (Research Grant or Support) Jennifer M. Streit, BS, GlaxoSmithKline, LLC (Research Grant or Support)Melinta Therapeutics, LLC (Research Grant or Support)Shionogi (Research Grant or Support)Spero Therapeutics (Research Grant or Support) Michael D. Huband, BS, AbbVie (formerly Allergan) (Research Grant or Support)Melinta Therapeutics, LLC (Research Grant or Support) Mariana Castanheira, PhD, AbbVie (formerly Allergan) (Research Grant or Support)Bravos Biosciences (Research Grant or Support)Cidara Therapeutics, Inc. (Research Grant or Support)Cipla Therapeutics (Research Grant or Support)Cipla USA Inc. (Research Grant or Support)GlaxoSmithKline (Research Grant or Support)Melinta Therapeutics, Inc. (Research Grant or Support)Melinta Therapeutics, LLC (Research Grant or Support)Pfizer, Inc. (Research Grant or Support)Qpex Biopharma (Research Grant or Support)Shionogi (Research Grant or Support)Spero Therapeutics (Research Grant or Support) Mariana Castanheira, PhD, Affinity Biosensors (Individual(s) Involved: Self): Research Grant or Support; Allergan (Individual(s) Involved: Self): Research Grant or Support; Amicrobe, Inc (Individual(s) Involved: Self): Research Grant or Support; Amplyx Pharma (Individual(s) Involved: Self): Research Grant or Support; Artugen Therapeutics USA, Inc. (Individual(s) Involved: Self): Research Grant or Support; Astellas (Individual(s) Involved: Self): Research Grant or Support; Basilea (Individual(s) Involved: Self): Research Grant or Support; Beth Israel Deaconess Medical Center (Individual(s) Involved: Self): Research Grant or Support; BIDMC (Individual(s) Involved: Self): Research Grant or Support; bioMerieux Inc. (Individual(s) Involved: Self): Research Grant or Support; BioVersys Ag (Individual(s) Involved: Self): Research Grant or Support; Bugworks (Individual(s) Involved: Self): Research Grant or Support; Cidara (Individual(s) Involved: Self): Research Grant or Support; Cipla (Individual(s) Involved: Self): Research Grant or Support; Contrafect (Individual(s) Involved: Self): Research Grant or Support; Cormedix (Individual(s) Involved: Self): Research Grant or Support; Crestone, Inc. (Individual(s) Involved: Self): Research Grant or Support; Curza (Individual(s) Involved: Self): Research Grant or Support; CXC7 (Individual(s) Involved: Self): Research Grant or Support; Entasis (Individual(s) Involved: Self): Research Grant or Support; Fedora Pharmaceutical (Individual(s) Involved: Self): Research Grant or Support; Fimbrion Therapeutics (Individual(s) Involved: Self): Research Grant or Support; Fox Chase (Individual(s) Involved: Self): Research Grant or Support; GlaxoSmithKline (Individual(s) Involved: Self): Research Grant or Support; Guardian Therapeutics (Individual(s) Involved: Self): Research Grant or Support; Hardy Diagnostics (Individual(s) Involved: Self): Research Grant or Support; IHMA (Individual(s) Involved: Self): Research Grant or Support; Janssen Research & Development (Individual(s) Involved: Self): Research Grant or Support; Johnson & Johnson (Individual(s) Involved: Self): Research Grant or Support; Kaleido Biosceinces (Individual(s) Involved: Self): Research Grant or Support; KBP Biosciences (Individual(s) Involved: Self): Research Grant or Support; Luminex (Individual(s) Involved: Self): Research Grant or Support; Matrivax (Individual(s) Involved: Self): Research Grant or Support; Mayo Clinic (Individual(s) Involved: Self): Research Grant or Support; Medpace (Individual(s) Involved: Self): Research Grant or Support; Meiji Seika Pharma Co., Ltd. (Individual(s) Involved: Self): Research Grant or Support; Melinta (Individual(s) Involved: Self): Research Grant or Support; Menarini (Individual(s) Involved: Self): Research Grant or Support; Merck (Individual(s) Involved: Self): Research Grant or Support; Meridian Bioscience Inc. (Individual(s) Involved: Self): Research Grant or Support; Micromyx (Individual(s) Involved: Self): Research Grant or Support; MicuRx (Individual(s) Involved: Self): Research Grant or Support; N8 Medical (Individual(s) Involved: Self): Research Grant or Support; Nabriva (Individual(s) Involved: Self): Research Grant or Support; National Institutes of Health (Individual(s) Involved: Self): Research Grant or Support; National University of Singapore (Individual(s) Involved: Self): Research Grant or Support; North Bristol NHS Trust (Individual(s) Involved: Self): Research Grant or Support; Novome Biotechnologies (Individual(s) Involved: Self): Research Grant or Support; Paratek (Individual(s) Involved: Self): Research Grant or Support; Pfizer (Individual(s) Involved: Self): Research Grant or Support; Prokaryotics Inc. (Individual(s) Involved: Self): Research Grant or Support; QPEX Biopharma (Individual(s) Involved: Self): Research Grant or Support; Rhode Island Hospital (Individual(s) Involved: Self): Research Grant or Support; RIHML (Individual(s) Involved: Self): Research Grant or Support; Roche (Individual(s) Involved: Self): Research Grant or Support; Roivant (Individual(s) Involved: Self): Research Grant or Support; Salvat (Individual(s) Involved: Self): Research Grant or Support; Scynexis (Individual(s) Involved: Self): Research Grant or Support; SeLux Diagnostics (Individual(s) Involved: Self): Research Grant or Support; Shionogi (Individual(s) Involved: Self): Research Grant or Support; Specific Diagnostics (Individual(s) Involved: Self): Research Grant or Support; Spero (Individual(s) Involved: Self): Research Grant or Support; SuperTrans Medical LT (Individual(s) Involved: Self): Research Grant or Support; T2 Biosystems (Individual(s) Involved: Self): Research Grant or Support; The University of Queensland (Individual(s) Involved: Self): Research Grant or Support; Thermo Fisher Scientific (Individual(s) Involved: Self): Research Grant or Support; Tufts Medical Center (Individual(s) Involved: Self): Research Grant or Support; Universite de Sherbrooke (Individual(s) Involved: Self): Research Grant or Support; University of Iowa (Individual(s) Involved: Self): Research Grant or Support; University of Iowa Hospitals and Clinics (Individual(s) Involved: Self): Research Grant or Support; University of Wisconsin (Individual(s) Involved: Self): Research Grant or Support; UNT System College of Pharmacy (Individual(s) Involved: Self): Research Grant or Support; URMC (Individual(s) Involved: Self): Research Grant or Support; UT Southwestern (Individual(s) Involved: Self): Research Grant or Support; VenatoRx (Individual(s) Involved: Self): Research Grant or Support; Viosera Therapeutics (Individual(s) Involved: Self): Research Grant or Support; Wayne State University (Individual(s) Involved: Self): Research Grant or Support

1254. Molecular Epidemiology of Escherichia coli Causing Urinary Tract Infections in United States and in vitro Activity of Tebipenem, Including Against Strain Lineage and Resistant subsets (2018-2020)

Background

Tebipenem (TBP) is an oral carbapenem in clinical development for treating complicated urinary tract infections (UTIs), including pyelonephritis. This study investigates the epidemiology of E. coli (EC) causing UTI in U.S. patients and the activity of TBP and comparators against various subsets.

Methods

A total of 2,395 EC recovered from urine samples during the 2018-2020 STEWARD Surveillance Program were included. Isolates were collected from medical centers in all 9 US Census Regions and centrally tested by reference broth microdilution method. MIC interpretation was based on CLSI criteria. Isolates that met MIC criteria were subjected to genome sequencing, followed by screening of extended-spectrum β-lactamase (ESBL) genes and epidemiology typing (MLST).

Results

A total of 16.1%, 15.4% and 14.6% of EC met the ESBL screening criteria in 2018, 2019 and 2020, respectively. 269/360 (74.7%) carried bla_CTX-M and 2/360 (0.6%) had bla_SHV-12. bla_CMY (33/360; 9.2%) was the most common cephalosporinase, followed by bla_DHA (7/360; 1.9%). A CRE phenotype was noted in 1 isolate from New York, which carried bla_KPC-2. Acquired genes were not detected in 56 strains. 50 ST types were noted in isolates that met the ESBL criteria screening, with the majority of isolates being ST131 (56.2%). 21 (6.7%) and 19 (6.0%) isolates belonged to ST38 and ST1193, respectively, followed by STs represented by 8 or less isolates. Among ST131, 56.5% carried bla_CTX-M from group 1 and 35.6% had genes associated with group 9. Overall, TBP showed consistent MIC₅₀ values throughout the subsets. ERT had activity (≥97.0% susceptible) against the various subsets; however, lower susceptibility rates (85.7-90.6%) were noted against isolates carrying plasmid AmpC. Other agents (ceftriaxone and cefazolin) had activity only against non-ESBL producers.

Conclusion

bla_CTX-M comprised the majority of acquired genes detected among ESBL strains, which belonged mostly to ST131, emphasizing the expansion of this clone. TBP showed consistent activity against all subsets, regardless of resistance genotype or lineage. These data support the clinical development of TBP as a convenient oral treatment option for UTI caused by EC.

Disclosures

Rodrigo E. Mendes, PhD, AbbVie (Research Grant or Support)AbbVie (formerly Allergan) (Research Grant or Support)Cipla Therapeutics (Research Grant or Support)Cipla USA Inc. (Research Grant or Support)ContraFect Corporation (Research Grant or Support)GlaxoSmithKline, LLC (Research Grant or Support)Melinta Therapeutics, Inc. (Research Grant or Support)Melinta Therapeutics, LLC (Research Grant or Support)Nabriva Therapeutics (Research Grant or Support)Pfizer, Inc. (Research Grant or Support)Shionogi (Research Grant or Support)Spero Therapeutics (Research Grant or Support) Timothy B. Doyle, AbbVie (formerly Allergan) (Research Grant or Support)Bravos Biosciences (Research Grant or Support)GlaxoSmithKline (Research Grant or Support)Melinta Therapeutics, Inc. (Research Grant or Support)Pfizer, Inc. (Research Grant or Support)Shionogi (Research Grant or Support)Spero Therapeutics (Research Grant or Support) Ian A. Critchley, Ph.D., Spero Therapeutics (Employee, Shareholder) Nicole Cotroneo, Spero Therapeutics (Employee, Shareholder) Jennifer M. Streit, BS, GlaxoSmithKline, LLC (Research Grant or Support)Melinta Therapeutics, LLC (Research Grant or Support)Shionogi (Research Grant or Support)Spero Therapeutics (Research Grant or Support) Mariana Castanheira, PhD, AbbVie (formerly Allergan) (Research Grant or Support)Bravos Biosciences (Research Grant or Support)Cidara Therapeutics, Inc. (Research Grant or Support)Cipla Therapeutics (Research Grant or Support)Cipla USA Inc. (Research Grant or Support)GlaxoSmithKline (Research Grant or Support)Melinta Therapeutics, Inc. (Research Grant or Support)Melinta Therapeutics, LLC (Research Grant or Support)Pfizer, Inc. (Research Grant or Support)Qpex Biopharma (Research Grant or Support)Shionogi (Research Grant or Support)Spero Therapeutics (Research Grant or Support) Mariana Castanheira, PhD, Affinity Biosensors (Individual(s) Involved: Self): Research Grant or Support; Allergan (Individual(s) Involved: Self): Research Grant or Support; Amicrobe, Inc (Individual(s) Involved: Self): Research Grant or Support; Amplyx Pharma (Individual(s) Involved: Self): Research Grant or Support; Artugen Therapeutics USA, Inc. (Individual(s) Involved: Self): Research Grant or Support; Astellas (Individual(s) Involved: Self): Research Grant or Support; Basilea (Individual(s) Involved: Self): Research Grant or Support; Beth Israel Deaconess Medical Center (Individual(s) Involved: Self): Research Grant or Support; BIDMC (Individual(s) Involved: Self): Research Grant or Support; bioMerieux Inc. (Individual(s) Involved: Self): Research Grant or Support; BioVersys Ag (Individual(s) Involved: Self): Research Grant or Support; Bugworks (Individual(s) Involved: Self): Research Grant or Support; Cidara (Individual(s) Involved: Self): Research Grant or Support; Cipla (Individual(s) Involved: Self): Research Grant or Support; Contrafect (Individual(s) Involved: Self): Research Grant or Support; Cormedix (Individual(s) Involved: Self): Research Grant or Support; Crestone, Inc. (Individual(s) Involved: Self): Research Grant or Support; Curza (Individual(s) Involved: Self): Research Grant or Support; CXC7 (Individual(s) Involved: Self): Research Grant or Support; Entasis (Individual(s) Involved: Self): Research Grant or Support; Fedora Pharmaceutical (Individual(s) Involved: Self): Research Grant or Support; Fimbrion Therapeutics (Individual(s) Involved: Self): Research Grant or Support; Fox Chase (Individual(s) Involved: Self): Research Grant or Support; GlaxoSmithKline (Individual(s) Involved: Self): Research Grant or Support; Guardian Therapeutics (Individual(s) Involved: Self): Research Grant or Support; Hardy Diagnostics (Individual(s) Involved: Self): Research Grant or Support; IHMA (Individual(s) Involved: Self): Research Grant or Support; Janssen Research & Development (Individual(s) Involved: Self): Research Grant or Support; Johnson & Johnson (Individual(s) Involved: Self): Research Grant or Support; Kaleido Biosceinces (Individual(s) Involved: Self): Research Grant or Support; KBP Biosciences (Individual(s) Involved: Self): Research Grant or Support; Luminex (Individual(s) Involved: Self): Research Grant or Support; Matrivax (Individual(s) Involved: Self): Research Grant or Support; Mayo Clinic (Individual(s) Involved: Self): Research Grant or Support; Medpace (Individual(s) Involved: Self): Research Grant or Support; Meiji Seika Pharma Co., Ltd. (Individual(s) Involved: Self): Research Grant or Support; Melinta (Individual(s) Involved: Self): Research Grant or Support; Menarini (Individual(s) Involved: Self): Research Grant or Support; Merck (Individual(s) Involved: Self): Research Grant or Support; Meridian Bioscience Inc. (Individual(s) Involved: Self): Research Grant or Support; Micromyx (Individual(s) Involved: Self): Research Grant or Support; MicuRx (Individual(s) Involved: Self): Research Grant or Support; N8 Medical (Individual(s) Involved: Self): Research Grant or Support; Nabriva (Individual(s) Involved: Self): Research Grant or Support; National Institutes of Health (Individual(s) Involved: Self): Research Grant or Support; National University of Singapore (Individual(s) Involved: Self): Research Grant or Support; North Bristol NHS Trust (Individual(s) Involved: Self): Research Grant or Support; Novome Biotechnologies (Individual(s) Involved: Self): Research Grant or Support; Paratek (Individual(s) Involved: Self): Research Grant or Support; Pfizer (Individual(s) Involved: Self): Research Grant or Support; Prokaryotics Inc. (Individual(s) Involved: Self): Research Grant or Support; QPEX Biopharma (Individual(s) Involved: Self): Research Grant or Support; Rhode Island Hospital (Individual(s) Involved: Self): Research Grant or Support; RIHML (Individual(s) Involved: Self): Research Grant or Support; Roche (Individual(s) Involved: Self): Research Grant or Support; Roivant (Individual(s) Involved: Self): Research Grant or Support; Salvat (Individual(s) Involved: Self): Research Grant or Support; Scynexis (Individual(s) Involved: Self): Research Grant or Support; SeLux Diagnostics (Individual(s) Involved: Self): Research Grant or Support; Shionogi (Individual(s) Involved: Self): Research Grant or Support; Specific Diagnostics (Individual(s) Involved: Self): Research Grant or Support; Spero (Individual(s) Involved: Self): Research Grant or Support; SuperTrans Medical LT (Individual(s) Involved: Self): Research Grant or Support; T2 Biosystems (Individual(s) Involved: Self): Research Grant or Support; The University of Queensland (Individual(s) Involved: Self): Research Grant or Support; Thermo Fisher Scientific (Individual(s) Involved: Self): Research Grant or Support; Tufts Medical Center (Individual(s) Involved: Self): Research Grant or Support; Universite de Sherbrooke (Individual(s) Involved: Self): Research Grant or Support; University of Iowa (Individual(s) Involved: Self): Research Grant or Support; University of Iowa Hospitals and Clinics (Individual(s) Involved: Self): Research Grant or Support; University of Wisconsin (Individual(s) Involved: Self): Research Grant or Support; UNT System College of Pharmacy (Individual(s) Involved: Self): Research Grant or Support; URMC (Individual(s) Involved: Self): Research Grant or Support; UT Southwestern (Individual(s) Involved: Self): Research Grant or Support; VenatoRx (Individual(s) Involved: Self): Research Grant or Support; Viosera Therapeutics (Individual(s) Involved: Self): Research Grant or Support; Wayne State University (Individual(s) Involved: Self): Research Grant or Support

1062. Analysis of Resistance to Oral Standard of Care Antibiotics for Urinary Tract Infections Caused By Escherichia coli and Staphylococcus saprophyticus Collected Worldwide between 2019-2020

Background

Gepotidacin (GSK2140944) is a novel triazaacenaphthylene bacterial type II topoisomerase inhibitor under development for the treatment of gonorrhea and uncomplicated urinary tract infections (UTI). This study reports on the in vitro activity of gepotidacin and other oral antibiotics when tested against contemporary Escherichia coli and Staphylococcus saprophyticus clinical isolates collected from patients with UTIs for a gepotidacin uUTI global surveillance study as a part of the SENTRY Antimicrobial Surveillance Program.

Methods

A total of 3,562 E. coli and 344 S. saprophyticus isolates were collected between 2019 and 2020 from 92 medical centers located in 25 countries. Most isolates (68%) tested were cultured from urine specimens collected from patients seen in ambulatory, emergency, family practice, and outpatient medical services. Bacterial identifications were confirmed by MALDI-TOF. Isolates were tested for susceptibility by CLSI methods at a central laboratory (JMI Laboratories). MIC results for oral antibiotics licensed for the treatment of uUTI and drug-resistant subsets were interpreted per CLSI guidelines.

Results

Gepotidacin (MIC_50/90, 2/2 mg/L) displayed good activity against 3,562 E. coli isolates, with 98.0% of all observed gepotidacin MICs ≤4 mg/L (Table). Susceptibility (S) rates for the other oral agents tested against these isolates were: amoxicillin-clavulanate (79.6% S), ampicillin (45.6% S), ciprofloxacin (72.5%S), fosfomycin (99.0% S), mecillinam (94.1%S), nitrofurantoin (97.3% S), and trimethoprim-sulfamethoxazole (68.2% S). When tested against the drug-resistant subsets, gepotidacin maintained similar MIC_50/90 values (2/4 mg/L), except against isolates resistant to fosfomycin (2/8 mg/L). Against S. saprophyticus isolates, gepotidacin (MIC_50/90, 0.06/0.12 mg/L) inhibited all isolates at ≤0.25 mg/L. Most oral agents showed S results of >97% against S. saprophyticus isolates, except for penicillin (3.5%S).

Conclusion

Gepotidacin demonstrated potent in vitro activity against contemporary E. coli and S. saprophyticus urine isolates. This activity was largely unaffected among isolates demonstrating drug-resistance to other oral standard of care antibiotics.

Table

Disclosures

S J Ryan Arends, PhD, AbbVie (formerly Allergan) (Research Grant or Support)GlaxoSmithKline, LLC (Research Grant or Support)Melinta Therapeutics, LLC (Research Grant or Support)Nabriva Therapeutics (Research Grant or Support)Spero Therapeutics (Research Grant or Support) Deborah Butler, n/a, GlaxoSmithKline, LLC (Employee) Nicole Scangarella-Oman, MS, GlaxoSmithKline, LLC (Employee) Lindsey Paustian, BS (ASCP), GlaxoSmithKline, LLC (Research Grant or Support) Jennifer M. Streit, BS, GlaxoSmithKline, LLC (Research Grant or Support)Melinta Therapeutics, LLC (Research Grant or Support)Shionogi (Research Grant or Support)Spero Therapeutics (Research Grant or Support) Rodrigo E. Mendes, PhD, AbbVie (Research Grant or Support)AbbVie (formerly Allergan) (Research Grant or Support)Cipla Therapeutics (Research Grant or Support)Cipla USA Inc. (Research Grant or Support)ContraFect Corporation (Research Grant or Support)GlaxoSmithKline, LLC (Research Grant or Support)Melinta Therapeutics, Inc. (Research Grant or Support)Melinta Therapeutics, LLC (Research Grant or Support)Nabriva Therapeutics (Research Grant or Support)Pfizer, Inc. (Research Grant or Support)Shionogi (Research Grant or Support)Spero Therapeutics (Research Grant or Support)

1232. In Vitro Activity of Cefiderocol and Comparator Agents against Molecularly characterized Carbapenem-resistant Enterobacterales Clinical Isolates Causing Infection in United States Hospitals (2020)

Background

Cefiderocol (CFDC) represents a new addition to the antimicrobial armamentarium with broad activity against Gram-negative bacteria (GNB). CFDC remains stable to hydrolysis in the presence of serine β-lactamases (ESBLs, KPC and OXA-type carbapenemases) and metallo-β-lactamases. The CFDC and comparator activities were analyzed against Enterobacterales (ENT), including molecularly characterized carbapenem-resistant isolates (CRE), as a part of the SENTRY Antimicrobial Surveillance Program in the USA.

Methods

4,053 ENT were collected from 31 sites in 2020. Susceptibility testing was performed by broth microdilution and CFDC testing used iron-depleted media. CLSI/FDA breakpoints were used. Isolates displaying MIC values ≥4 µg/mL for imipenem (excluded for P. mirabilis, P. penneri and indole-positive Proteus) or meropenem (MER) were subjected to genome sequencing and screening of β-lactamase genes.

Results

A total of 36 (0.9%) CRE were detected, and represented mostly by isolates carrying blaKPC (75.0%; 27/36; Table). A small number of ENT (11.1%; 4/36) carried other carbapenemase genes (1 each of blaNDM-1, blaNDM-5, blaOXA-232, and blaSME-2), whereas 13.9% (5/36) of isolates did not carry any known carbapenemases. CFDC (99.8% susceptible [S]), imipenem-relebactam (IMR; 99.7-99.9%S), meropenem-vaborbactam (MEV; 99.9-100%S), ceftazidime-avibactam (CZA; 99.9-100%S), and MER (99.1-99.9%S) were active against all ENT and the non-CRE subset. CFDC (MIC50/90, 0.5/4 µg/mL; 97.2%S) and CZA (MIC50/90, 1/8 µg/mL; 94.4%S) were the most active agents against CRE, whereas CFDC, IMR, MEV and CZA were active (100%S) against the KPC subset. Finally, CFDC (MIC, 0.5-4 µg/mL; 100%S) was the most active agent against ENT carrying genes other than blaKPC, whereas CZA (1-8 µg/mL; 100%S) was most active against CRE with no known carbapenemases, followed by CFDC (0.5-8 µg/mL; 80.0%S).

Conclusion

The CFDC activity was consistent, regardless of phenotypes or genotypes, including against isolates carrying genes other than blaKPC, where approved β-lactam/β-lactamase inhibitor combinations showed limited activity. These data confirm CFDC as an important option for the treatment of infections caused by ENT and resistant subsets.

Table

Disclosures

Rodrigo E. Mendes, PhD, AbbVie (Research Grant or Support)AbbVie (formerly Allergan) (Research Grant or Support)Cipla Therapeutics (Research Grant or Support)Cipla USA Inc. (Research Grant or Support)ContraFect Corporation (Research Grant or Support)GlaxoSmithKline, LLC (Research Grant or Support)Melinta Therapeutics, Inc. (Research Grant or Support)Melinta Therapeutics, LLC (Research Grant or Support)Nabriva Therapeutics (Research Grant or Support)Pfizer, Inc. (Research Grant or Support)Shionogi (Research Grant or Support)Spero Therapeutics (Research Grant or Support) Timothy B. Doyle, AbbVie (formerly Allergan) (Research Grant or Support)Bravos Biosciences (Research Grant or Support)GlaxoSmithKline (Research Grant or Support)Melinta Therapeutics, Inc. (Research Grant or Support)Pfizer, Inc. (Research Grant or Support)Shionogi (Research Grant or Support)Spero Therapeutics (Research Grant or Support) Dee Shortridge, PhD, AbbVie (formerly Allergan) (Research Grant or Support)Melinta Therapeutics, Inc. (Research Grant or Support)Melinta Therapeutics, LLC (Research Grant or Support)Shionogi (Research Grant or Support) Helio S. Sader, MD, PhD, FIDSA, AbbVie (formerly Allergan) (Research Grant or Support)Basilea Pharmaceutica International, Ltd. (Research Grant or Support)Cipla Therapeutics (Research Grant or Support)Cipla USA Inc. (Research Grant or Support)Department of Health and Human Services (Research Grant or Support, Contract no. HHSO100201600002C)Melinta Therapeutics, LLC (Research Grant or Support)Nabriva Therapeutics (Research Grant or Support)Pfizer, Inc. (Research Grant or Support)Shionogi (Research Grant or Support)Spero Therapeutics (Research Grant or Support) Jennifer M. Streit, BS, GlaxoSmithKline, LLC (Research Grant or Support)Melinta Therapeutics, LLC (Research Grant or Support)Shionogi (Research Grant or Support)Spero Therapeutics (Research Grant or Support) Mariana Castanheira, PhD, AbbVie (formerly Allergan) (Research Grant or Support)Bravos Biosciences (Research Grant or Support)Cidara Therapeutics, Inc. (Research Grant or Support)Cipla Therapeutics (Research Grant or Support)Cipla USA Inc. (Research Grant or Support)GlaxoSmithKline (Research Grant or Support)Melinta Therapeutics, Inc. (Research Grant or Support)Melinta Therapeutics, LLC (Research Grant or Support)Pfizer, Inc. (Research Grant or Support)Qpex Biopharma (Research Grant or Support)Shionogi (Research Grant or Support)Spero Therapeutics (Research Grant or Support) Mariana Castanheira, PhD, Affinity Biosensors (Individual(s) Involved: Self): Research Grant or Support; Allergan (Individual(s) Involved: Self): Research Grant or Support; Amicrobe, Inc (Individual(s) Involved: Self): Research Grant or Support; Amplyx Pharma (Individual(s) Involved: Self): Research Grant or Support; Artugen Therapeutics USA, Inc. (Individual(s) Involved: Self): Research Grant or Support; Astellas (Individual(s) Involved: Self): Research Grant or Support; Basilea (Individual(s) Involved: Self): Research Grant or Support; Beth Israel Deaconess Medical Center (Individual(s) Involved: Self): Research Grant or Support; BIDMC (Individual(s) Involved: Self): Research Grant or Support; bioMerieux Inc. (Individual(s) Involved: Self): Research Grant or Support; BioVersys Ag (Individual(s) Involved: Self): Research Grant or Support; Bugworks (Individual(s) Involved: Self): Research Grant or Support; Cidara (Individual(s) Involved: Self): Research Grant or Support; Cipla (Individual(s) Involved: Self): Research Grant or Support; Contrafect (Individual(s) Involved: Self): Research Grant or Support; Cormedix (Individual(s) Involved: Self): Research Grant or Support; Crestone, Inc. (Individual(s) Involved: Self): Research Grant or Support; Curza (Individual(s) Involved: Self): Research Grant or Support; CXC7 (Individual(s) Involved: Self): Research Grant or Support; Entasis (Individual(s) Involved: Self): Research Grant or Support; Fedora Pharmaceutical (Individual(s) Involved: Self): Research Grant or Support; Fimbrion Therapeutics (Individual(s) Involved: Self): Research Grant or Support; Fox Chase (Individual(s) Involved: Self): Research Grant or Support; GlaxoSmithKline (Individual(s) Involved: Self): Research Grant or Support; Guardian Therapeutics (Individual(s) Involved: Self): Research Grant or Support; Hardy Diagnostics (Individual(s) Involved: Self): Research Grant or Support; IHMA (Individual(s) Involved: Self): Research Grant or Support; Janssen Research & Development (Individual(s) Involved: Self): Research Grant or Support; Johnson & Johnson (Individual(s) Involved: Self): Research Grant or Support; Kaleido Biosceinces (Individual(s) Involved: Self): Research Grant or Support; KBP Biosciences (Individual(s) Involved: Self): Research Grant or Support; Luminex (Individual(s) Involved: Self): Research Grant or Support; Matrivax (Individual(s) Involved: Self): Research Grant or Support; Mayo Clinic (Individual(s) Involved: Self): Research Grant or Support; Medpace (Individual(s) Involved: Self): Research Grant or Support; Meiji Seika Pharma Co., Ltd. (Individual(s) Involved: Self): Research Grant or Support; Melinta (Individual(s) Involved: Self): Research Grant or Support; Menarini (Individual(s) Involved: Self): Research Grant or Support; Merck (Individual(s) Involved: Self): Research Grant or Support; Meridian Bioscience Inc. (Individual(s) Involved: Self): Research Grant or Support; Micromyx (Individual(s) Involved: Self): Research Grant or Support; MicuRx (Individual(s) Involved: Self): Research Grant or Support; N8 Medical (Individual(s) Involved: Self): Research Grant or Support; Nabriva (Individual(s) Involved: Self): Research Grant or Support; National Institutes of Health (Individual(s) Involved: Self): Research Grant or Support; National University of Singapore (Individual(s) Involved: Self): Research Grant or Support; North Bristol NHS Trust (Individual(s) Involved: Self): Research Grant or Support; Novome Biotechnologies (Individual(s) Involved: Self): Research Grant or Support; Paratek (Individual(s) Involved: Self): Research Grant or Support; Pfizer (Individual(s) Involved: Self): Research Grant or Support; Prokaryotics Inc. (Individual(s) Involved: Self): Research Grant or Support; QPEX Biopharma (Individual(s) Involved: Self): Research Grant or Support; Rhode Island Hospital (Individual(s) Involved: Self): Research Grant or Support; RIHML (Individual(s) Involved: Self): Research Grant or Support; Roche (Individual(s) Involved: Self): Research Grant or Support; Roivant (Individual(s) Involved: Self): Research Grant or Support; Salvat (Individual(s) Involved: Self): Research Grant or Support; Scynexis (Individual(s) Involved: Self): Research Grant or Support; SeLux Diagnostics (Individual(s) Involved: Self): Research Grant or Support; Shionogi (Individual(s) Involved: Self): Research Grant or Support; Specific Diagnostics (Individual(s) Involved: Self): Research Grant or Support; Spero (Individual(s) Involved: Self): Research Grant or Support; SuperTrans Medical LT (Individual(s) Involved: Self): Research Grant or Support; T2 Biosystems (Individual(s) Involved: Self): Research Grant or Support; The University of Queensland (Individual(s) Involved: Self): Research Grant or Support; Thermo Fisher Scientific (Individual(s) Involved: Self): Research Grant or Support; Tufts Medical Center (Individual(s) Involved: Self): Research Grant or Support; Universite de Sherbrooke (Individual(s) Involved: Self): Research Grant or Support; University of Iowa (Individual(s) Involved: Self): Research Grant or Support; University of Iowa Hospitals and Clinics (Individual(s) Involved: Self): Research Grant or Support; University of Wisconsin (Individual(s) Involved: Self): Research Grant or Support; UNT System College of Pharmacy (Individual(s) Involved: Self): Research Grant or Support; URMC (Individual(s) Involved: Self): Research Grant or Support; UT Southwestern (Individual(s) Involved: Self): Research Grant or Support; VenatoRx (Individual(s) Involved: Self): Research Grant or Support; Viosera Therapeutics (Individual(s) Involved: Self): Research Grant or Support; Wayne State University (Individual(s) Involved: Self): Research Grant or Support

1272. Cefiderocol In Vitro Activity Against Molecularly Characterized Acinetobacter baumannii-calcoaceticus Complex and Pseudomonas aeruginosa Clinical Isolates Causing Infection in United States Hospitals (2020)

Background

Cefiderocol (CFDC) is a novel siderophore-conjugated cephalosporin with broad activity against aerobic, nonfastidious Gram-negative bacteria. CFDC and comparator activities were analyzed against molecularly characterized A. baumannii-calcoaceticus complex (ACB) and P. aeruginosa (PSA), as a part of the SENTRY Antimicrobial Surveillance Program in the USA.

Methods

248 ACB and 1,069 PSA were consecutively collected from 30 sites in 2020. Susceptibility was performed by broth microdilution and CFDC testing used iron-depleted media. FDA and CLSI breakpoints were used for CFDC. CLSI criteria were applied to comparators, except for imipenem-relebactam (IMR) that used FDA breakpoints. ACB and PSA with imipenem and/or meropenem (MER) MIC ≥4 μg/mL or ceftazidime (CAZ) and/or cefepime MIC ≥16 μg/mL were subjected to next-generation genome sequencing for screening for acquired extended-spectrum β-lactamase (ESBL) and carbapenemase genes.

Results

33.0% of PSA met the MIC screening criteria, and ESBL or carbapenemase genes were not detected among these isolates, except for 1 strain with blaIMP-1. CFDC (97.7-100% susceptible [S]) had similar MIC50 (0.12 μg/mL) and MIC90 (0.25-0.5 μg/mL) values against both PSA populations, as did IMR (91.8-100%S). An MIC of 1 μg/mL was noted for CFDC against the single blaIMP-1-carrying isolate, whereas other agents had MIC values &gt;8 μg/mL (Table). CFDC (MIC50/90, 0.25/2 μg/mL) had the lowest MIC against ACB that met the MIC screening criteria, whereas CFDC, IMR, MER and CAZ were active (99.2-100%S) against MIC screen negative ACB. CFDC (MIC50/90, 0.25/2 μg/mL; 86.7-96.7%S) and IMR (MIC50/90, 0.25/1 μg/mL; 90.0%S) were the most active agents against ACB where only blaOXA-51 and variant genes were noted. CFDC was the only agent active (93.9-100%S; CLSI criteria) against ACB carrying blaOXA-23 (MIC50/90, 0.5/4 μg/mL), blaOXA-24 (MIC50/90, 0.25/1 μg/mL) or other genes (MIC50, 1 μg/mL).

Conclusion

Acquired ESBL and carbapenemase genes remained rare among multidrug-resistant PSA in USA hospitals, whereas acquired blaOXA carbapenemase were prevalent among ACB. CFDC showed potent activity against PSA subsets, as well as across molecularly characterized subsets of ACB, where treatment options were limited.

Disclosures

Rodrigo E. Mendes, PhD, AbbVie (Research Grant or Support)AbbVie (formerly Allergan) (Research Grant or Support)Cipla Therapeutics (Research Grant or Support)Cipla USA Inc. (Research Grant or Support)ContraFect Corporation (Research Grant or Support)GlaxoSmithKline, LLC (Research Grant or Support)Melinta Therapeutics, Inc. (Research Grant or Support)Melinta Therapeutics, LLC (Research Grant or Support)Nabriva Therapeutics (Research Grant or Support)Pfizer, Inc. (Research Grant or Support)Shionogi (Research Grant or Support)Spero Therapeutics (Research Grant or Support) Timothy B. Doyle, AbbVie (formerly Allergan) (Research Grant or Support)Bravos Biosciences (Research Grant or Support)GlaxoSmithKline (Research Grant or Support)Melinta Therapeutics, Inc. (Research Grant or Support)Pfizer, Inc. (Research Grant or Support)Shionogi (Research Grant or Support)Spero Therapeutics (Research Grant or Support) Dee Shortridge, PhD, AbbVie (formerly Allergan) (Research Grant or Support)Melinta Therapeutics, Inc. (Research Grant or Support)Melinta Therapeutics, LLC (Research Grant or Support)Shionogi (Research Grant or Support) Helio S. Sader, MD, PhD, FIDSA, AbbVie (formerly Allergan) (Research Grant or Support)Basilea Pharmaceutica International, Ltd. (Research Grant or Support)Cipla Therapeutics (Research Grant or Support)Cipla USA Inc. (Research Grant or Support)Department of Health and Human Services (Research Grant or Support, Contract no. HHSO100201600002C)Melinta Therapeutics, LLC (Research Grant or Support)Nabriva Therapeutics (Research Grant or Support)Pfizer, Inc. (Research Grant or Support)Shionogi (Research Grant or Support)Spero Therapeutics (Research Grant or Support) Jennifer M. Streit, BS, GlaxoSmithKline, LLC (Research Grant or Support)Melinta Therapeutics, LLC (Research Grant or Support)Shionogi (Research Grant or Support)Spero Therapeutics (Research Grant or Support) Mariana Castanheira, PhD, AbbVie (formerly Allergan) (Research Grant or Support)Bravos Biosciences (Research Grant or Support)Cidara Therapeutics, Inc. (Research Grant or Support)Cipla Therapeutics (Research Grant or Support)Cipla USA Inc. (Research Grant or Support)GlaxoSmithKline (Research Grant or Support)Melinta Therapeutics, Inc. (Research Grant or Support)Melinta Therapeutics, LLC (Research Grant or Support)Pfizer, Inc. (Research Grant or Support)Qpex Biopharma (Research Grant or Support)Shionogi (Research Grant or Support)Spero Therapeutics (Research Grant or Support) Mariana Castanheira, PhD, Affinity Biosensors (Individual(s) Involved: Self): Research Grant or Support; Allergan (Individual(s) Involved: Self): Research Grant or Support; Amicrobe, Inc (Individual(s) Involved: Self): Research Grant or Support; Amplyx Pharma (Individual(s) Involved: Self): Research Grant or Support; Artugen Therapeutics USA, Inc. (Individual(s) Involved: Self): Research Grant or Support; Astellas (Individual(s) Involved: Self): Research Grant or Support; Basilea (Individual(s) Involved: Self): Research Grant or Support; Beth Israel Deaconess Medical Center (Individual(s) Involved: Self): Research Grant or Support; BIDMC (Individual(s) Involved: Self): Research Grant or Support; bioMerieux Inc. (Individual(s) Involved: Self): Research Grant or Support; BioVersys Ag (Individual(s) Involved: Self): Research Grant or Support; Bugworks (Individual(s) Involved: Self): Research Grant or Support; Cidara (Individual(s) Involved: Self): Research Grant or Support; Cipla (Individual(s) Involved: Self): Research Grant or Support; Contrafect (Individual(s) Involved: Self): Research Grant or Support; Cormedix (Individual(s) Involved: Self): Research Grant or Support; Crestone, Inc. (Individual(s) Involved: Self): Research Grant or Support; Curza (Individual(s) Involved: Self): Research Grant or Support; CXC7 (Individual(s) Involved: Self): Research Grant or Support; Entasis (Individual(s) Involved: Self): Research Grant or Support; Fedora Pharmaceutical (Individual(s) Involved: Self): Research Grant or Support; Fimbrion Therapeutics (Individual(s) Involved: Self): Research Grant or Support; Fox Chase (Individual(s) Involved: Self): Research Grant or Support; GlaxoSmithKline (Individual(s) Involved: Self): Research Grant or Support; Guardian Therapeutics (Individual(s) Involved: Self): Research Grant or Support; Hardy Diagnostics (Individual(s) Involved: Self): Research Grant or Support; IHMA (Individual(s) Involved: Self): Research Grant or Support; Janssen Research & Development (Individual(s) Involved: Self): Research Grant or Support; Johnson & Johnson (Individual(s) Involved: Self): Research Grant or Support; Kaleido Biosceinces (Individual(s) Involved: Self): Research Grant or Support; KBP Biosciences (Individual(s) Involved: Self): Research Grant or Support; Luminex (Individual(s) Involved: Self): Research Grant or Support; Matrivax (Individual(s) Involved: Self): Research Grant or Support; Mayo Clinic (Individual(s) Involved: Self): Research Grant or Support; Medpace (Individual(s) Involved: Self): Research Grant or Support; Meiji Seika Pharma Co., Ltd. (Individual(s) Involved: Self): Research Grant or Support; Melinta (Individual(s) Involved: Self): Research Grant or Support; Menarini (Individual(s) Involved: Self): Research Grant or Support; Merck (Individual(s) Involved: Self): Research Grant or Support; Meridian Bioscience Inc. (Individual(s) Involved: Self): Research Grant or Support; Micromyx (Individual(s) Involved: Self): Research Grant or Support; MicuRx (Individual(s) Involved: Self): Research Grant or Support; N8 Medical (Individual(s) Involved: Self): Research Grant or Support; Nabriva (Individual(s) Involved: Self): Research Grant or Support; National Institutes of Health (Individual(s) Involved: Self): Research Grant or Support; National University of Singapore (Individual(s) Involved: Self): Research Grant or Support; North Bristol NHS Trust (Individual(s) Involved: Self): Research Grant or Support; Novome Biotechnologies (Individual(s) Involved: Self): Research Grant or Support; Paratek (Individual(s) Involved: Self): Research Grant or Support; Pfizer (Individual(s) Involved: Self): Research Grant or Support; Prokaryotics Inc. (Individual(s) Involved: Self): Research Grant or Support; QPEX Biopharma (Individual(s) Involved: Self): Research Grant or Support; Rhode Island Hospital (Individual(s) Involved: Self): Research Grant or Support; RIHML (Individual(s) Involved: Self): Research Grant or Support; Roche (Individual(s) Involved: Self): Research Grant or Support; Roivant (Individual(s) Involved: Self): Research Grant or Support; Salvat (Individual(s) Involved: Self): Research Grant or Support; Scynexis (Individual(s) Involved: Self): Research Grant or Support; SeLux Diagnostics (Individual(s) Involved: Self): Research Grant or Support; Shionogi (Individual(s) Involved: Self): Research Grant or Support; Specific Diagnostics (Individual(s) Involved: Self): Research Grant or Support; Spero (Individual(s) Involved: Self): Research Grant or Support; SuperTrans Medical LT (Individual(s) Involved: Self): Research Grant or Support; T2 Biosystems (Individual(s) Involved: Self): Research Grant or Support; The University of Queensland (Individual(s) Involved: Self): Research Grant or Support; Thermo Fisher Scientific (Individual(s) Involved: Self): Research Grant or Support; Tufts Medical Center (Individual(s) Involved: Self): Research Grant or Support; Universite de Sherbrooke (Individual(s) Involved: Self): Research Grant or Support; University of Iowa (Individual(s) Involved: Self): Research Grant or Support; University of Iowa Hospitals and Clinics (Individual(s) Involved: Self): Research Grant or Support; University of Wisconsin (Individual(s) Involved: Self): Research Grant or Support; UNT System College of Pharmacy (Individual(s) Involved: Self): Research Grant or Support; URMC (Individual(s) Involved: Self): Research Grant or Support; UT Southwestern (Individual(s) Involved: Self): Research Grant or Support; VenatoRx (Individual(s) Involved: Self): Research Grant or Support; Viosera Therapeutics (Individual(s) Involved: Self): Research Grant or Support; Wayne State University (Individual(s) Involved: Self): Research Grant or Support

1308. Activity of Cefiderocol and Comparators against Gram-negative Isolates from US Patients Hospitalized with Pneumonia

Background

Cefiderocol (CFDC) is a novel siderophore-conjugated cephalosporin with broad activity against Gram-negative (GN) bacteria, including carbapenem-resistant isolates, and non-fermentative organisms. CFDC is approved by the FDA for complicated urinary tract infection (cUTI), hospital-acquired bacterial pneumonia, and ventilator-associated bacterial pneumonia. In this study, we analyzed the susceptibility of CFDC and comparators against aerobic nonfastidious GN isolates collected from US patients hospitalized with pneumonia (PHP) in 2020 as a part of the SENTRY Antimicrobial Surveillance Program.

Methods

A total of 1,877 Gram-negative isolates were consecutively collected from PHP in 27 US hospitals during 2020. Susceptibility (S) testing was performed using the CLSI broth microdilution method. CFDC was tested in iron-depleted Mueller-Hinton broth. CLSI or FDA (2021) breakpoints were used. Both CLSI and FDA (2021) interpretations are shown in the table. Carbapenem-resistant Enterobacterales (CRE, nonsusceptible to imipenem and/or meropenem) and extensively drug resistant (XDR, susceptible to ≤ 2 drug classes) phenotype isolates were analyzed.

Results

The most common GN organism isolated from PHP was Pseudomonas aeruginosa (PSA, n=570), followed by Klebsiella pneumoniae (n=239). The %S and MIC50/90 values of CFDC for both CLSI and FDA breakpoints and comparators are shown in the table for all organisms and resistant subsets. For Enterobacterales, all tested drugs had &gt;99%S. The 18 CRE isolates had 94.4%S to CFDC and ceftazidime-avibactam. CFDC was the most active antimicrobial tested against PSA (99.3/98.4%S, CLSI/FDA) and XDR PSA (94.6/93.2%). CFDC had the highest %S against Acinetobacter baumannii-calcoaceticus species complex (ABC, 97.0/93.1%S, CLSI/FDA), XDR ABC (94.6/93.2%), and against Stenotrophomonas maltophilia (SM; 100.0/97.1%S, CLSI 2020/2022).

Conclusion

CFDC was highly active against US GN isolates from PHP, including CRE, XDR PSA and ABC, as well as SM. These in vitro results suggest that CFDC may be an important option for the treatment of PHP caused by GN organisms, particularly for pathogens which have few treatment options.

Disclosures

Dee Shortridge, PhD, AbbVie (formerly Allergan) (Research Grant or Support)Melinta Therapeutics, Inc. (Research Grant or Support)Melinta Therapeutics, LLC (Research Grant or Support)Shionogi (Research Grant or Support) Jennifer M. Streit, BS, GlaxoSmithKline, LLC (Research Grant or Support)Melinta Therapeutics, LLC (Research Grant or Support)Shionogi (Research Grant or Support)Spero Therapeutics (Research Grant or Support) Leonard R. Duncan, PhD, AbbVie (formerly Allergan) (Research Grant or Support)Basilea Pharmaceutica International, Ltd. (Research Grant or Support)Cipla Therapeutics (Research Grant or Support)Cipla USA Inc. (Research Grant or Support)Department of Health and Human Services (Research Grant or Support, Contract no. HHSO100201600002C)Shionogi (Research Grant or Support) Mariana Castanheira, PhD, AbbVie (formerly Allergan) (Research Grant or Support)Bravos Biosciences (Research Grant or Support)Cidara Therapeutics, Inc. (Research Grant or Support)Cipla Therapeutics (Research Grant or Support)Cipla USA Inc. (Research Grant or Support)GlaxoSmithKline (Research Grant or Support)Melinta Therapeutics, Inc. (Research Grant or Support)Melinta Therapeutics, LLC (Research Grant or Support)Pfizer, Inc. (Research Grant or Support)Qpex Biopharma (Research Grant or Support)Shionogi (Research Grant or Support)Spero Therapeutics (Research Grant or Support) Mariana Castanheira, PhD, Affinity Biosensors (Individual(s) Involved: Self): Research Grant or Support; Allergan (Individual(s) Involved: Self): Research Grant or Support; Amicrobe, Inc (Individual(s) Involved: Self): Research Grant or Support; Amplyx Pharma (Individual(s) Involved: Self): Research Grant or Support; Artugen Therapeutics USA, Inc. (Individual(s) Involved: Self): Research Grant or Support; Astellas (Individual(s) Involved: Self): Research Grant or Support; Basilea (Individual(s) Involved: Self): Research Grant or Support; Beth Israel Deaconess Medical Center (Individual(s) Involved: Self): Research Grant or Support; BIDMC (Individual(s) Involved: Self): Research Grant or Support; bioMerieux Inc. (Individual(s) Involved: Self): Research Grant or Support; BioVersys Ag (Individual(s) Involved: Self): Research Grant or Support; Bugworks (Individual(s) Involved: Self): Research Grant or Support; Cidara (Individual(s) Involved: Self): Research Grant or Support; Cipla (Individual(s) Involved: Self): Research Grant or Support; Contrafect (Individual(s) Involved: Self): Research Grant or Support; Cormedix (Individual(s) Involved: Self): Research Grant or Support; Crestone, Inc. (Individual(s) Involved: Self): Research Grant or Support; Curza (Individual(s) Involved: Self): Research Grant or Support; CXC7 (Individual(s) Involved: Self): Research Grant or Support; Entasis (Individual(s) Involved: Self): Research Grant or Support; Fedora Pharmaceutical (Individual(s) Involved: Self): Research Grant or Support; Fimbrion Therapeutics (Individual(s) Involved: Self): Research Grant or Support; Fox Chase (Individual(s) Involved: Self): Research Grant or Support; GlaxoSmithKline (Individual(s) Involved: Self): Research Grant or Support; Guardian Therapeutics (Individual(s) Involved: Self): Research Grant or Support; Hardy Diagnostics (Individual(s) Involved: Self): Research Grant or Support; IHMA (Individual(s) Involved: Self): Research Grant or Support; Janssen Research & Development (Individual(s) Involved: Self): Research Grant or Support; Johnson & Johnson (Individual(s) Involved: Self): Research Grant or Support; Kaleido Biosceinces (Individual(s) Involved: Self): Research Grant or Support; KBP Biosciences (Individual(s) Involved: Self): Research Grant or Support; Luminex (Individual(s) Involved: Self): Research Grant or Support; Matrivax (Individual(s) Involved: Self): Research Grant or Support; Mayo Clinic (Individual(s) Involved: Self): Research Grant or Support; Medpace (Individual(s) Involved: Self): Research Grant or Support; Meiji Seika Pharma Co., Ltd. (Individual(s) Involved: Self): Research Grant or Support; Melinta (Individual(s) Involved: Self): Research Grant or Support; Menarini (Individual(s) Involved: Self): Research Grant or Support; Merck (Individual(s) Involved: Self): Research Grant or Support; Meridian Bioscience Inc. (Individual(s) Involved: Self): Research Grant or Support; Micromyx (Individual(s) Involved: Self): Research Grant or Support; MicuRx (Individual(s) Involved: Self): Research Grant or Support; N8 Medical (Individual(s) Involved: Self): Research Grant or Support; Nabriva (Individual(s) Involved: Self): Research Grant or Support; National Institutes of Health (Individual(s) Involved: Self): Research Grant or Support; National University of Singapore (Individual(s) Involved: Self): Research Grant or Support; North Bristol NHS Trust (Individual(s) Involved: Self): Research Grant or Support; Novome Biotechnologies (Individual(s) Involved: Self): Research Grant or Support; Paratek (Individual(s) Involved: Self): Research Grant or Support; Pfizer (Individual(s) Involved: Self): Research Grant or Support; Prokaryotics Inc. (Individual(s) Involved: Self): Research Grant or Support; QPEX Biopharma (Individual(s) Involved: Self): Research Grant or Support; Rhode Island Hospital (Individual(s) Involved: Self): Research Grant or Support; RIHML (Individual(s) Involved: Self): Research Grant or Support; Roche (Individual(s) Involved: Self): Research Grant or Support; Roivant (Individual(s) Involved: Self): Research Grant or Support; Salvat (Individual(s) Involved: Self): Research Grant or Support; Scynexis (Individual(s) Involved: Self): Research Grant or Support; SeLux Diagnostics (Individual(s) Involved: Self): Research Grant or Support; Shionogi (Individual(s) Involved: Self): Research Grant or Support; Specific Diagnostics (Individual(s) Involved: Self): Research Grant or Support; Spero (Individual(s) Involved: Self): Research Grant or Support; SuperTrans Medical LT (Individual(s) Involved: Self): Research Grant or Support; T2 Biosystems (Individual(s) Involved: Self): Research Grant or Support; The University of Queensland (Individual(s) Involved: Self): Research Grant or Support; Thermo Fisher Scientific (Individual(s) Involved: Self): Research Grant or Support; Tufts Medical Center (Individual(s) Involved: Self): Research Grant or Support; Universite de Sherbrooke (Individual(s) Involved: Self): Research Grant or Support; University of Iowa (Individual(s) Involved: Self): Research Grant or Support; University of Iowa Hospitals and Clinics (Individual(s) Involved: Self): Research Grant or Support; University of Wisconsin (Individual(s) Involved: Self): Research Grant or Support; UNT System College of Pharmacy (Individual(s) Involved: Self): Research Grant or Support; URMC (Individual(s) Involved: Self): Research Grant or Support; UT Southwestern (Individual(s) Involved: Self): Research Grant or Support; VenatoRx (Individual(s) Involved: Self): Research Grant or Support; Viosera Therapeutics (Individual(s) Involved: Self): Research Grant or Support; Wayne State University (Individual(s) Involved: Self): Research Grant or Support

1057. Tebipenem In vitro Activity Against a Collection of Pathogens Responsible for Urinary Tract Infections in the US

Background

Enterobacterales (ENT)—especially Escherichia coli (EC), Klebsiella pneumoniae (KPN), and Proteus mirabilis (PM)—are widely implicated in urinary tract infections (UTIs). Many oral agents are used to manage UTIs, but their usefulness has been compromised by the increased prevalence of extended-spectrum β-lactamases (ESBL) and presence of co-resistance to trimethoprim-sulfamethoxazole (TMP/SMX) and quinolones. Tebipenem (TBP) is an oral carbapenem in clinical development for treating complicated UTIs and acute pyelonephritis. This study assessed the in vitro activity of TBP and comparator agents against ENT responsible for UTIs in the US during 2019-2020.

Methods

A total of 3,576 ENT recovered from urine samples during the 2019-2020 STEWARD Surveillance Program were included in the study. Isolates were collected from medical centers in all 9 US Census Regions and were centrally tested for susceptibility by reference broth microdilution method. MIC interpretation was performed based on CLSI criteria.

Results

EC comprised 65.6% of all ENT pathogens, followed by KPN (14.3%), PM (6.6%), and other species (13.7%). TBP (MIC90, 0.015-0.06 mg/L) and ertapenem (ERT; MIC90, 0.03 mg/L) showed similar MIC90 results against ENT, EC, and KPN (Table). Ceftazidime (CAZ; MIC90, 8-16 mg/L) had elevated MIC90 values and suboptimal susceptibility results (86.1-89.3%) against ENT, EC, and KPN. The oral agents, cefuroxime, amoxicillin-clavulanate, TMP-SMX, and levofloxacin showed susceptibility rates ranging from 63.1% to 87.1% against ENT, EC, and KPN. TBP (MIC50/90, 0.12/0.12 mg/L) inhibited all PM at ≤0.25 mg/L. PM isolates were susceptible to ERT (100.0%), CAZ (98.7%), cefuroxime (94.4%), and amoxicillin/clavulanate (96.6%), whereas susceptibility rates of 71.8-76.8% were noted for TMP-SMX and levofloxacin.

Conclusion

TBP displayed potent activity against ENT UTI pathogens recovered from patients in the US. TBP demonstrated in vitro activity against these UTI pathogens similar to that of ERT. In addition, these data showed compromised activity of intravenous and oral agents used for treating UTI. This data supports the development of tebipenem as an oral option for management of UTI in the US.

Disclosures

Rodrigo E. Mendes, PhD, AbbVie (Research Grant or Support)AbbVie (formerly Allergan) (Research Grant or Support)Cipla Therapeutics (Research Grant or Support)Cipla USA Inc. (Research Grant or Support)ContraFect Corporation (Research Grant or Support)GlaxoSmithKline, LLC (Research Grant or Support)Melinta Therapeutics, Inc. (Research Grant or Support)Melinta Therapeutics, LLC (Research Grant or Support)Nabriva Therapeutics (Research Grant or Support)Pfizer, Inc. (Research Grant or Support)Shionogi (Research Grant or Support)Spero Therapeutics (Research Grant or Support) Ian A. Critchley, Ph.D., Spero Therapeutics (Employee, Shareholder) Nicole Cotroneo, Spero Therapeutics (Employee, Shareholder) Jennifer M. Streit, BS, GlaxoSmithKline, LLC (Research Grant or Support)Melinta Therapeutics, LLC (Research Grant or Support)Shionogi (Research Grant or Support)Spero Therapeutics (Research Grant or Support) Helio S. Sader, MD, PhD, FIDSA, AbbVie (formerly Allergan) (Research Grant or Support)Basilea Pharmaceutica International, Ltd. (Research Grant or Support)Cipla Therapeutics (Research Grant or Support)Cipla USA Inc. (Research Grant or Support)Department of Health and Human Services (Research Grant or Support, Contract no. HHSO100201600002C)Melinta Therapeutics, LLC (Research Grant or Support)Nabriva Therapeutics (Research Grant or Support)Pfizer, Inc. (Research Grant or Support)Shionogi (Research Grant or Support)Spero Therapeutics (Research Grant or Support) Mariana Castanheira, PhD, AbbVie (formerly Allergan) (Research Grant or Support)Bravos Biosciences (Research Grant or Support)Cidara Therapeutics, Inc. (Research Grant or Support)Cipla Therapeutics (Research Grant or Support)Cipla USA Inc. (Research Grant or Support)GlaxoSmithKline (Research Grant or Support)Melinta Therapeutics, Inc. (Research Grant or Support)Melinta Therapeutics, LLC (Research Grant or Support)Pfizer, Inc. (Research Grant or Support)Qpex Biopharma (Research Grant or Support)Shionogi (Research Grant or Support)Spero Therapeutics (Research Grant or Support) Mariana Castanheira, PhD, Affinity Biosensors (Individual(s) Involved: Self): Research Grant or Support; Allergan (Individual(s) Involved: Self): Research Grant or Support; Amicrobe, Inc (Individual(s) Involved: Self): Research Grant or Support; Amplyx Pharma (Individual(s) Involved: Self): Research Grant or Support; Artugen Therapeutics USA, Inc. (Individual(s) Involved: Self): Research Grant or Support; Astellas (Individual(s) Involved: Self): Research Grant or Support; Basilea (Individual(s) Involved: Self): Research Grant or Support; Beth Israel Deaconess Medical Center (Individual(s) Involved: Self): Research Grant or Support; BIDMC (Individual(s) Involved: Self): Research Grant or Support; bioMerieux Inc. (Individual(s) Involved: Self): Research Grant or Support; BioVersys Ag (Individual(s) Involved: Self): Research Grant or Support; Bugworks (Individual(s) Involved: Self): Research Grant or Support; Cidara (Individual(s) Involved: Self): Research Grant or Support; Cipla (Individual(s) Involved: Self): Research Grant or Support; Contrafect (Individual(s) Involved: Self): Research Grant or Support; Cormedix (Individual(s) Involved: Self): Research Grant or Support; Crestone, Inc. (Individual(s) Involved: Self): Research Grant or Support; Curza (Individual(s) Involved: Self): Research Grant or Support; CXC7 (Individual(s) Involved: Self): Research Grant or Support; Entasis (Individual(s) Involved: Self): Research Grant or Support; Fedora Pharmaceutical (Individual(s) Involved: Self): Research Grant or Support; Fimbrion Therapeutics (Individual(s) Involved: Self): Research Grant or Support; Fox Chase (Individual(s) Involved: Self): Research Grant or Support; GlaxoSmithKline (Individual(s) Involved: Self): Research Grant or Support; Guardian Therapeutics (Individual(s) Involved: Self): Research Grant or Support; Hardy Diagnostics (Individual(s) Involved: Self): Research Grant or Support; IHMA (Individual(s) Involved: Self): Research Grant or Support; Janssen Research & Development (Individual(s) Involved: Self): Research Grant or Support; Johnson & Johnson (Individual(s) Involved: Self): Research Grant or Support; Kaleido Biosceinces (Individual(s) Involved: Self): Research Grant or Support; KBP Biosciences (Individual(s) Involved: Self): Research Grant or Support; Luminex (Individual(s) Involved: Self): Research Grant or Support; Matrivax (Individual(s) Involved: Self): Research Grant or Support; Mayo Clinic (Individual(s) Involved: Self): Research Grant or Support; Medpace (Individual(s) Involved: Self): Research Grant or Support; Meiji Seika Pharma Co., Ltd. (Individual(s) Involved: Self): Research Grant or Support; Melinta (Individual(s) Involved: Self): Research Grant or Support; Menarini (Individual(s) Involved: Self): Research Grant or Support; Merck (Individual(s) Involved: Self): Research Grant or Support; Meridian Bioscience Inc. (Individual(s) Involved: Self): Research Grant or Support; Micromyx (Individual(s) Involved: Self): Research Grant or Support; MicuRx (Individual(s) Involved: Self): Research Grant or Support; N8 Medical (Individual(s) Involved: Self): Research Grant or Support; Nabriva (Individual(s) Involved: Self): Research Grant or Support; National Institutes of Health (Individual(s) Involved: Self): Research Grant or Support; National University of Singapore (Individual(s) Involved: Self): Research Grant or Support; North Bristol NHS Trust (Individual(s) Involved: Self): Research Grant or Support; Novome Biotechnologies (Individual(s) Involved: Self): Research Grant or Support; Paratek (Individual(s) Involved: Self): Research Grant or Support; Pfizer (Individual(s) Involved: Self): Research Grant or Support; Prokaryotics Inc. (Individual(s) Involved: Self): Research Grant or Support; QPEX Biopharma (Individual(s) Involved: Self): Research Grant or Support; Rhode Island Hospital (Individual(s) Involved: Self): Research Grant or Support; RIHML (Individual(s) Involved: Self): Research Grant or Support; Roche (Individual(s) Involved: Self): Research Grant or Support; Roivant (Individual(s) Involved: Self): Research Grant or Support; Salvat (Individual(s) Involved: Self): Research Grant or Support; Scynexis (Individual(s) Involved: Self): Research Grant or Support; SeLux Diagnostics (Individual(s) Involved: Self): Research Grant or Support; Shionogi (Individual(s) Involved: Self): Research Grant or Support; Specific Diagnostics (Individual(s) Involved: Self): Research Grant or Support; Spero (Individual(s) Involved: Self): Research Grant or Support; SuperTrans Medical LT (Individual(s) Involved: Self): Research Grant or Support; T2 Biosystems (Individual(s) Involved: Self): Research Grant or Support; The University of Queensland (Individual(s) Involved: Self): Research Grant or Support; Thermo Fisher Scientific (Individual(s) Involved: Self): Research Grant or Support; Tufts Medical Center (Individual(s) Involved: Self): Research Grant or Support; Universite de Sherbrooke (Individual(s) Involved: Self): Research Grant or Support; University of Iowa (Individual(s) Involved: Self): Research Grant or Support; University of Iowa Hospitals and Clinics (Individual(s) Involved: Self): Research Grant or Support; University of Wisconsin (Individual(s) Involved: Self): Research Grant or Support; UNT System College of Pharmacy (Individual(s) Involved: Self): Research Grant or Support; URMC (Individual(s) Involved: Self): Research Grant or Support; UT Southwestern (Individual(s) Involved: Self): Research Grant or Support; VenatoRx (Individual(s) Involved: Self): Research Grant or Support; Viosera Therapeutics (Individual(s) Involved: Self): Research Grant or Support; Wayne State University (Individual(s) Involved: Self): Research Grant or Support

1238. Comparative Activity of Meropenem-Vaborbactam and Ceftazidime-Avibactam Against Multidrug-Resistant Enterobacter cloacae from Hospitals in Europe and United States

Background

Enterobacter spp. are part of the ESKAPE pathogens that have been recognized as a threat to human health. Among this genus, E. cloacae species complex (ECL) is the most common species that causes human infections. ECL can develop resistance to ß-lactams and other antimicrobial classes due to alterations in gene regulatory pathways. We evaluated the activity of meropenem-vaborbactam, ceftazidime-avibactam, and comparator agents against 235 multidrug resistant (MDR) ECL isolates collected in Europe and the US during 2017-2019.

Methods

A total of 2,459 ECL clinical isolates were collected in 40 European and 33 US hospitals. Isolates were susceptibility tested by reference broth microdilution methods and results were interpreted using CLSI, EUCAST, and US FDA breakpoints. MDR was defined as resistant to 3 or more drug classes when applying the CLSI breakpoints.

Results

MDR ECL were observed among 9.6% of the overall isolates. The MDR rate in Europe (12.0%; 155/1,295) was considerably higher than in the US (6.9%; 80/1,164). Meropenem-vaborbactam inhibited 94.5% and 97.4% of the MDR ECL isolates applying CLSI and EUCAST breakpoints, respectively (Table). Meropenem inhibited 77.9%/85.5% of the isolates (CLSI/EUCAST breakpoints). Cefepime inhibited only 26.0%/16.2% of the MDR ECL isolates while piperacillin-tazobactam inhibited only 13.2%/6.4%. Ceftazidime-avibactam inhibited 93.6% of the MDR ECL isolates. Amikacin and tigecycline were the most active non-beta-lactam comparators, inhibiting 91.9% and 80.0% of these isolates using CLSI/US FDA breakpoints. A total of 93.1% of the isolates were intermediate to colistin applying CLSI breakpoints or susceptible using the EUCAST criteria. Meropenem-vaborbactam inhibited 73.5% and 87.8% of the MDR ECL isolates nonsusceptible to meropenem and cefepime, the main therapeutic option against ECL isolates. Ceftazidime-avibactam inhibited 73.5% of these isolates.

Conclusion

In a global surveillance, ECL is the second most common Enterobacterales species/species complex displaying MDR and carbapenem-resistance phenotypes, behind only Klebsiella pneumoniae. Meropenem-vaborbactam and ceftazidime-avibactam can be important options to treat infections caused by MDR ECL.

Disclosures

Mariana Castanheira, PhD, AbbVie (formerly Allergan) (Research Grant or Support)Bravos Biosciences (Research Grant or Support)Cidara Therapeutics, Inc. (Research Grant or Support)Cipla Therapeutics (Research Grant or Support)Cipla USA Inc. (Research Grant or Support)GlaxoSmithKline (Research Grant or Support)Melinta Therapeutics, Inc. (Research Grant or Support)Melinta Therapeutics, LLC (Research Grant or Support)Pfizer, Inc. (Research Grant or Support)Qpex Biopharma (Research Grant or Support)Shionogi (Research Grant or Support)Spero Therapeutics (Research Grant or Support) Mariana Castanheira, PhD, Affinity Biosensors (Individual(s) Involved: Self): Research Grant or Support; Allergan (Individual(s) Involved: Self): Research Grant or Support; Amicrobe, Inc (Individual(s) Involved: Self): Research Grant or Support; Amplyx Pharma (Individual(s) Involved: Self): Research Grant or Support; Artugen Therapeutics USA, Inc. (Individual(s) Involved: Self): Research Grant or Support; Astellas (Individual(s) Involved: Self): Research Grant or Support; Basilea (Individual(s) Involved: Self): Research Grant or Support; Beth Israel Deaconess Medical Center (Individual(s) Involved: Self): Research Grant or Support; BIDMC (Individual(s) Involved: Self): Research Grant or Support; bioMerieux Inc. (Individual(s) Involved: Self): Research Grant or Support; BioVersys Ag (Individual(s) Involved: Self): Research Grant or Support; Bugworks (Individual(s) Involved: Self): Research Grant or Support; Cidara (Individual(s) Involved: Self): Research Grant or Support; Cipla (Individual(s) Involved: Self): Research Grant or Support; Contrafect (Individual(s) Involved: Self): Research Grant or Support; Cormedix (Individual(s) Involved: Self): Research Grant or Support; Crestone, Inc. (Individual(s) Involved: Self): Research Grant or Support; Curza (Individual(s) Involved: Self): Research Grant or Support; CXC7 (Individual(s) Involved: Self): Research Grant or Support; Entasis (Individual(s) Involved: Self): Research Grant or Support; Fedora Pharmaceutical (Individual(s) Involved: Self): Research Grant or Support; Fimbrion Therapeutics (Individual(s) Involved: Self): Research Grant or Support; Fox Chase (Individual(s) Involved: Self): Research Grant or Support; GlaxoSmithKline (Individual(s) Involved: Self): Research Grant or Support; Guardian Therapeutics (Individual(s) Involved: Self): Research Grant or Support; Hardy Diagnostics (Individual(s) Involved: Self): Research Grant or Support; IHMA (Individual(s) Involved: Self): Research Grant or Support; Janssen Research & Development (Individual(s) Involved: Self): Research Grant or Support; Johnson & Johnson (Individual(s) Involved: Self): Research Grant or Support; Kaleido Biosceinces (Individual(s) Involved: Self): Research Grant or Support; KBP Biosciences (Individual(s) Involved: Self): Research Grant or Support; Luminex (Individual(s) Involved: Self): Research Grant or Support; Matrivax (Individual(s) Involved: Self): Research Grant or Support; Mayo Clinic (Individual(s) Involved: Self): Research Grant or Support; Medpace (Individual(s) Involved: Self): Research Grant or Support; Meiji Seika Pharma Co., Ltd. (Individual(s) Involved: Self): Research Grant or Support; Melinta (Individual(s) Involved: Self): Research Grant or Support; Menarini (Individual(s) Involved: Self): Research Grant or Support; Merck (Individual(s) Involved: Self): Research Grant or Support; Meridian Bioscience Inc. (Individual(s) Involved: Self): Research Grant or Support; Micromyx (Individual(s) Involved: Self): Research Grant or Support; MicuRx (Individual(s) Involved: Self): Research Grant or Support; N8 Medical (Individual(s) Involved: Self): Research Grant or Support; Nabriva (Individual(s) Involved: Self): Research Grant or Support; National Institutes of Health (Individual(s) Involved: Self): Research Grant or Support; National University of Singapore (Individual(s) Involved: Self): Research Grant or Support; North Bristol NHS Trust (Individual(s) Involved: Self): Research Grant or Support; Novome Biotechnologies (Individual(s) Involved: Self): Research Grant or Support; Paratek (Individual(s) Involved: Self): Research Grant or Support; Pfizer (Individual(s) Involved: Self): Research Grant or Support; Prokaryotics Inc. (Individual(s) Involved: Self): Research Grant or Support; QPEX Biopharma (Individual(s) Involved: Self): Research Grant or Support; Rhode Island Hospital (Individual(s) Involved: Self): Research Grant or Support; RIHML (Individual(s) Involved: Self): Research Grant or Support; Roche (Individual(s) Involved: Self): Research Grant or Support; Roivant (Individual(s) Involved: Self): Research Grant or Support; Salvat (Individual(s) Involved: Self): Research Grant or Support; Scynexis (Individual(s) Involved: Self): Research Grant or Support; SeLux Diagnostics (Individual(s) Involved: Self): Research Grant or Support; Shionogi (Individual(s) Involved: Self): Research Grant or Support; Specific Diagnostics (Individual(s) Involved: Self): Research Grant or Support; Spero (Individual(s) Involved: Self): Research Grant or Support; SuperTrans Medical LT (Individual(s) Involved: Self): Research Grant or Support; T2 Biosystems (Individual(s) Involved: Self): Research Grant or Support; The University of Queensland (Individual(s) Involved: Self): Research Grant or Support; Thermo Fisher Scientific (Individual(s) Involved: Self): Research Grant or Support; Tufts Medical Center (Individual(s) Involved: Self): Research Grant or Support; Universite de Sherbrooke (Individual(s) Involved: Self): Research Grant or Support; University of Iowa (Individual(s) Involved: Self): Research Grant or Support; University of Iowa Hospitals and Clinics (Individual(s) Involved: Self): Research Grant or Support; University of Wisconsin (Individual(s) Involved: Self): Research Grant or Support; UNT System College of Pharmacy (Individual(s) Involved: Self): Research Grant or Support; URMC (Individual(s) Involved: Self): Research Grant or Support; UT Southwestern (Individual(s) Involved: Self): Research Grant or Support; VenatoRx (Individual(s) Involved: Self): Research Grant or Support; Viosera Therapeutics (Individual(s) Involved: Self): Research Grant or Support; Wayne State University (Individual(s) Involved: Self): Research Grant or Support Jennifer M. Streit, BS, GlaxoSmithKline, LLC (Research Grant or Support)Melinta Therapeutics, LLC (Research Grant or Support)Shionogi (Research Grant or Support)Spero Therapeutics (Research Grant or Support) Helio S. Sader, MD, PhD, FIDSA, AbbVie (formerly Allergan) (Research Grant or Support)Basilea Pharmaceutica International, Ltd. (Research Grant or Support)Cipla Therapeutics (Research Grant or Support)Cipla USA Inc. (Research Grant or Support)Department of Health and Human Services (Research Grant or Support, Contract no. HHSO100201600002C)Melinta Therapeutics, LLC (Research Grant or Support)Nabriva Therapeutics (Research Grant or Support)Pfizer, Inc. (Research Grant or Support)Shionogi (Research Grant or Support)Spero Therapeutics (Research Grant or Support) Dee Shortridge, PhD, AbbVie (formerly Allergan) (Research Grant or Support)Melinta Therapeutics, Inc. (Research Grant or Support)Melinta Therapeutics, LLC (Research Grant or Support)Shionogi (Research Grant or Support)

1369. Oritavancin Activity Against Methicillin-Resistant S. aureus (MRSA) Isolates Causing Skin and Skin Structure Infections in US Hospitals (2017-2019)

Background

MRSA remains an important cause of community-onset (CA) and nosocomial (NA)- SSSI. Oritavancin (ORI) is a lipoglycopeptide antibiotic with activity against S. aureus, including MRSA and multidrug-resistant (MDR) strains. ORI was approved for clinical use by the US FDA to treat ABSSSI with a single 1,200 mg infusion over 1 (Kimyrsa) or 3 (Orbactiv) hours. This study evaluated the activity of ORI against MRSA isolates causing SSSI from US medical centers.

Methods

A total of 3,792 S. aureus isolates were consecutively collected (1 per patient) from 31 medical centers in 2017-2019 and tested for susceptibility (S) to ORI and comparators using CLSI broth microdilution methods. Among 1,582 (41.7%) MRSA isolates, 1,379 (87.2%) were reported as CA-MRSA and 203 (12.8%) as NA-MRSA. CA-MRSA isolates were evaluated by resistance (R) subgroups, including clindamycin (CLI-R; n=283; 20.5%), levofloxacin (LEV-R; n=831; 60.3%), MDR (non-susceptible to ≥3 classes of agents; n=816; 59.2%), and extensively drug resistant (XDR; non-susceptible to ≥5 classes; n=47; 3.4%).

Results

Overall, ORI inhibited 99.9% of all S. aureus isolates at the susceptible breakpoint (≤0.12 mg/L; 99.9% of MSSA and 100% of MRSA; Table). S rates were generally comparable between NA-MRSA and CA-MRSA isolates for ORI (100%S) and linezolid (LZD, 100%S) but lower susceptibility was observed for NA-MRSA compared to CA-MRSA for CLI (71.9%S vs. 79.1%S), LEV (31.0%S vs. 39.4%S), and trimethoprim-sulfamethoxazole (TMP-SMX; 91.1%S vs. 96.9%S). ORI was active against MRSA (MIC50/90, 0.03/0.03 mg/L), regardless of infection status (NA, MIC50/90, 0.03/0.06 mg/L; CA, MIC50/90, 0.03/0.03 mg/L). ORI and LZD remained active (100%S) against all CA-MRSA subsets: CLI-R, LEV-R, MDR, and XDR. Limited activity of CLI (69.9%S) and LEV (13.1%S) was observed against MRSA and each R subset, whereas TMP-SMX had &gt;90%S for all MSSA, MRSA, and R subsets, except XDR.

Conclusion

ORI exhibited potent in vitro activity against MRSA, regardless of the infection onset or R subset, in contrast to many comparators that lack activity against both, CA-MRSA and NA-MRSA. This in vitro activity, combined with the infusion time options provided to clinicians, suggests ORI is a favorable agent for treating SSSI in the US caused by MRSA, including MDR and XDR strains.

Disclosures

Cecilia G. Carvalhaes, MD, PhD, AbbVie (formerly Allergan) (Research Grant or Support)Cidara Therapeutics, Inc. (Research Grant or Support)Cipla Therapeutics (Research Grant or Support)Cipla USA Inc. (Research Grant or Support)Melinta Therapeutics, LLC (Research Grant or Support)Pfizer, Inc. (Research Grant or Support) Helio S. Sader, MD, PhD, FIDSA, AbbVie (formerly Allergan) (Research Grant or Support)Basilea Pharmaceutica International, Ltd. (Research Grant or Support)Cipla Therapeutics (Research Grant or Support)Cipla USA Inc. (Research Grant or Support)Department of Health and Human Services (Research Grant or Support, Contract no. HHSO100201600002C)Melinta Therapeutics, LLC (Research Grant or Support)Nabriva Therapeutics (Research Grant or Support)Pfizer, Inc. (Research Grant or Support)Shionogi (Research Grant or Support)Spero Therapeutics (Research Grant or Support) Dee Shortridge, PhD, AbbVie (formerly Allergan) (Research Grant or Support)Melinta Therapeutics, Inc. (Research Grant or Support)Melinta Therapeutics, LLC (Research Grant or Support)Shionogi (Research Grant or Support) Jennifer M. Streit, BS, GlaxoSmithKline, LLC (Research Grant or Support)Melinta Therapeutics, LLC (Research Grant or Support)Shionogi (Research Grant or Support)Spero Therapeutics (Research Grant or Support) Rodrigo E. Mendes, PhD, AbbVie (Research Grant or Support)AbbVie (formerly Allergan) (Research Grant or Support)Cipla Therapeutics (Research Grant or Support)Cipla USA Inc. (Research Grant or Support)ContraFect Corporation (Research Grant or Support)GlaxoSmithKline, LLC (Research Grant or Support)Melinta Therapeutics, Inc. (Research Grant or Support)Melinta Therapeutics, LLC (Research Grant or Support)Nabriva Therapeutics (Research Grant or Support)Pfizer, Inc. (Research Grant or Support)Shionogi (Research Grant or Support)Spero Therapeutics (Research Grant or Support)

1075. In vitro Activity of Gepotidacin against Escherichia coli Causing Urinary Tract Infections in the United States, Including Molecularly Characterized Fluoroquinolone Resistant Subsets

Background

Gepotidacin (GEP) is a novel bacterial type II topoisomerase inhibitor in Phase 3 clinical trials for the treatment of gonorrhea and uncomplicated urinary tract infections (UTI). This study characterized fluoroquinolone (FQ)-not susceptible (not S) E. coli causing UTI in U.S. patients and evaluated the in vitro activity of GEP and comparators against various drug resistance (R) subsets.

Methods

1,035 E. coli collected from 38 U.S. sites were included as part of the GEP Global UTI Surveillance Program (2019). Isolates were tested for susceptibility by broth microdilution. E. coli with MICs ≥0.5 mg/L for ciprofloxacin (not S) and/or ≥1 mg/L for levofloxacin (not S) were selected for screening of FQ-R mechanisms, and subjected to genome sequencing, followed by screening of FQ-R genes and QRDR mutations in GyrA, GyrB, ParC and ParE.

Results

A total of 26.8% (277/1,035) E. coli met the screening criteria for FQ-not S (Table). Overall, GEP had MIC₉₀ values of 2 mg/L and 4 mg/L against FQ-S and FQ-not S isolates, respectively. Nitrofurantoin had activity against the FQ-S and FQ-not S subsets (98.8% and 94.2%S, respectively), whereas amoxicillin-clavulanate (86.5% and 59.6%S) and trimethoprim-sulfamethoxazole (75.8% and 37.0%S) had limited activity. Most FQ-not S isolates (52.7%; 146/277) had double mutations in GyrA and ParC, followed by those isolates (20.6%; 57/277) with double mutations in GyrA and single mutations in ParC and ParE. The third most common genotype was represented by isolates (14.8%;41/277) with double mutations in GyrA and a single mutation in ParC. GEP had MIC₅₀ values of 1 mg/L or 2 mg/L and MIC₉₀ values of 2 mg/L or 4 mg/L when tested against isolates with various combinations of QRDR mutations. 4.3% (12/277) of FQ-not S E. coli carried qnrB (6) or qnrS (6), and GEP (MIC_50/90, 8/16 mg/L) had MICs of 0.5–32 mg/L against this subset.

Conclusion

GEP demonstrated potent activity against FQ-S and FQ-not S E. coli causing UTI in the U.S. In addition, GEP MIC did not seem to be affected by any combinations of FQ-R genes and QRDR mutations tested, except against the rare presence of qnrB/S genes. These data support the clinical development of GEP as a treatment option for UTI caused by FQ-S and FQ-not S E. coli isolates.

Table

Disclosures

Rodrigo E. Mendes, PhD, AbbVie (Research Grant or Support)AbbVie (formerly Allergan) (Research Grant or Support)Cipla Therapeutics (Research Grant or Support)Cipla USA Inc. (Research Grant or Support)ContraFect Corporation (Research Grant or Support)GlaxoSmithKline, LLC (Research Grant or Support)Melinta Therapeutics, Inc. (Research Grant or Support)Melinta Therapeutics, LLC (Research Grant or Support)Nabriva Therapeutics (Research Grant or Support)Pfizer, Inc. (Research Grant or Support)Shionogi (Research Grant or Support)Spero Therapeutics (Research Grant or Support) Timothy B. Doyle, AbbVie (formerly Allergan) (Research Grant or Support)Bravos Biosciences (Research Grant or Support)GlaxoSmithKline (Research Grant or Support)Melinta Therapeutics, Inc. (Research Grant or Support)Pfizer, Inc. (Research Grant or Support)Shionogi (Research Grant or Support)Spero Therapeutics (Research Grant or Support) S J Ryan Arends, PhD, AbbVie (formerly Allergan) (Research Grant or Support)GlaxoSmithKline, LLC (Research Grant or Support)Melinta Therapeutics, LLC (Research Grant or Support)Nabriva Therapeutics (Research Grant or Support)Spero Therapeutics (Research Grant or Support) Deborah Butler, n/a, GlaxoSmithKline, LLC (Employee) Nicole Scangarella-Oman, MS, GlaxoSmithKline, LLC (Employee) Jennifer M. Streit, BS, GlaxoSmithKline, LLC (Research Grant or Support)Melinta Therapeutics, LLC (Research Grant or Support)Shionogi (Research Grant or Support)Spero Therapeutics (Research Grant or Support) Mariana Castanheira, PhD, AbbVie (formerly Allergan) (Research Grant or Support)Bravos Biosciences (Research Grant or Support)Cidara Therapeutics, Inc. (Research Grant or Support)Cipla Therapeutics (Research Grant or Support)Cipla USA Inc. (Research Grant or Support)GlaxoSmithKline (Research Grant or Support)Melinta Therapeutics, Inc. (Research Grant or Support)Melinta Therapeutics, LLC (Research Grant or Support)Pfizer, Inc. (Research Grant or Support)Qpex Biopharma (Research Grant or Support)Shionogi (Research Grant or Support)Spero Therapeutics (Research Grant or Support) Mariana Castanheira, PhD, Affinity Biosensors (Individual(s) Involved: Self): Research Grant or Support; Allergan (Individual(s) Involved: Self): Research Grant or Support; Amicrobe, Inc (Individual(s) Involved: Self): Research Grant or Support; Amplyx Pharma (Individual(s) Involved: Self): Research Grant or Support; Artugen Therapeutics USA, Inc. (Individual(s) Involved: Self): Research Grant or Support; Astellas (Individual(s) Involved: Self): Research Grant or Support; Basilea (Individual(s) Involved: Self): Research Grant or Support; Beth Israel Deaconess Medical Center (Individual(s) Involved: Self): Research Grant or Support; BIDMC (Individual(s) Involved: Self): Research Grant or Support; bioMerieux Inc. (Individual(s) Involved: Self): Research Grant or Support; BioVersys Ag (Individual(s) Involved: Self): Research Grant or Support; Bugworks (Individual(s) Involved: Self): Research Grant or Support; Cidara (Individual(s) Involved: Self): Research Grant or Support; Cipla (Individual(s) Involved: Self): Research Grant or Support; Contrafect (Individual(s) Involved: Self): Research Grant or Support; Cormedix (Individual(s) Involved: Self): Research Grant or Support; Crestone, Inc. (Individual(s) Involved: Self): Research Grant or Support; Curza (Individual(s) Involved: Self): Research Grant or Support; CXC7 (Individual(s) Involved: Self): Research Grant or Support; Entasis (Individual(s) Involved: Self): Research Grant or Support; Fedora Pharmaceutical (Individual(s) Involved: Self): Research Grant or Support; Fimbrion Therapeutics (Individual(s) Involved: Self): Research Grant or Support; Fox Chase (Individual(s) Involved: Self): Research Grant or Support; GlaxoSmithKline (Individual(s) Involved: Self): Research Grant or Support; Guardian Therapeutics (Individual(s) Involved: Self): Research Grant or Support; Hardy Diagnostics (Individual(s) Involved: Self): Research Grant or Support; IHMA (Individual(s) Involved: Self): Research Grant or Support; Janssen Research & Development (Individual(s) Involved: Self): Research Grant or Support; Johnson & Johnson (Individual(s) Involved: Self): Research Grant or Support; Kaleido Biosceinces (Individual(s) Involved: Self): Research Grant or Support; KBP Biosciences (Individual(s) Involved: Self): Research Grant or Support; Luminex (Individual(s) Involved: Self): Research Grant or Support; Matrivax (Individual(s) Involved: Self): Research Grant or Support; Mayo Clinic (Individual(s) Involved: Self): Research Grant or Support; Medpace (Individual(s) Involved: Self): Research Grant or Support; Meiji Seika Pharma Co., Ltd. (Individual(s) Involved: Self): Research Grant or Support; Melinta (Individual(s) Involved: Self): Research Grant or Support; Menarini (Individual(s) Involved: Self): Research Grant or Support; Merck (Individual(s) Involved: Self): Research Grant or Support; Meridian Bioscience Inc. (Individual(s) Involved: Self): Research Grant or Support; Micromyx (Individual(s) Involved: Self): Research Grant or Support; MicuRx (Individual(s) Involved: Self): Research Grant or Support; N8 Medical (Individual(s) Involved: Self): Research Grant or Support; Nabriva (Individual(s) Involved: Self): Research Grant or Support; National Institutes of Health (Individual(s) Involved: Self): Research Grant or Support; National University of Singapore (Individual(s) Involved: Self): Research Grant or Support; North Bristol NHS Trust (Individual(s) Involved: Self): Research Grant or Support; Novome Biotechnologies (Individual(s) Involved: Self): Research Grant or Support; Paratek (Individual(s) Involved: Self): Research Grant or Support; Pfizer (Individual(s) Involved: Self): Research Grant or Support; Prokaryotics Inc. (Individual(s) Involved: Self): Research Grant or Support; QPEX Biopharma (Individual(s) Involved: Self): Research Grant or Support; Rhode Island Hospital (Individual(s) Involved: Self): Research Grant or Support; RIHML (Individual(s) Involved: Self): Research Grant or Support; Roche (Individual(s) Involved: Self): Research Grant or Support; Roivant (Individual(s) Involved: Self): Research Grant or Support; Salvat (Individual(s) Involved: Self): Research Grant or Support; Scynexis (Individual(s) Involved: Self): Research Grant or Support; SeLux Diagnostics (Individual(s) Involved: Self): Research Grant or Support; Shionogi (Individual(s) Involved: Self): Research Grant or Support; Specific Diagnostics (Individual(s) Involved: Self): Research Grant or Support; Spero (Individual(s) Involved: Self): Research Grant or Support; SuperTrans Medical LT (Individual(s) Involved: Self): Research Grant or Support; T2 Biosystems (Individual(s) Involved: Self): Research Grant or Support; The University of Queensland (Individual(s) Involved: Self): Research Grant or Support; Thermo Fisher Scientific (Individual(s) Involved: Self): Research Grant or Support; Tufts Medical Center (Individual(s) Involved: Self): Research Grant or Support; Universite de Sherbrooke (Individual(s) Involved: Self): Research Grant or Support; University of Iowa (Individual(s) Involved: Self): Research Grant or Support; University of Iowa Hospitals and Clinics (Individual(s) Involved: Self): Research Grant or Support; University of Wisconsin (Individual(s) Involved: Self): Research Grant or Support; UNT System College of Pharmacy (Individual(s) Involved: Self): Research Grant or Support; URMC (Individual(s) Involved: Self): Research Grant or Support; UT Southwestern (Individual(s) Involved: Self): Research Grant or Support; VenatoRx (Individual(s) Involved: Self): Research Grant or Support; Viosera Therapeutics (Individual(s) Involved: Self): Research Grant or Support; Wayne State University (Individual(s) Involved: Self): Research Grant or Support

1280. Minocycline Activity Against Acinetobacter baumannii-calcoaceticus Species Complex, Burkholderia Cepacia Complex, and Stenotrophomonas maltophilia from US Hospitals

Background

Acinetobacter baumannii-calcoaceticus species complex (ACB), Burkholderia cepacia complex (BCC), and Stenotrophomonas maltophilia (SM) are opportunistic non-fermentative organisms that can cause serious hospital-acquired infections in immunocompromised patients. These pathogens are inherently resistant to several common drug classes and often acquire other resistance mechanisms, making them difficult to treat. In this study, we analyzed the susceptibility of contemporary ACB, BCC, and SM isolates to minocycline (MIN), ceftazidime (TAZ), levofloxacin (LEV), and trimethoprim-sulfamethoxazole (T/S). Isolates were collected as a part of the SENTRY Antimicrobial Surveillance Program from 2017-2020.

Methods

Isolates were collected from hospitalized patients in 33 US medical centers. Hospitals submitted 1 isolate per patient per infection episode that met local criteria for being the likely causative pathogen. Identification was performed by the submitting laboratory and confirmed by JMI Laboratories with matrix-assisted laser desorption ionization-time of flight mass spectrometry or other standard methods as required. Isolates were tested for susceptibility (S) to MIN and comparators using the CLSI broth microdilution method. All infection types were included in the analysis. CLSI (2021) breakpoints were applied.

Results

The most common infection that ACB, BCC, and SM were isolated from was pneumonia in hospitalized patients (57.9%, 81.1%, and 73.9%, respectively) followed by skin and skin structure infections for ACB (21.5%) or bloodstream infections for BCC (13.5%) and SM (11.8%). The %S and MIC50/90 values of the 4 drugs tested against the organisms in this study are shown in the table. MIN had the highest %S for ACB (85.9%S) and SM (99.3%S). TAZ had the highest %S (87.8%S) for BCC, while MIN and T/S had similar %S at 82.4%S and 83.8%S, respectively.

Conclusion

MIN had &gt;82% S for the pathogens in this study, which have limited therapeutic alternatives. Options are particularly limited for BCC and SM, which have only 7 drugs with CLSI breakpoints. These in vitro data suggest that MIN remains a useful treatment option for infections caused by ACB, BCC, or SM.

Disclosures

Dee Shortridge, PhD, AbbVie (formerly Allergan) (Research Grant or Support)Melinta Therapeutics, Inc. (Research Grant or Support)Melinta Therapeutics, LLC (Research Grant or Support)Shionogi (Research Grant or Support) S J Ryan Arends, PhD, AbbVie (formerly Allergan) (Research Grant or Support)GlaxoSmithKline, LLC (Research Grant or Support)Melinta Therapeutics, LLC (Research Grant or Support)Nabriva Therapeutics (Research Grant or Support)Spero Therapeutics (Research Grant or Support) Jennifer M. Streit, BS, GlaxoSmithKline, LLC (Research Grant or Support)Melinta Therapeutics, LLC (Research Grant or Support)Shionogi (Research Grant or Support)Spero Therapeutics (Research Grant or Support) Mariana Castanheira, PhD, AbbVie (formerly Allergan) (Research Grant or Support)Bravos Biosciences (Research Grant or Support)Cidara Therapeutics, Inc. (Research Grant or Support)Cipla Therapeutics (Research Grant or Support)Cipla USA Inc. (Research Grant or Support)GlaxoSmithKline (Research Grant or Support)Melinta Therapeutics, Inc. (Research Grant or Support)Melinta Therapeutics, LLC (Research Grant or Support)Pfizer, Inc. (Research Grant or Support)Qpex Biopharma (Research Grant or Support)Shionogi (Research Grant or Support)Spero Therapeutics (Research Grant or Support) Mariana Castanheira, PhD, Affinity Biosensors (Individual(s) Involved: Self): Research Grant or Support; Allergan (Individual(s) Involved: Self): Research Grant or Support; Amicrobe, Inc (Individual(s) Involved: Self): Research Grant or Support; Amplyx Pharma (Individual(s) Involved: Self): Research Grant or Support; Artugen Therapeutics USA, Inc. (Individual(s) Involved: Self): Research Grant or Support; Astellas (Individual(s) Involved: Self): Research Grant or Support; Basilea (Individual(s) Involved: Self): Research Grant or Support; Beth Israel Deaconess Medical Center (Individual(s) Involved: Self): Research Grant or Support; BIDMC (Individual(s) Involved: Self): Research Grant or Support; bioMerieux Inc. (Individual(s) Involved: Self): Research Grant or Support; BioVersys Ag (Individual(s) Involved: Self): Research Grant or Support; Bugworks (Individual(s) Involved: Self): Research Grant or Support; Cidara (Individual(s) Involved: Self): Research Grant or Support; Cipla (Individual(s) Involved: Self): Research Grant or Support; Contrafect (Individual(s) Involved: Self): Research Grant or Support; Cormedix (Individual(s) Involved: Self): Research Grant or Support; Crestone, Inc. (Individual(s) Involved: Self): Research Grant or Support; Curza (Individual(s) Involved: Self): Research Grant or Support; CXC7 (Individual(s) Involved: Self): Research Grant or Support; Entasis (Individual(s) Involved: Self): Research Grant or Support; Fedora Pharmaceutical (Individual(s) Involved: Self): Research Grant or Support; Fimbrion Therapeutics (Individual(s) Involved: Self): Research Grant or Support; Fox Chase (Individual(s) Involved: Self): Research Grant or Support; GlaxoSmithKline (Individual(s) Involved: Self): Research Grant or Support; Guardian Therapeutics (Individual(s) Involved: Self): Research Grant or Support; Hardy Diagnostics (Individual(s) Involved: Self): Research Grant or Support; IHMA (Individual(s) Involved: Self): Research Grant or Support; Janssen Research & Development (Individual(s) Involved: Self): Research Grant or Support; Johnson & Johnson (Individual(s) Involved: Self): Research Grant or Support; Kaleido Biosceinces (Individual(s) Involved: Self): Research Grant or Support; KBP Biosciences (Individual(s) Involved: Self): Research Grant or Support; Luminex (Individual(s) Involved: Self): Research Grant or Support; Matrivax (Individual(s) Involved: Self): Research Grant or Support; Mayo Clinic (Individual(s) Involved: Self): Research Grant or Support; Medpace (Individual(s) Involved: Self): Research Grant or Support; Meiji Seika Pharma Co., Ltd. (Individual(s) Involved: Self): Research Grant or Support; Melinta (Individual(s) Involved: Self): Research Grant or Support; Menarini (Individual(s) Involved: Self): Research Grant or Support; Merck (Individual(s) Involved: Self): Research Grant or Support; Meridian Bioscience Inc. (Individual(s) Involved: Self): Research Grant or Support; Micromyx (Individual(s) Involved: Self): Research Grant or Support; MicuRx (Individual(s) Involved: Self): Research Grant or Support; N8 Medical (Individual(s) Involved: Self): Research Grant or Support; Nabriva (Individual(s) Involved: Self): Research Grant or Support; National Institutes of Health (Individual(s) Involved: Self): Research Grant or Support; National University of Singapore (Individual(s) Involved: Self): Research Grant or Support; North Bristol NHS Trust (Individual(s) Involved: Self): Research Grant or Support; Novome Biotechnologies (Individual(s) Involved: Self): Research Grant or Support; Paratek (Individual(s) Involved: Self): Research Grant or Support; Pfizer (Individual(s) Involved: Self): Research Grant or Support; Prokaryotics Inc. (Individual(s) Involved: Self): Research Grant or Support; QPEX Biopharma (Individual(s) Involved: Self): Research Grant or Support; Rhode Island Hospital (Individual(s) Involved: Self): Research Grant or Support; RIHML (Individual(s) Involved: Self): Research Grant or Support; Roche (Individual(s) Involved: Self): Research Grant or Support; Roivant (Individual(s) Involved: Self): Research Grant or Support; Salvat (Individual(s) Involved: Self): Research Grant or Support; Scynexis (Individual(s) Involved: Self): Research Grant or Support; SeLux Diagnostics (Individual(s) Involved: Self): Research Grant or Support; Shionogi (Individual(s) Involved: Self): Research Grant or Support; Specific Diagnostics (Individual(s) Involved: Self): Research Grant or Support; Spero (Individual(s) Involved: Self): Research Grant or Support; SuperTrans Medical LT (Individual(s) Involved: Self): Research Grant or Support; T2 Biosystems (Individual(s) Involved: Self): Research Grant or Support; The University of Queensland (Individual(s) Involved: Self): Research Grant or Support; Thermo Fisher Scientific (Individual(s) Involved: Self): Research Grant or Support; Tufts Medical Center (Individual(s) Involved: Self): Research Grant or Support; Universite de Sherbrooke (Individual(s) Involved: Self): Research Grant or Support; University of Iowa (Individual(s) Involved: Self): Research Grant or Support; University of Iowa Hospitals and Clinics (Individual(s) Involved: Self): Research Grant or Support; University of Wisconsin (Individual(s) Involved: Self): Research Grant or Support; UNT System College of Pharmacy (Individual(s) Involved: Self): Research Grant or Support; URMC (Individual(s) Involved: Self): Research Grant or Support; UT Southwestern (Individual(s) Involved: Self): Research Grant or Support; VenatoRx (Individual(s) Involved: Self): Research Grant or Support; Viosera Therapeutics (Individual(s) Involved: Self): Research Grant or Support; Wayne State University (Individual(s) Involved: Self): Research Grant or Support

Frequency of occurrence and antimicrobial susceptibility of bacteria isolated from respiratory samples of patients hospitalized with pneumonia in Western Europe, Eastern Europe and the USA: results from the SENTRY Antimicrobial Surveillance Program (2016-19)

Background

The SENTRY Antimicrobial Surveillance Program monitors the frequency of occurrence and antimicrobial susceptibility of organisms from various infection types worldwide.

Objectives

To evaluate the SENTRY programme results for organisms isolated from respiratory samples of patients hospitalized with probable pneumonia.

Methods

A total of 28 918 bacterial isolates were consecutively collected (one per patient) in 2016-19 from 121 medical centres located in western Europe (W-EU; n = 7966), eastern Europe (E-EU; n = 3182) and the USA (n = 17 770) and then susceptibility tested by reference broth microdilution methods in a central laboratory.

Results

Gram-negative bacilli (GNB) represented 76.3%, 88.6% and 69.1% of organisms; non-fermentative (NF) GNB accounted for 26.9%, 51.8% and 34.6% of organisms in W-EU, E-EU and USA, respectively. Pseudomonas aeruginosa susceptibility to piperacillin/tazobactam and meropenem was 75.4% and 76.9% in W-EU, 57.4% and 48.3% in E-EU, and 76.1% and 74.8% in the USA, respectively. Only 10.4% of Acinetobacter baumannii isolates from E-EU were meropenem susceptible compared with 45.8% in W-EU and 58.8% in the USA. Overall MRSA rates were 21.4% in W-EU and 28.7% in E-EU. In the USA, MRSA rates decreased from 44.8% in 2016 to 40.1% in 2019. Carbapenem resistance among Enterobacterales decreased continuously in the USA from 3.0% in 2016 to 1.7% in 2019 (2.4% overall) and was higher in E-EU (16.6%) than W-EU (2.2%). Klebsiella pneumoniae susceptibility to meropenem was 91.3%, 72.5% and 95.3% in W-EU, E-EU and the USA, respectively.

Conclusions

Rank order and antimicrobial susceptibility of bacteria isolated from patients with pneumonia widely varied by geography. MDR NF-GNB represented an important cause of pneumonia.

Antimicrobial susceptibility of Gram-negative bacteria from intensive care unit and non-intensive care unit patients from United States hospitals (2018-2020)

We evaluated the antimicrobial susceptibility of Gram-negative bacteria recovered from ICU patients in US hospitals and compared them to those from non-ICU patients from the same hospitals during the same period. Overall, 4,680 isolates from ICU patients and 16,263 isolates from non-ICU patients were collected from 70 US medical centers in 2018-2020 and susceptibility tested by the broth microdilution method. Ceftazidime-avibactam and ceftolozane-tazobactam were the most active agents against P. aeruginosa and retained activity against multidrug-resistant (MDR) and extensively drug-resistant (XDR) isolates. Minocycline and trimethoprim-sulfamethoxazole were very active against S. maltophilia, whereas most antimicrobial agents exhibited low susceptibility to A. baumannii. Ceftazidime-avibactam and meropenem-vaborbactam were the most active agents against Enterobacterales, and retained potent activity against ESBL producers, carbapenem-resistant Enterobacterales (CRE), MDR, and XDR isolates. In summary, antimicrobial susceptibility was generally lower and the occurrence of ESBL, CRE, MDR, and XDR phenotypes were clearly higher among ICU compared to non-ICU isolates.

Minocycline Activity against Unusual Clinically Significant Gram-Negative Pathogens

The minocycline susceptibility of 3,856 isolates including Burkholderia, Achromobacter, Alcaligenes, Aeromonas, and Stenotrophomonas maltophilia from the SENTRY surveillance (2014 to 2019) were analyzed. The susceptibilities of these species (%S) were Achromobacter spp. (n = 411; 92.6%), Burkholderia cepacia species complex (n = 199; 85.9%), Aeromonas spp. (n = 127; 99.2%), Chryseobacterium spp. (n = 59; 94.9%), Alcaligenes faecalis (n = 42; 88.1%), and S. maltophilia (n = 2,287; 99.5%). These data suggest that minocycline is a useful treatment option for infections caused by unusual Gram-negative pathogens.

Investigation of mechanisms responsible for decreased susceptibility of aztreonam/avibactam activity in clinical isolates of Enterobacterales collected in Europe, Asia and Latin America in 2019

Background

The combination aztreonam/avibactam is currently under Phase 3 trials for the treatment of serious infections caused by Gram-negative bacteria including those with MBLs.

Objectives

To investigate the resistance mechanisms in Enterobacterales exhibiting aztreonam/avibactam MICs of ≥4 mg/L.

Methods

Among 8787 Enterobacterales, 17 (0.2%) isolates exhibited an aztreonam/avibactam MIC of ≥4 mg/L. Isolates were sequenced and screened for β-lactamases. Sequences of porins, penicillin-binding protein 3 (PBP3) and expression levels of AmpC and AcrA were evaluated.

Results

Eleven (11/4154 isolates; 0.26%) Escherichia coli, three (3/1981; 0.15%) Klebsiella pneumoniae and three (3/628; 0.5%) Enterobacter cloacae were identified. All E. coli showed either an ‘YRIK’ or ‘YRIN’ insertion in PBP3. In general, these isolates carried bla_CMY and/or bla_CTX-M variants, except for one isolate from Korea that also produced NDM-5 and one isolate from Turkey that produced OXA-48. Two DHA-1-producing K. pneumoniae overexpressed acrA and had a premature stop codon in either OmpK35 or OmpK36, whereas a third K. pneumoniae carried bla_PER-2 and had a premature stop codon in OmpK35. All three E. cloacae expressed AmpC at levels ≥570-fold, but sequence analysis did not reveal known amino acid alterations associated with decreased avibactam binding or increased hydrolysis of β-lactams. Minor amino acid polymorphisms within OmpC, OmpF and PBP3 were noted among the E. cloacae.

Conclusions

A small number of isolates (0.2%) met the inclusion criteria. E. coli showed altered PBP3 as the most relevant resistance mechanism, whereas K. pneumoniae had multiple resistance mechanisms. Further investigations are needed to clarify resistance in E. cloacae.

1590. Activity of Meropenem-Vaborbactam and Single-Agent Comparators against Enterobacterales Isolates Including KPC-Producing Isolates, from European Patients Hospitalized with Pneumonia Including Ventilator-Associated Pneumonia (2014-2019)

Background

Meropenem-vaborbactam (MVB) was recently approved in Europe for the treatment of complicated UTIs, including acute pyelonephritis, complicated intra-abdominal infections, hospital-acquired bacterial pneumonia, ventilator-associated pneumonia (VAP), and bacteremia. KPC-producing Enterobacterales (ENT) isolates have disseminated worldwide. We analysed the activity of MVB and single-agent comparators against 6,846 ENT isolates from patients hospitalised with pneumonia (PHP) including VAP in European hospitals (2014–2019).

Methods

Among 6,846 ENT clinical isolates from PHP collected in 40 European hospitals located in 20 countries that were susceptibility (S) tested using reference broth microdilution methods. Of the carbapenem-resistant isolates submitted to whole genome sequencing, 75 carried bla_KPC. ENT isolates were also characterized for an extended spectrum beta-lactamase (ESBL) phenotype as described (CLSI, 2020). EUCAST (2020) interpretive criteria were used. %S from patients in the intensive care unit (ICU), ICU patients with VAP, and non-ICU isolates were also analysed.

Results

The most common ENT pathogens isolated from PHP were Klebsiella pneumoniae (KPN; n=1,877) and Escherichia coli (EC; n=1,646). The %S of MVB and comparators to ENT, ICU, ICU/VAP, and non-ICU are shown in the table. Overall, 98.2% of ENT were S to MVB. For 3,218 ENT isolates from ICU patients, MVB %S was 96.6% and for 2,627 non-ICU isolates MVB %S was 98.5%. The %S of comparators for ICU vs non-ICU isolates were similar, except for levofloxacin. 29 KPC-producing isolates were from ICU (11 from VAP), 46 were from non-ICU. Most KPC-producing isolates were KPN (n=71; 54 bla_KPC-3, 16 bla_KPC-2 and 1 bla_KPC-12). 4 EC contained bla_KPC-3. KPC were from 7 countries, Italy had the highest number of KPC-producing isolates at 42 (56%). MVB inhibited 100% of KPC-producing isolates. Amikacin was the most active comparator against all ENT (94.2%S); colistin was the most active comparator against KPC-producing isolates (79.7%S).

Conclusion

These results demonstrate MVB has potent activity against ENT isolates from PHP including those producing KPC enzymes and suggest MVB is a useful treatment option for ICU and non-ICU PHP including VAP.

Table 1

Disclosures

Leonard R. Duncan, PhD, A. Menarini Industrie Farmaceutiche Riunite S.R.L. (Research Grant or Support)Basilea Pharmaceutica International, Ltd. (Research Grant or Support)Dept of Health and Human Services (Research Grant or Support) Jennifer M. Streit, BS, A. Menarini Industrie Farmaceutiche Riunite S.R.L. (Research Grant or Support)A. Menarini Industrie Farmaceutiche Riunite S.R.L. (Research Grant or Support)Allergan (Research Grant or Support)Melinta Therapeutics, Inc. (Research Grant or Support)Melinta Therapeutics, Inc. (Research Grant or Support)Melinta Therapeutics, Inc. (Research Grant or Support)Merck (Research Grant or Support)Paratek Pharma, LLC (Research Grant or Support) Mariana Castanheira, PhD, 1928 Diagnostics (Research Grant or Support)A. Menarini Industrie Farmaceutiche Riunite S.R.L. (Research Grant or Support)Allergan (Research Grant or Support)Allergan (Research Grant or Support)Amplyx Pharmaceuticals (Research Grant or Support)Cidara Therapeutics (Research Grant or Support)Cidara Therapeutics (Research Grant or Support)Cipla Ltd. (Research Grant or Support)Cipla Ltd. (Research Grant or Support)Fox Chase Chemical Diversity Center (Research Grant or Support)GlaxoSmithKline (Research Grant or Support)Melinta Therapeutics, Inc. (Research Grant or Support)Melinta Therapeutics, Inc. (Research Grant or Support)Melinta Therapeutics, Inc. (Research Grant or Support)Merck (Research Grant or Support)Merck (Research Grant or Support)Merck & Co, Inc. (Research Grant or Support)Merck & Co, Inc. (Research Grant or Support)Paratek Pharma, LLC (Research Grant or Support)Pfizer (Research Grant or Support)Qpex Biopharma (Research Grant or Support)

327. Oritavancin Activity against Staphylococcus aureus Isolates Causing Bone and Joint Infections in European Hospitals (2010–2019)

Background

Bone and joint infections (BJI) frequently are caused by Staphylococcus aureus (SA), and since prolonged therapy courses typically are required, agents with convenient administration are preferred. Oritavancin (ORI) is a long-acting lipoglycopeptide approved as a single dose regimen for treating skin and skin structure infections. This study evaluates the activity of ORI and comparators against SA causing BJI in European (EU) hospitals.

Methods

A total of 575 SA isolates from the SENTRY Antimicrobial Surveillance Program causing BJI in 15 EU countries from 2010 to 2019 were included. Bacterial identification was confirmed by MALDI-TOF MS. Broth microdilution susceptibility (S) testing and interpretation was performed following current CLSI guidelines. The activities of ORI and comparators were evaluated across the years and by EU region: western Europe (W-EU; 491 isolates) and eastern EU/Mediterranean region (E-EU; 84 isolates).

Results

Methicillin resistance (MRSA) was observed in 20.5% of SA (18.5% in W-EU and 32.1% in E-EU), ranging from 31.1% in 2011 to 14.6% in 2016. MRSA rates were slightly lower in 2016–2019 (14.6%-19.2%) than previous years (2011–2013; 24.4%-31.1%). ORI exhibited 100.0% susceptibility across the entire SA collection with yearly MIC₅₀ and MIC₉₀ variations within 1 doubling dilutions (MIC₅₀ and MIC₉₀, 0.015–0.03 and 0.03–0.06 mg/L, respectively), regardless the MRSA phenotype or EU region. Daptomycin, vancomycin, teicoplanin, and linezolid also showed complete coverage against SA. Clindamycin (CLI; >99.0%S) and levofloxacin (> 95.0%S) were active against methicillin-susceptible SA, but less active against MRSA (67.8%S and 16.1%S, respectively). E-EU MRSA isolates displayed lower S rates than W-EU MRSA isolates to ceftaroline (83.3% vs. 90.6%), CLI (44.4% vs. 74.7%) and tetracycline (66.7% vs. 89.0%), respectively.

Conclusion

MRSA rates among isolates causing BJI varied within regions. Although several drugs were in vitro active against MSSA, options remained limited against MRSA. ORI showed in vitro activity against the entire collection of European SA isolates and may be a consideration for treating BJI with the convenience of drug administration.

Table 1

Disclosures

Cecilia G. Carvalhaes, MD, PhD, A. Menarini Industrie Farmaceutiche Riunite S.R.L. (Research Grant or Support)Allergan (Research Grant or Support)Cidara Therapeutics (Research Grant or Support)Cipla Ltd. (Research Grant or Support)Fox Chase Chemical Diversity Center (Research Grant or Support)Melinta Therapeutics, Inc. (Research Grant or Support)Merck (Research Grant or Support)Merck (Research Grant or Support)Merck & Co, Inc. (Research Grant or Support)Pfizer (Research Grant or Support) Jennifer M. Streit, BS, A. Menarini Industrie Farmaceutiche Riunite S.R.L. (Research Grant or Support)A. Menarini Industrie Farmaceutiche Riunite S.R.L. (Research Grant or Support)Allergan (Research Grant or Support)Melinta Therapeutics, Inc. (Research Grant or Support)Melinta Therapeutics, Inc. (Research Grant or Support)Melinta Therapeutics, Inc. (Research Grant or Support)Merck (Research Grant or Support)Paratek Pharma, LLC (Research Grant or Support) Helio S. Sader, MD, PhD, A. Menarini Industrie Farmaceutiche Riunite S.R.L. (Research Grant or Support)Allergan (Research Grant or Support)Allergan (Research Grant or Support)Allergan (Research Grant or Support)Cipla Ltd. (Research Grant or Support)Cipla Ltd. (Research Grant or Support)Melinta (Research Grant or Support)Merck (Research Grant or Support)Merck (Research Grant or Support)Paratek Pharma, LLC (Research Grant or Support)Pfizer (Research Grant or Support) Rodrigo E. Mendes, PhD, A. Menarini Industrie Farmaceutiche Riunite S.R.L. (Research Grant or Support)Allergan (Research Grant or Support)Allergan (Research Grant or Support)Basilea Pharmaceutica International, Ltd (Research Grant or Support)Cipla Ltd. (Research Grant or Support)Department of Health and Human Services (Research Grant or Support)GlaxoSmithKline (Research Grant or Support)Melinta Therapeutics, Inc. (Research Grant or Support)Merck (Research Grant or Support)Merck (Research Grant or Support)Pfizer (Research Grant or Support)

1472. Frequency of Occurrence and Antimicrobial Susceptibility of Bacteria Isolated from Patients Hospitalized with Bacterial Pneumonia in the United States, Western Europe, and Eastern Europe: Results from the SENTRY Program (2016-2019)

Background

The SENTRY Antimicrobial Surveillance Program monitors the frequency of occurrence and antimicrobial susceptibility of organisms from various infection types worldwide. In this investigation, we evaluate the results for organisms isolated from patients hospitalized with bacterial pneumonia.

Methods

28,918 bacterial isolates were consecutively collected (1/patient) in 2016-2019 from 121 medical centers located in the United States (US; n=17,770; 82 centers), western Europe (W-EU; n=7,966; 25 centers from 10 nations), and eastern Europe (E-EU; n=3,182; 14 centers from 11 nations). Organisms were tested for susceptibility by reference broth microdilution methods in a central laboratory.

Results

The rank order of organisms varied markedly among geographic regions (Table). Gram-negative bacilli (GNB) represented 69.1%, 76.3%, and 88.6% of organisms; and non-fermentative (NF) GNB represented 34.6%, 26.9%, and 51.8% of organisms in US, W-EU, and E-EU, respectively. Among NF-GNB, P. aeruginosa ranked first in W-EU and E-EU and second in the US, A. baumannii ranked third in E-EU, and S. maltophilia was among the top 8 in all 3 regions (fifth in the US). P. aeruginosa susceptibility to piperacillin-tazobactam and meropenem (MEM) were 76.1% and 74.8% in the US, 75.4% and 76.9% in W-EU, and 57.4% and 48.3% in E-EU, respectively. Only 10.4% of A. baumannii isolates from E-EU were MEM-susceptible compared to 45.8% in W-EU and 58.7% in the US. MRSA rates in the US improved from 44.8% in 2016 to 40.2% in 2019 (p< 0.05). Overall MRSA rates were 21.4% in W-EU, and 28.7% in E-EU. CRE rates decreased continuously in the US from 3.0% in 2016 to 1.7% in 2019 (p < 0.05; 2.4% overall) and were higher E=EU (16.6%) than W-EU (2.2%). Among K. pneumoniae, susceptibility to ceftriaxone and MEM were 80.7% and 94.9% in the US, 70.1% and 90.7% in W-EU, and 34.5% and 70.4% in E-EU, respectively. Among E. coli, susceptibility to ceftriaxone and levofloxacin were 71.4% and 55.0% in the US, 79.2% and 71.2% in W-EU, and 62.6% and 55.9% in E-EU, respectively.

Table 1

Conclusion

Rank order and antimicrobial susceptibility of bacteria isolated from patients with pneumonia varied widely by geographic region. Multidrug-resistant NF-GNB represented an important cause of pneumonia in US and Europe.

Disclosures

Helio S. Sader, MD, PhD, A. Menarini Industrie Farmaceutiche Riunite S.R.L. (Research Grant or Support)Allergan (Research Grant or Support)Allergan (Research Grant or Support)Allergan (Research Grant or Support)Cipla Ltd. (Research Grant or Support)Cipla Ltd. (Research Grant or Support)Melinta (Research Grant or Support)Merck (Research Grant or Support)Merck (Research Grant or Support)Paratek Pharma, LLC (Research Grant or Support)Pfizer (Research Grant or Support) Cecilia G. Carvalhaes, MD, PhD, A. Menarini Industrie Farmaceutiche Riunite S.R.L. (Research Grant or Support)Allergan (Research Grant or Support)Cidara Therapeutics (Research Grant or Support)Cipla Ltd. (Research Grant or Support)Fox Chase Chemical Diversity Center (Research Grant or Support)Melinta Therapeutics, Inc. (Research Grant or Support)Merck (Research Grant or Support)Merck (Research Grant or Support)Merck & Co, Inc. (Research Grant or Support)Pfizer (Research Grant or Support) Jennifer M. Streit, BS, A. Menarini Industrie Farmaceutiche Riunite S.R.L. (Research Grant or Support)A. Menarini Industrie Farmaceutiche Riunite S.R.L. (Research Grant or Support)Allergan (Research Grant or Support)Melinta Therapeutics, Inc. (Research Grant or Support)Melinta Therapeutics, Inc. (Research Grant or Support)Melinta Therapeutics, Inc. (Research Grant or Support)Merck (Research Grant or Support)Paratek Pharma, LLC (Research Grant or Support) Rodrigo E. Mendes, PhD, A. Menarini Industrie Farmaceutiche Riunite S.R.L. (Research Grant or Support)Allergan (Research Grant or Support)Allergan (Research Grant or Support)Basilea Pharmaceutica International, Ltd (Research Grant or Support)Cipla Ltd. (Research Grant or Support)Department of Health and Human Services (Research Grant or Support)GlaxoSmithKline (Research Grant or Support)Melinta Therapeutics, Inc. (Research Grant or Support)Merck (Research Grant or Support)Merck (Research Grant or Support)Pfizer (Research Grant or Support) Mariana Castanheira, PhD, 1928 Diagnostics (Research Grant or Support)A. Menarini Industrie Farmaceutiche Riunite S.R.L. (Research Grant or Support)Allergan (Research Grant or Support)Allergan (Research Grant or Support)Amplyx Pharmaceuticals (Research Grant or Support)Cidara Therapeutics (Research Grant or Support)Cidara Therapeutics (Research Grant or Support)Cipla Ltd. (Research Grant or Support)Cipla Ltd. (Research Grant or Support)Fox Chase Chemical Diversity Center (Research Grant or Support)GlaxoSmithKline (Research Grant or Support)Melinta Therapeutics, Inc. (Research Grant or Support)Melinta Therapeutics, Inc. (Research Grant or Support)Melinta Therapeutics, Inc. (Research Grant or Support)Merck (Research Grant or Support)Merck (Research Grant or Support)Merck & Co, Inc. (Research Grant or Support)Merck & Co, Inc. (Research Grant or Support)Paratek Pharma, LLC (Research Grant or Support)Pfizer (Research Grant or Support)Qpex Biopharma (Research Grant or Support)

1449. Frequency and Antimicrobial Susceptibility of Coagulase-Negative Staphylococcal (CoNS) Species Isolated from Clinical Specimens in United States and European Hospitals

Background

CoNS represent an important cause of bloodstream infections, osteoarticular infections, foreign-body-associated infections and endocarditis. We evaluated the frequency of CoNS species and the activity of dalbavancin (DALB) in comparison to vancomycin (VAN), daptomycin (DAP) and other agents against a large collection of CoNS isolates.

Methods

5,088 CoNS isolates causing clinically significant infection were consecutively collected from 122 medical centers located in the United States (79 centers) and Europe (43 centers in 21 nations) over 6 years (2014-2019) and susceptibility tested by CLSI broth microdilution methods against DALB and comparators. Species identification was confirmed by MALDI-TOF.

Results

Most isolates were from bloodstream (BSI; 53.5%) or skin/skin structure infections (28.5%). S. epidermidis was the most common species overall (54.6%; Table) and for BSI (61.3%). The second most common species were S. lugdunensis overall (12.3%) and S. hominis for BSI (14.7%). DALB (MIC50/90, 0.03/0.06 mg/L) inhibited &gt; 99.9% of CoNS isolates at the susceptible (S) breakpoint established by CLSI for S. aureus (≤ 0.25 mg/L) and was 8-fold more active than DAP (MIC50/90, 0.25/0.5 mg/L; 99.9% S) and 32-fold more active than VAN (MIC50/90, 1/2 mg/L; &gt; 99.9% S). Linezolid was active against 98.7% of isolates (MIC50/90, 0.5/1 mg/L). All species were inhibited at ≤0.25 mg/L of DALB, except S. epidermidis (&gt; 99.9%) and S. warneri (98.9%; Table). The most DALB-S species were S. capitis and S. simulans (MIC50/90, 0.015/0.03 mg/L for both species), whereas the highest DALB MIC50/90 values were observed with S. haemolyticus and S. saprophyticus (MIC50/90, 0.06/0.12 mg/L and highest MIC of 0.25 mg/L for both species). In contrast, 47.8% of S. epidermidis and 34.7% S. haemolyticus exhibited decreased susceptibility to VAN (MIC ≥ 2 mg/L), and 23.2% of S. capitis and 28.4% of S. warneri showed decreased susceptibility to DAP (MIC ≥ 1 mg/L). Overall oxacillin-S rate was 39.3%, varying from 3.0% for S. saprophyticus to 95.4% for S. lugdunensis. In general, BSI isolates were slightly less S than non-BSI isolates.

Conclusion

Antimicrobial susceptibility varied widely among CoNS species. DALB exhibited potent in vitro activity against all CoNS species.

Table 1

Disclosures

Helio S. Sader, MD, PhD, A. Menarini Industrie Farmaceutiche Riunite S.R.L. (Research Grant or Support)Allergan (Research Grant or Support)Allergan (Research Grant or Support)Allergan (Research Grant or Support)Cipla Ltd. (Research Grant or Support)Cipla Ltd. (Research Grant or Support)Melinta (Research Grant or Support)Merck (Research Grant or Support)Merck (Research Grant or Support)Paratek Pharma, LLC (Research Grant or Support)Pfizer (Research Grant or Support) Cecilia G. Carvalhaes, MD, PhD, A. Menarini Industrie Farmaceutiche Riunite S.R.L. (Research Grant or Support)Allergan (Research Grant or Support)Cidara Therapeutics (Research Grant or Support)Cipla Ltd. (Research Grant or Support)Fox Chase Chemical Diversity Center (Research Grant or Support)Melinta Therapeutics, Inc. (Research Grant or Support)Merck (Research Grant or Support)Merck (Research Grant or Support)Merck & Co, Inc. (Research Grant or Support)Pfizer (Research Grant or Support) Jennifer M. Streit, BS, A. Menarini Industrie Farmaceutiche Riunite S.R.L. (Research Grant or Support)A. Menarini Industrie Farmaceutiche Riunite S.R.L. (Research Grant or Support)Allergan (Research Grant or Support)Melinta Therapeutics, Inc. (Research Grant or Support)Melinta Therapeutics, Inc. (Research Grant or Support)Melinta Therapeutics, Inc. (Research Grant or Support)Merck (Research Grant or Support)Paratek Pharma, LLC (Research Grant or Support) S. J. Ryan Arends, PhD, Allergan (Research Grant or Support)Cipla Ltd. (Research Grant or Support)GlaxoSmithKline (Research Grant or Support)Melinta Therapeutics, Inc. (Research Grant or Support) Rodrigo E. Mendes, PhD, A. Menarini Industrie Farmaceutiche Riunite S.R.L. (Research Grant or Support)Allergan (Research Grant or Support)Allergan (Research Grant or Support)Basilea Pharmaceutica International, Ltd (Research Grant or Support)Cipla Ltd. (Research Grant or Support)Department of Health and Human Services (Research Grant or Support)GlaxoSmithKline (Research Grant or Support)Melinta Therapeutics, Inc. (Research Grant or Support)Merck (Research Grant or Support)Merck (Research Grant or Support)Pfizer (Research Grant or Support)

1589. Activity of Meropenem-Vaborbactam and Comparators against Globally Disseminated Klebsiella pneumoniae Sequence Type 258

Background

Meropenem-vaborbactam (MVB) is a combination of a carbapenem and a b-lactamase inhibitor active against β-lactamases including serine carbapenemases. MVB recently was approved in the US and Europe for the treatment of complicated UTIs, including acute pyelonephritis, and is approved in Europe for treatment of complicated intra-abdominal infections, hospital-acquired bacterial pneumonia, ventilator-associated pneumonia, and bacteremia. Carbapenemase-producing Enterobacterales (ENT) isolates, particularly Klebsiella pneumoniae (KPN), have disseminated worldwide and are considered endemic in various countries. Carbapenem-resistant (CR) KPN outbreaks have been associated with KPN sequence-type 258 (ST258). Globally, 60-70% of KPC-producing KPN belong to ST258. In this study, we examined the susceptibilities of ST258 isolates collected as a part of the SENTRY global surveillance program.

Methods

KPN isolates from 2016-2019 were susceptibility tested by reference broth microdilution methods. The results were interpreted using CLSI 2020 breakpoints. The sequence type and presence of carbapenemases were determined by whole genome sequencing and analysis.

Results

130 KPN ST258 isolates were identified in 6 countries. All isolates were extremely drug resistant (XDR, susceptible to < = 1 agent in 2 or fewer drug classes). 76.2% were CR, and 71 isolates contained bla_KPC-2, 25 bla_KPC-3 and 1 bla_KPC-12. One isolate contained bla_NDM-1. The US had the most ST258 isolates (n=56), of which 22 produced KPC-2 and 19 produced KPC-3. Greece had 32 isolates, with 17 KPC-2 and 5 KPC-3. Brazil had 22 isolates, 17 with KPC-2. The single NDM-1 producing isolate was from Argentina. Susceptibilities to MVB and comparators by country are shown in the table. MVB inhibited 99.2% of the isolates and was the most active agent overall, only 23.1% were meropenem susceptible. Tigecycline was the most active comparator with 98.5% susceptible.

Conclusion

These results demonstrate MVB has potent activity against the internationally disseminated KPN clone ST258 including those producing KPC. MVB may be useful for the treatment of infections caused by XDR K. pneumoniae.

Table 1

Disclosures

Timothy B. Doyle, Allergan (Research Grant or Support)Allergan (Research Grant or Support)Cipla Ltd. (Research Grant or Support)Melinta Therapeutics, Inc. (Research Grant or Support)Pfizer (Research Grant or Support)Qpex Biopharma (Research Grant or Support) Jennifer M. Streit, BS, A. Menarini Industrie Farmaceutiche Riunite S.R.L. (Research Grant or Support)A. Menarini Industrie Farmaceutiche Riunite S.R.L. (Research Grant or Support)Allergan (Research Grant or Support)Melinta Therapeutics, Inc. (Research Grant or Support)Melinta Therapeutics, Inc. (Research Grant or Support)Melinta Therapeutics, Inc. (Research Grant or Support)Merck (Research Grant or Support)Paratek Pharma, LLC (Research Grant or Support) Mariana Castanheira, PhD, 1928 Diagnostics (Research Grant or Support)A. Menarini Industrie Farmaceutiche Riunite S.R.L. (Research Grant or Support)Allergan (Research Grant or Support)Allergan (Research Grant or Support)Amplyx Pharmaceuticals (Research Grant or Support)Cidara Therapeutics (Research Grant or Support)Cidara Therapeutics (Research Grant or Support)Cipla Ltd. (Research Grant or Support)Cipla Ltd. (Research Grant or Support)Fox Chase Chemical Diversity Center (Research Grant or Support)GlaxoSmithKline (Research Grant or Support)Melinta Therapeutics, Inc. (Research Grant or Support)Melinta Therapeutics, Inc. (Research Grant or Support)Melinta Therapeutics, Inc. (Research Grant or Support)Merck (Research Grant or Support)Merck (Research Grant or Support)Merck & Co, Inc. (Research Grant or Support)Merck & Co, Inc. (Research Grant or Support)Paratek Pharma, LLC (Research Grant or Support)Pfizer (Research Grant or Support)Qpex Biopharma (Research Grant or Support)

333. Tedizolid Activity against Gram-Positive Bacterial Isolates Causing Bone and Joint Infections in the United States (2015–2019)

Background

Prolonged systemic antibiotic courses are frequently used to manage difficult-to-treat bone and joint infections (BJI). Tedizolid has been considered as a therapy candidate for BJI in adults and children. This study assessed the in vitro activity of tedizolid and comparator agents against a contemporary collection of Gram-positive (GP) isolates causing BJI in the US.

Methods

A total of 310 Staphylococcus aureus (SA), 79 β-hemolytic streptococci (BHS), 52 coagulase-negative staphylococci (CoNS), and 37 Enterococcus faecalis isolates were included in this study. These isolates were collected from patients with BJI from 30 medical centers in the US between 2015 and 2019 as a part of the Surveillance of Tedizolid Activity and Resistance (STAR) Program. Bacterial identification was confirmed by MALDI-TOF MS. MIC results were obtained by reference CLSI broth microdilution methods and interpretations used CLSI guidelines.

Results

Tedizolid (MIC_50/90, 0.12/0.25 mg/L) inhibited all SA at the CLSI breakpoint (≤0.5 mg/L) including methicillin-resistant SA (MRSA; 35.8% of SA; MIC_50/90, 0.12/0.25 mg/L). Linezolid, vancomycin, and daptomycin had 100% susceptibility rates against SA isolates (Table). All CoNS isolates were inhibited by tedizolid at ≤0.5 mg/L. Tedizolid was active against all BHS (100% susceptible) as follows: S. pyogenes (n=24; MIC_50/90, 0.12/0.25 mg/L), S. agalactiae (n=44; MIC_50/90, 0.12/0.25 mg/L), and S. dysgalactiae (n= 11; MIC_50/90, 0.25/0.25 mg/L). Penicillin, linezolid, vancomycin, and daptomycin also were active against BHS (100% susceptible). Tedizolid (MIC_50/90, 0.25/0.25 mg/L; 100% susceptible) was 4- to 8-fold more potent than linezolid (MIC_50/90, 1/1 mg/L) and vancomycin (MIC_50/90, 1/2 mg/L) against E. faecalis. GP isolates resistant to oxazolidinone were not observed.

Conclusion

Tedizolid demonstrated potent in vitro activity against this collection of contemporary GP isolates causing BJI in US hospitals. Tedizolid and comparator agents showed high susceptibility rates against the most frequent organisms and organism groups, including MRSA. These findings support the clinical development of tedizolid as an additional option for treating BJI caused by GP pathogens.

Table 1

Disclosures

Cecilia G. Carvalhaes, MD, PhD, A. Menarini Industrie Farmaceutiche Riunite S.R.L. (Research Grant or Support)Allergan (Research Grant or Support)Cidara Therapeutics (Research Grant or Support)Cipla Ltd. (Research Grant or Support)Fox Chase Chemical Diversity Center (Research Grant or Support)Melinta Therapeutics, Inc. (Research Grant or Support)Merck (Research Grant or Support)Merck (Research Grant or Support)Merck & Co, Inc. (Research Grant or Support)Pfizer (Research Grant or Support) Helio S. Sader, MD, PhD, A. Menarini Industrie Farmaceutiche Riunite S.R.L. (Research Grant or Support)Allergan (Research Grant or Support)Allergan (Research Grant or Support)Allergan (Research Grant or Support)Cipla Ltd. (Research Grant or Support)Cipla Ltd. (Research Grant or Support)Melinta (Research Grant or Support)Merck (Research Grant or Support)Merck (Research Grant or Support)Paratek Pharma, LLC (Research Grant or Support)Pfizer (Research Grant or Support) Jennifer M. Streit, BS, A. Menarini Industrie Farmaceutiche Riunite S.R.L. (Research Grant or Support)A. Menarini Industrie Farmaceutiche Riunite S.R.L. (Research Grant or Support)Allergan (Research Grant or Support)Melinta Therapeutics, Inc. (Research Grant or Support)Melinta Therapeutics, Inc. (Research Grant or Support)Melinta Therapeutics, Inc. (Research Grant or Support)Merck (Research Grant or Support)Paratek Pharma, LLC (Research Grant or Support) Mariana Castanheira, PhD, 1928 Diagnostics (Research Grant or Support)A. Menarini Industrie Farmaceutiche Riunite S.R.L. (Research Grant or Support)Allergan (Research Grant or Support)Allergan (Research Grant or Support)Amplyx Pharmaceuticals (Research Grant or Support)Cidara Therapeutics (Research Grant or Support)Cidara Therapeutics (Research Grant or Support)Cipla Ltd. (Research Grant or Support)Cipla Ltd. (Research Grant or Support)Fox Chase Chemical Diversity Center (Research Grant or Support)GlaxoSmithKline (Research Grant or Support)Melinta Therapeutics, Inc. (Research Grant or Support)Melinta Therapeutics, Inc. (Research Grant or Support)Melinta Therapeutics, Inc. (Research Grant or Support)Merck (Research Grant or Support)Merck (Research Grant or Support)Merck & Co, Inc. (Research Grant or Support)Merck & Co, Inc. (Research Grant or Support)Paratek Pharma, LLC (Research Grant or Support)Pfizer (Research Grant or Support)Qpex Biopharma (Research Grant or Support) Rodrigo E. Mendes, PhD, A. Menarini Industrie Farmaceutiche Riunite S.R.L. (Research Grant or Support)Allergan (Research Grant or Support)Allergan (Research Grant or Support)Basilea Pharmaceutica International, Ltd (Research Grant or Support)Cipla Ltd. (Research Grant or Support)Department of Health and Human Services (Research Grant or Support)GlaxoSmithKline (Research Grant or Support)Melinta Therapeutics, Inc. (Research Grant or Support)Merck (Research Grant or Support)Merck (Research Grant or Support)Pfizer (Research Grant or Support)

1620. Minocycline Activity Against Unusual Clinically Significant Gram-Negative Pathogens

Background

Unusual non-glucose fermenting Gram-negative (NFGN) pathogens, including Burkholderia cepacia species complex, Achromobacter spp, Alcaligenes spp, Aeromonas spp, and other genera, can cause serious hospital-acquired infections in immunocompromised patients. Some genera are inherently resistant to common drug classes and can acquire other resistance mechanisms, making them difficult to treat. In this study, we analyzed the susceptibility of NFGN isolates to minocycline (MIN). Isolates were collected as part of the SENTRY Antimicrobial Surveillance Program from 2014-2019.

Methods

From 2014-2019, unusual NFGN isolates were collected from hospitalized patients in 102 hospitals in 35 countries on 4 continents. Hospitals submitted 1 isolate per patient per infection episode that met local criteria for being the likely causative pathogen. Identification was performed by the submitting laboratory and confirmed by JMI Laboratories with matrix-assisted laser desorption ionization-time of flight mass spectrometry or other molecular methods as required. Isolates were tested for MIN susceptibility using the CLSI broth microdilution method at JMI Laboratories. All infection types were included in the susceptibility analysis.

Results

The most common infection from which the NFGN were isolated was pneumonia. The top 5 NFGN species were Achromobacter xylosoxidans (n=202), Burkholderia cepacia species complex (n=199), unspeciated Achromobacter (n=190), Aeromonas spp (n=127), including Aeromonas hydrophila (n=35), Chryseobacterium spp (n=59), and Alcaligenes faecalis (n=42). The % susceptible and MIC_50/90 values of MIN for these species are shown in the table.

Conclusion

MIN had > 85% susceptible for the most frequently isolated unusual NFGN, including 92% susceptible for Achromobacter spp. and 85.9% for B. cepacia. These data suggest that MIN remains a useful treatment option for infections caused by unusual NFGN.

Activities of MIN when tested against NFGN isolates

Disclosures

S. J. Ryan Arends, PhD, Allergan (Research Grant or Support)Cipla Ltd. (Research Grant or Support)GlaxoSmithKline (Research Grant or Support)Melinta Therapeutics, Inc. (Research Grant or Support) Jennifer M. Streit, BS, A. Menarini Industrie Farmaceutiche Riunite S.R.L. (Research Grant or Support)A. Menarini Industrie Farmaceutiche Riunite S.R.L. (Research Grant or Support)Allergan (Research Grant or Support)Melinta Therapeutics, Inc. (Research Grant or Support)Melinta Therapeutics, Inc. (Research Grant or Support)Melinta Therapeutics, Inc. (Research Grant or Support)Merck (Research Grant or Support)Paratek Pharma, LLC (Research Grant or Support) Mariana Castanheira, PhD, 1928 Diagnostics (Research Grant or Support)A. Menarini Industrie Farmaceutiche Riunite S.R.L. (Research Grant or Support)Allergan (Research Grant or Support)Allergan (Research Grant or Support)Amplyx Pharmaceuticals (Research Grant or Support)Cidara Therapeutics (Research Grant or Support)Cidara Therapeutics (Research Grant or Support)Cipla Ltd. (Research Grant or Support)Cipla Ltd. (Research Grant or Support)Fox Chase Chemical Diversity Center (Research Grant or Support)GlaxoSmithKline (Research Grant or Support)Melinta Therapeutics, Inc. (Research Grant or Support)Melinta Therapeutics, Inc. (Research Grant or Support)Melinta Therapeutics, Inc. (Research Grant or Support)Merck (Research Grant or Support)Merck (Research Grant or Support)Merck & Co, Inc. (Research Grant or Support)Merck & Co, Inc. (Research Grant or Support)Paratek Pharma, LLC (Research Grant or Support)Pfizer (Research Grant or Support)Qpex Biopharma (Research Grant or Support) Robert K. Flamm, PhD, A. Menarini Industrie Farmaceutiche Riunite S.R.L. (Research Grant or Support)Amplyx Pharmaceuticals (Research Grant or Support)Basilea Pharmaceutica International, Ltd (Research Grant or Support)Department of Health and Human Services (Research Grant or Support)Melinta Therapeutics, Inc. (Research Grant or Support)

1629. Vancomycin Resistance in Enterococcus faecium Clinical Isolates Responsible for Bloodstream Infections in US Hospitals Over Ten Years (2010-2019) and Activity of Oritavancin

Background

Enterococcus faecium (EFM) causes difficult-to-treat infections due to its intrinsic resistance (R) and ability to acquire R to many antimicrobials. This study evaluated the vancomycin (VAN)-R rates over time and the activity of oritavancin (ORI) against a collection of EFM causing bloodstream infections (BSI).

Methods

A total of 1,081 BSI EFM isolates collected from 36 US hospitals in a prevalence mode design during 2010-2019 were evaluated. Bacterial identification was confirmed by MALDI-TOF MS. Susceptibility testing was performed by reference broth microdilution. For comparison, the ORI breakpoint for VAN-susceptible E. faecalis was applied to EFM. Isolates were characterized as VanA or VanB phenotypes based on their susceptibility (S) to VAN and teicoplanin (TEC). The VanB phenotype was confirmed by PCR and/or whole genome sequencing.

Results

Overall, 72.3% (782/1,081) of EFM were VAN-R (Table). VanA was the most common phenotype (97.7%; 764/782). The yearly VAN-R rates decreased from 81.8% in 2010 to 58.7% in 2019. A total of 18 (2.3%) isolates exhibited a VanB phenotype (TEC MIC, 0.5-8 mg/L); however, the vanB gene only was confirmed in 9 EFM isolates (TEC MIC, 0.5-1 mg/L), which were all collected in 2010-2012. The remaining 9 (50.0%) VanB phenotype EFM isolates carried a vanA gene (TEC MIC, 4-8 mg/L). ORI was very active against VAN-susceptible EFM (MIC50/90, ≤ 0.008/≤0.008/mg/L), VanA (MIC50/90, 0.03/0.12 mg/L; MIC100, 0.5 mg/L), and VanB (MIC50/90, ≤ 0.008/0.015 mg/L; MIC100, 0.03 mg/L) subsets. Only linezolid (LZD) and ORI (MIC, ≤ 0.12 mg/L) showed &gt; 95.0%S against EFM and VAN-R subsets. Daptomycin (DAP)-R rarely was observed (0.8%), but it was more frequently found in the last 5 years. However, 49.9% of EFM isolates showed elevated DAP MICs (2 and 4 mg/L). ORI inhibited 77.8%, and 100.0% of DAP-R and LZD-nonsusceptible EFM isolates at ≤ 0.12 mg/L, respectively.

Conclusion

VAN-R rates among EFM causing BSI in the US decreased during 2010-2019. VanA remains the most common phenotype, whereas vanB-carrying isolates became rarer in later years. Interestingly, half of VanB-phenotype isolates carried a vanA gene. ORI was very active against EFM causing BSI, including isolates R to VAN, DAP, and/or nonsusceptible to LZD.

Table 1

Disclosures

Cecilia G. Carvalhaes, MD, PhD, A. Menarini Industrie Farmaceutiche Riunite S.R.L. (Research Grant or Support)Allergan (Research Grant or Support)Cidara Therapeutics (Research Grant or Support)Cipla Ltd. (Research Grant or Support)Fox Chase Chemical Diversity Center (Research Grant or Support)Melinta Therapeutics, Inc. (Research Grant or Support)Merck (Research Grant or Support)Merck (Research Grant or Support)Merck & Co, Inc. (Research Grant or Support)Pfizer (Research Grant or Support) Helio S. Sader, MD, PhD, A. Menarini Industrie Farmaceutiche Riunite S.R.L. (Research Grant or Support)Allergan (Research Grant or Support)Allergan (Research Grant or Support)Allergan (Research Grant or Support)Cipla Ltd. (Research Grant or Support)Cipla Ltd. (Research Grant or Support)Melinta (Research Grant or Support)Merck (Research Grant or Support)Merck (Research Grant or Support)Paratek Pharma, LLC (Research Grant or Support)Pfizer (Research Grant or Support) Jennifer M. Streit, BS, A. Menarini Industrie Farmaceutiche Riunite S.R.L. (Research Grant or Support)A. Menarini Industrie Farmaceutiche Riunite S.R.L. (Research Grant or Support)Allergan (Research Grant or Support)Melinta Therapeutics, Inc. (Research Grant or Support)Melinta Therapeutics, Inc. (Research Grant or Support)Melinta Therapeutics, Inc. (Research Grant or Support)Merck (Research Grant or Support)Paratek Pharma, LLC (Research Grant or Support) Mariana Castanheira, PhD, 1928 Diagnostics (Research Grant or Support)A. Menarini Industrie Farmaceutiche Riunite S.R.L. (Research Grant or Support)Allergan (Research Grant or Support)Allergan (Research Grant or Support)Amplyx Pharmaceuticals (Research Grant or Support)Cidara Therapeutics (Research Grant or Support)Cidara Therapeutics (Research Grant or Support)Cipla Ltd. (Research Grant or Support)Cipla Ltd. (Research Grant or Support)Fox Chase Chemical Diversity Center (Research Grant or Support)GlaxoSmithKline (Research Grant or Support)Melinta Therapeutics, Inc. (Research Grant or Support)Melinta Therapeutics, Inc. (Research Grant or Support)Melinta Therapeutics, Inc. (Research Grant or Support)Merck (Research Grant or Support)Merck (Research Grant or Support)Merck & Co, Inc. (Research Grant or Support)Merck & Co, Inc. (Research Grant or Support)Paratek Pharma, LLC (Research Grant or Support)Pfizer (Research Grant or Support)Qpex Biopharma (Research Grant or Support) Rodrigo E. Mendes, PhD, A. Menarini Industrie Farmaceutiche Riunite S.R.L. (Research Grant or Support)Allergan (Research Grant or Support)Allergan (Research Grant or Support)Basilea Pharmaceutica International, Ltd (Research Grant or Support)Cipla Ltd. (Research Grant or Support)Department of Health and Human Services (Research Grant or Support)GlaxoSmithKline (Research Grant or Support)Melinta Therapeutics, Inc. (Research Grant or Support)Merck (Research Grant or Support)Merck (Research Grant or Support)Pfizer (Research Grant or Support)

1463. Activity of Delafloxacin against Multi-Drug-Resistant Fastidious Respiratory Pathogens from European Medical Centers (2014-2019)

Background

Delafloxacin (DLX) is an anionic fluoroquinolone (FQ) that has been approved in the United States and in Europe for the treatment of acute bacterial skin and skin structure infections and was recently approved in the US for treatment of community-acquired bacterial pneumonia (CABP). In the present study, in vitro susceptibility (S) results for DLX and comparator agents were determined for CABP pathogens including Streptococcus pneumoniae (SPN), Haemophilus influenzae (HI), H. parainfluenzae (HP) and Moraxella catarrhalis (MC) clinical isolates from European hospitals participating in the SENTRY Program during 2014-2019.

Methods

A total of 2,835 SPN, 1,484 HI, 959 MC, and 20 HP isolates were collected from community-acquired respiratory tract infections (CARTI) during 2014-2019 from European hospitals. Sites included only 1 isolate/patient/infection episode. Isolate identifications were confirmed at JMI Laboratories. Susceptibility testing was performed according to CLSI broth microdilution methodology, and EUCAST (2020) breakpoints were applied where applicable. Other antimicrobials tested included levofloxacin (LEV) and moxifloxacin (MOX; not tested in 2015). Multidrug-resistant (MDR) SPN isolates were categorized as being nonsusceptible (NS) to amoxicillin-clavulanate, erythromycin (ERY), and tetracycline; other SPN phenotypes were ERY-NS, or penicillin (PEN)-NS. β-lactamase (BL) presence was determined for HI, HP, and MC.

Results

The activities of the 3 FQs are shown in the table. The most active agent against SPN was DLX, with the lowest MIC50/90 values of 0.015/0.03 mg/L. DLX activities were the same when tested against the MDR or PEN-NS for SPN phenotypes. ERY-NS isolates had DLX MIC50/90 results of 0.015/0.03 mg/L. DLX was the most active FQ against HI, HP, and MC. BL presence did not affect FQ MIC values for HI or MC; only 1 HP isolate was BL-positive.

Conclusion

DLX demonstrated potent in vitro antibacterial activity against SPN, HI, HP, and MC. DLX was active against MDR SPN that were NS to the agents commonly used as treatments for CABP. These data support the utility of DLX in CABP including when caused by antibiotic resistant strains.

Table 1

Disclosures

Jennifer M. Streit, BS, A. Menarini Industrie Farmaceutiche Riunite S.R.L. (Research Grant or Support)A. Menarini Industrie Farmaceutiche Riunite S.R.L. (Research Grant or Support)Allergan (Research Grant or Support)Melinta Therapeutics, Inc. (Research Grant or Support)Melinta Therapeutics, Inc. (Research Grant or Support)Melinta Therapeutics, Inc. (Research Grant or Support)Merck (Research Grant or Support)Paratek Pharma, LLC (Research Grant or Support) Robert K. Flamm, PhD, A. Menarini Industrie Farmaceutiche Riunite S.R.L. (Research Grant or Support)Amplyx Pharmaceuticals (Research Grant or Support)Basilea Pharmaceutica International, Ltd (Research Grant or Support)Department of Health and Human Services (Research Grant or Support)Melinta Therapeutics, Inc. (Research Grant or Support)

1253. In Vitro Activity of Omadacycline against 7000 Bacterial Pathogens from the United States Stratified by Infection Type (2019)

Background

Omadacycline (OMC) is a new aminomethylcycline antibacterial drug belonging to the tetracycline class, for intravenous or oral administration. It is well tolerated and has proven effective in the treatment of a variety of bacterial infections. OMC is active against bacterial strains expressing the most common clinically relevant tetracycline resistance mechanisms, namely efflux and ribosomal protection.

Methods

7,000 clinical isolates were collected during 2019 in the SENTRY Surveillance Program from 31 medical centers in the United States (US). Isolates were obtained from bloodstream infection (23.8%), skin and skin structure infection (21.6%), pneumonia in hospitalized patients (22.7%), urinary tract infection (14.5%), intraabdominal infection (6.2%), community acquired respiratory tract infection (10.3%) and other infection types (0.9%). Identifications were confirmed by MALDI-TOF. One isolate/patient/infection episode was tested. Broth microdilution susceptibility testing was conducted according to CLSI M07 (2018) and M100 (2020) guidelines. Results were interpreted using US FDA and CLSI breakpoint criteria.

Results

OMC demonstrated potent in vitro activity against Staphylococcus aureus isolates representing multiple infection types (MIC₉₀, 0.12-0.25 mg/L; 94.7%-99.0% susceptible [S]) including MRSA (MIC₉₀, 0.25 mg/L; 96.5% S) (Table). All S. lugdunensis (MIC₉₀, 0.06 mg/L), Enterococcus faecalis (MIC₉₀, 0.12-0.25 mg/L), and Haemophilus influenzae (MIC₉₀, 1 mg/L) isolates were S to OMC. OMC was active against Streptococcus pyogenes isolates from SSSI (MIC₉₀, 0.12 mg/L; 93.3%-98.5%S) including macrolide-resistant (R) strains. Similarly, S. pneumoniae isolates from RTI were S to OMC (MIC₉₀, 0.06-0.12 mg/L; 98.8%-100%S) regardless of resistance to tetracycline or penicillin. Overall, 90.2%-93.6% of Enterobacter cloacae (MIC₉₀, 4 mg/L) and 89.7%-94.7% of Klebsiella pneumoniae (MIC₉₀, 4-8 mg/L) isolates from multiple infection types were S to OMC.

Conclusion

OMC demonstrated potent in vitro activity against Gram-positive and -negative bacterial pathogens from multiple infection types including SSSI and RTI and isolates displaying resistance to tetracycline, macrolides, and penicillin.

Table 1

Disclosures

Michael A. Pfaller, MD, Amplyx Pharmaceuticals (Research Grant or Support)Basilea Pharmaceutica International, Ltd (Research Grant or Support)Cidara Therapeutics (Research Grant or Support)Cidara Therapeutics (Research Grant or Support)Department of Health and Human Services (Research Grant or Support)Fox Chase Chemical Diversity Center (Research Grant or Support)Paratek Pharma, LLC (Research Grant or Support) Jennifer M. Streit, BS, A. Menarini Industrie Farmaceutiche Riunite S.R.L. (Research Grant or Support)A. Menarini Industrie Farmaceutiche Riunite S.R.L. (Research Grant or Support)Allergan (Research Grant or Support)Melinta Therapeutics, Inc. (Research Grant or Support)Melinta Therapeutics, Inc. (Research Grant or Support)Melinta Therapeutics, Inc. (Research Grant or Support)Merck (Research Grant or Support)Paratek Pharma, LLC (Research Grant or Support) Helio S. Sader, MD, PhD, A. Menarini Industrie Farmaceutiche Riunite S.R.L. (Research Grant or Support)Allergan (Research Grant or Support)Allergan (Research Grant or Support)Allergan (Research Grant or Support)Cipla Ltd. (Research Grant or Support)Cipla Ltd. (Research Grant or Support)Melinta (Research Grant or Support)Merck (Research Grant or Support)Merck (Research Grant or Support)Paratek Pharma, LLC (Research Grant or Support)Pfizer (Research Grant or Support) Mariana Castanheira, PhD, 1928 Diagnostics (Research Grant or Support)A. Menarini Industrie Farmaceutiche Riunite S.R.L. (Research Grant or Support)Allergan (Research Grant or Support)Allergan (Research Grant or Support)Amplyx Pharmaceuticals (Research Grant or Support)Cidara Therapeutics (Research Grant or Support)Cidara Therapeutics (Research Grant or Support)Cipla Ltd. (Research Grant or Support)Cipla Ltd. (Research Grant or Support)Fox Chase Chemical Diversity Center (Research Grant or Support)GlaxoSmithKline (Research Grant or Support)Melinta Therapeutics, Inc. (Research Grant or Support)Melinta Therapeutics, Inc. (Research Grant or Support)Melinta Therapeutics, Inc. (Research Grant or Support)Merck (Research Grant or Support)Merck (Research Grant or Support)Merck & Co, Inc. (Research Grant or Support)Merck & Co, Inc. (Research Grant or Support)Paratek Pharma, LLC (Research Grant or Support)Pfizer (Research Grant or Support)Qpex Biopharma (Research Grant or Support)

Antimicrobial activity of dalbavancin against clinical isolates of coagulase-negative staphylococci from the USA and Europe stratified by species

OBJECTIVES

To evaluate the in vitro activity of dalbavancin compared with vancomycin, daptomycin and other agents against a large collection of coagulase-negative staphylococci (CoNS) isolates.

METHODS

A total of 5088 CoNS causing clinically significant infection were consecutively collected from 122 medical centres in the USA and Europe over 6 years (2014-2019). Isolates were tested for susceptibility by the reference broth microdilution method. Species identification was confirmed by MALDI-TOF. Most isolates were from bloodstream infections (BSIs) (53.5%) or skin/skin structure infections (28.5%).

RESULTS

Staphylococcus epidermidis was the most common species overall (54.6%) and for BSI (61.3%). The second most common species were Staphylococcus lugdunensis overall (12.3%) and Staphylococcus hominis for BSI (14.7%). Dalbavancin (MIC_50/90, 0.03/0.06 mg/L) inhibited >99.9% of CoNS isolates at ≤0.25 mg/L (susceptible breakpoint for Staphylococcus aureus per CLSI). All species were inhibited at ≤0.25 mg/L dalbavancin, except some S. epidermidis (>99.9%) and Staphylococcus warneri (98.9%) isolates. Staphylococcus capitis and Staphylococcus simulans exhibited the lowest dalbavancin MIC_50/90 values (0.015/0.03 mg/L) and Staphylococcus haemolyticus and Staphylococcus saprophyticus the highest (MIC_50/90, 0.06/0.12 mg/L); 47.8% of S. epidermidis and 34.7% of S. haemolyticus exhibited decreased susceptibility to vancomycin (MIC ≥ 2 mg/L) and 23.2% of S. capitis and 28.4% of S. warneri showed decreased susceptibility to daptomycin (MIC ≥ 1 mg/L).

CONCLUSION

Antimicrobial susceptibility varied widely among CoNS species. Dalbavancin inhibited >99.9% and 99.1% of isolates at the US-FDA and EUCAST breakpoints, respectively. Clinical studies of dalbavancin for treatment of CoNS infections should be considered based on these in vitro data.

Frequency and antimicrobial susceptibility of bacteria causing bloodstream infections in pediatric patients from United States (US) medical centers (2014-2018): therapeutic options for multidrug-resistant bacteria

Studies evaluating large series of pediatric patients with bloodstream infections (BSIs) are scarce. We evaluated the frequency and antimicrobial susceptibility of organisms isolated from pediatric patients with BSI and therapeutic options for BSI caused by multidrug-resistant (MDR) organisms. A total of 2423 organisms were consecutively collected from 33 US medical centers between 2014 and 2018, and susceptibility was tested by reference broth microdilution methods. Isolates with an extended-spectrum β-lactamase phenotype were screened for β-lactamase genes. Overall, 40.2% of organisms were Gram-negative bacteria, 57.0% Gram-positives, and 2.8% Candida spp. The 5 most common organisms were Staphylococcus aureus (26.0%), Escherichia coli (13.0%), coagulase-negative staphylococci (8.3%), Enterococcus faecalis (7.1%), and Klebsiella pneumoniae (6.9%). Among S. aureus, 26.0% were oxacillin-resistant and 99.8% were susceptible to ceftaroline (MIC50/90, 0.25/0.5 mg/L). Enterobacterales and Pseudomonas aeruginosa isolates combined represented >85% of Gram-negative bacteria, and all isolates (100.0%) were susceptible to ceftazidime-avibactam.

Activity of ceftolozane-tazobactam and comparators when tested against bacterial surveillance isolates collected from patients at risk of infections caused by resistant gram-negative pathogens

Ceftolozane-tazobactam is an antipseudomonal cephalosporin combined with a β-lactamase inhibitor. Ceftolozane-tazobactam has been approved for treatment of complicated urinary tract infections and acute pyelonephritis, for complicated intra-abdominal infections (with metronidazole) in adults, and for hospital-acquired bacterial pneumonia including ventilator-associated bacterial pneumonia. This study analyzed gram-negative pathogen susceptibility in US and European patients who are considered at risk for infections caused by pathogens resistant to commonly used antimicrobials: patients in the intensive care unit (ICU), patients on the hematology/oncology or transplant service who may be immunocompromised, and patients >65 years old (yo). ICU patients had the lowest susceptibility for Enterobacterales and PSA. The susceptibility for isolates from the immunocompromised and >65 yo groups was similar. Ceftolozane-tazobactam was the most active agent against PSA, with ≥90%S for >65 yo and immunocompromised, and >80%S for ICU. Meropenem and ceftolozane-tazobactam were the most active agents against Enterobacterales.

Update on the in vitro activity of dalbavancin against indicated species (Staphylococcus aureus, Enterococcus faecalis, β-hemolytic streptococci, and Streptococcus anginosus group) collected from United States hospitals in 2017-2019

This study updates dalbavancin activity against contemporary (2017-2019) isolates of indicated species/groups (n = 16,451). Isolates from 71 hospitals were tested by broth microdilution method. All isolates were susceptible to dalbavancin. Dalbavancin MIC_50/90 values remained stable for Staphylococcus aureus, vancomycin-susceptible Enterococcus faecalis, β-hemolytic streptococci, and Streptococcus anginosus group since its clinical approval.

Antimicrobial Activity of Ceftazidime-Avibactam, Ceftolozane-Tazobactam and Comparators Tested Against Pseudomonas aeruginosa and Klebsiella pneumoniae Isolates from United States Medical Centers in 2016-2018

Very few antimicrobial agents remain active against Pseudomonas aeruginosa and Klebsiella pneumoniae in some geographic regions. We evaluated the in vitro activity of ceftazidime-avibactam, ceftolozane-tazobactam, and comparator agents against 6,210 P. aeruginosa and 6,041 K. pneumoniae isolates consecutively collected from 85 U.S. medical centers across 37 states in 2016-2018. Antimicrobial susceptibility was determined by reference broth microdilution method. K. pneumoniae isolates found to have elevated MICs for broad-spectrum cephalosporins were submitted to whole-genome sequencing analysis to detect resistance genes. Ceftazidime-avibactam (97.1% susceptible [S]) and ceftolozane-tazobactam (97.0%S) were the most active compounds against P. aeruginosa and retained activity against meropenem-nonsusceptible (88.5-89.0%S), piperacillin-tazobactam-nonsusceptible (86.6-87.0%S), and other resistant subsets of isolates. The most active agents against K. pneumoniae per CLSI criteria were ceftazidime-avibactam (>99.9%S), amikacin (98.4%S), and meropenem (97.1%S). Ceftolozane-tazobactam was active against 95.3% of K. pneumoniae but showed limited activity against extended-spectrum β-lactamase and carbapenemase producers (82.9% and 0.0%S, respectively).

1582. Delafloxacin Activity Against Drug-Resistant Streptococcus pneumoniae, Haemophilus influenzae, Haemophilus parainfluenzae, and Moraxella catarrhalis from US Medical Centers (2014–2018)

Background

Delafloxacin (DLX) is an anionic fluoroquinolone (FQ) antimicrobial that was approved in 2017 by the United States (US) Food and Drug Administration for the treatment of acute bacterial skin and skin structure infections. DLX recently successfully completed a clinical trial for the treatment of community-acquired bacterial pneumonia (CABP). In the present study, in vitro susceptibility (S) results for DLX and comparator agents were determined for CABP pathogens including Streptococcus pneumoniae (SPN), Haemophilus influenzae (HI), H. parainfluenzae (HP) and Moraxella catarrhalis (MC) clinical isolates from US hospitals participating in the SENTRY Program during 2014–2018.

Methods

A total of 1,975 SPN, 1,128 HI, 684 MC, and 43 HP isolates were collected from community-acquired respiratory tract infections (CARTI) during 2014–2018 from US hospitals. Sites included only 1 isolate/patient/infection episode. Isolate identifications were confirmed at JMI Laboratories. Susceptibility testing was performed according to CLSI broth microdilution methodology, and CLSI (2019) breakpoints were applied where applicable. Other antimicrobials tested included levofloxacin (LEV) and moxifloxacin (MOX; not tested in 2015). Multidrug-resistant (MDR) SPN isolates were categorized as being nonsusceptible (NS) to amoxicillin-clavulanate, erythromycin, and tetracycline; other SPN phenotypes were LEV-NS or penicillin (PEN)-NS. β-Lactamase (BL) presence was determined for HI, HP, and MC.

Results

The activities of the 3 FQs are shown in the table. The most active agent against SPN was DLX, with the lowest MIC50/90 values of 0.015/0.03 mg/L. DLX activities were similar when tested against the MDR or PEN-NS for SPN phenotypes. LEV-NS isolates had DLX MIC50/90 results of 0.12/0.25 mg/L. DLX was the most active FQ against HI, HP, and MC. BL presence did not affect FQ MIC values for HI or MC; only 2 HP isolates were BL-positive.

Conclusion

DLX demonstrated potent in vitro antibacterial activity against SPN, HI, HP, and MC. DLX was active against MDR SPN that were NS to the agents commonly used as treatments for CABP. DLX had excellent activity against LEV-NS SPN. These data support the continued study of DLX as a potential treatment for CABP.

Disclosures

All authors: No reported disclosures.

1584. Minocycline Activity Against Stenotrophomonas maltophilia Isolated From Patients in US Hospitals

Background

Stenotrophomonas maltophilia (SM) has emerged as a common hospital-associated opportunistic pathogen found in immunocompromised and immunocompetent patients. SM is intrinsically resistant to many common drug classes, including carbapenems, cephalosporins, and aminoglycosides. Only 4 antibiotics have CLSI breakpoints for SM: minocycline (MIN), ceftazidime (CAZ), levofloxacin (LVX) and trimethoprim-sulfamethoxazole (TMP-SMX). Minocycline is frequently used to treat SM infections. In this study, we analyzed susceptibilities of SM isolates collected as part of the SENTRY Program. We also examined the frequency of SM isolation from pneumonia in hospitalized patients (PIHP) among all Gram-negative (GN) species.

Methods

From 2014 to 2018, 990 SM isolates were collected from hospitalized patients in 32 US hospitals. Hospitals submitted 1 isolate per patient per infection episode that met local criteria for being the likely causative pathogen and submitted consecutive isolates from pneumonia. Isolates were tested for MIN susceptibility (S) using the CLSI broth microdilution method at JMI Laboratories. Other antimicrobials tested were CAZ, LVX, and TMP-SMX. TMP-SMX was tested 3 of 5 years. All infection types were included in the susceptibility analysis. The prevalence of SM isolates in PIHP during this period was also analyzed.

Results

There were 9,120 GN pathogens isolated from PIHP. The most commonly isolated species was P. aeruginosa (34.7%), followed by Klebsiella pneumoniae (12.6%), Escherichia coli (10.1%), and SM (7.9%). Among the 990 infections caused by SM, PIHP was the most common at 72.4%, followed by bloodstream infections (14.4%) and skin/skin structure infections (6.9%). The %S and MIC50/90 values of the 4 antimicrobials tested in this study are shown in the table.

Conclusion

SM was the fourth most frequent cause of GN PIHP in US medical centers. MIN was the most active drug tested against SM with 99.5%S, followed by TMP-SMX (94.7%), and CAZ was the least active with 28.5%S. This study suggests that MIN may be a consideration as a treatment for infections caused by SM, with a very low resistance rate based on CLSI breakpoints.

Disclosures

All authors: No reported disclosures.

1589. Ceftolozane–Tazobactam Activity Against Difficult-to-Treat Resistance in Pseudomonas aeruginosa from Bloodstream Infections in US Hospitals

Background

Infections caused by Pseudomonas aeruginosa (PSA) resistant to first-line agents are difficult to treat and require using more toxic antimicrobials, such as amikacin (AMK) and colistin (COL). Kadri et al. recently described the category of difficult-to-treat resistance (DTR) as intermediate or resistant to all tested first-line agents (fluoroquinolones, carbapenems, and extended-spectrum cephalosporins). Ceftolozane–tazobactam (C-T) is an antibacterial combination of an antipseudomonal cephalosporin and a β-lactamase inhibitor. C-T has been approved in >60 countries to treat complicated urinary tract infections, acute pyelonephritis, and complicated intra-abdominal infections. The filing is in progress for treatment of hospital-acquired pneumonia, including ventilator-associated pneumonia. The Program to Assess Ceftolozane–Tazobactam Susceptibility (PACTS) monitors gram-negative (GN) isolates resistant to C-T worldwide. In this study, the activity of C-T and comparators against PSA bloodstream isolates that are DTR, multidrug-resistant (MDR), or extensively drug-resistant (XDR) were analyzed.

Methods

A total of 922 PSA isolates from BSI were collected between 2011 and 2018 from 35 PACTS hospitals in the United States. Isolates were tested for C-T susceptibility (S) by the CLSI broth microdilution method. Other antibiotics tested included cefepime (FEP), ceftazidime (CAZ), ciprofloxacin, levofloxacin (LEV), doripenem, imipenem, meropenem (MEM), piperacillin–tazobactam (PIP-TAZ), AMK and COL. Antibiotic-resistant phenotypes analyzed using CLSI (2019) breakpoints included MDR (nonsusceptible to ≥ 1 agent in ≥ 3 drug classes), XDR (susceptible to ≤ 1 agent in ≤ 2 drug classes), or DTR.

Results

The percent of DTR isolates was 4.8% when compared with 15.2% MDR and 9.3% XDR. The %S for C-T and other first- and second-line agents are shown in the table for each phenotype.

Conclusion

C-T demonstrated 97.1%S overall for BSI isolates, similar to AMK (97.8%) and COL (99.5%). C-T had better coverage than first-line drugs against MDR (81.4%) and XDR (72.1%), and 50% for the DTR isolates, which represented only 4.8% of isolates. Only AMK and COL had > 75%S for DTR isolates.

Disclosures

All authors: No reported disclosures.