Deaths attributable to carbapenem-resistant Enterobacteriaceae infections

Changing epidemiology and antimicrobial resistance of bacteria causing bacteremia in Taiwan: 2002-2020

Bacteremia is associated with significant morbidity and mortality. The emergence of bacteria with antimicrobial resistance (AMR) has further exacerbated the poor outcomes associated with bacteremia. The Taiwan Surveillance of Antimicrobial Resistance (TSAR) program was established in 1998 to monitor bacterial epidemiology and antimicrobial resistance trends across all patient types and age groups. Between 2002 and 2020, a total of 14,539 non-duplicate bacteremia isolates were collected biennially from 29 hospitals during the months of July-September as part of the TSAR program. The three most common bacteremia agents were Escherichia coli (31%), Staphylococcus aureus (13.6%), and Klebsiella pneumoniae (12.7%) overall. However, there was a steady increase in the proportions of E. coli and Enterococcus faecium isolated from bacteremia cases (both P < 0.001), while the proportions of Acinetobacter spp. decreased. Regarding antimicrobial resistance, there was a notable increase in rates of third-generation cephalosporin and fluoroquinolone non-susceptibility among E. coli and K. pneumoniae, while the rates of carbapenem non-susceptibility were elevated but remained milder in these two species, especially in E. coli. Of concern is the alarming increase in vancomycin resistance among E. faecium, rising from 10.0% in 2004 to 47.7% in 2020. In contrast, the prevalence of methicillin-resistant S. aureus has remained stable at 51.2% overall. In conclusion, E. coli, with increasing third-generation cephalosporin and fluoroquinolone resistance, is the predominant cause of bacteremia in Taiwan during the 18-year surveillance. The escalating proportion of E. faecium in bacteremia, coupled with a concurrent upsurge in vancomycin resistance, presents a therapeutic challenge in the recent decade.

IMPORTANCE

AMR surveillance not only enables the identification of regional variations but also supports the development of coordinated efforts to combat AMR on a global scale. The TSAR has been a biennial, government-endorsed, multicenter study focusing on pathogens isolated from inpatients and outpatients in Taiwan hospitals since 1998. Our report presents an 18-year comprehensive analysis on blood isolates in the 2002-2020 TSAR program. The study highlights an alarming increase in the proportion of E. faecium causing bacteremia accompanied by elevated vancomycin resistance. It is worth noting that this trend differs from the observations in the United States and China. Understanding the composition of bacteria causing bacteremia, along with their prevalence of antimicrobial resistance, holds significant importance in establishing healthcare and research priorities. Additionally, this knowledge serves as a critical factor in evaluating the effectiveness of preventive interventions.

Ceftazidime-Avibactam as a Salvage Treatment for Severely Infected Immunosuppressed Children

Background

Multidrug-resistant Gram-negative bacteria (MDR-GNB) are becoming increasingly common around the world, with carbapenems frequently serving as a last resort but being threatened by the growing incidence of carbapenemase-producing bacteria. Ceftazidime-avibactam (CAZ/AVI) is a potential agent against MDR-GNB but with limited clinical experience, particularly in critically ill immunosuppressed children.

Methods

This study analyzed the use of CAZ/AVI as salvage treatment in severely infected immunosuppressed children from September 2019 to July 2022. Patients with confirmed GNB infection who received CAZ/AVI were matched with patients who received other antibiotics.

Results

Twenty-five critically ill immunosuppressed children treated with CAZ/AVI were included. The majority had hematologic diseases. All patients presented with sepsis in all 30 courses. Septic shock presented in 36.7% of these courses. The primary sites of infection included bloodstream infection (20.0%), skin and skin structure infection (20.0%), intra-abdominal infection (13.3%) and hospital-acquired pneumonia (10.0%). Twelve of the 25 (48.0%) patients had positive microbiological cultures, mainly Pseudomonas aeruginosa and Klebsiella pneumoniae, including 5 carbapenem-resistant GNB-infected cases. Fifteen (50.0%) courses presented clinical improvement. For the initial course of each patient, the clinical response rate of the GNB recovered group was significantly higher than that of the group without GNB recovery (66.7% vs 23.1%, P = 0.047). The 14-day and 30-day mortality rates were 24.0% and 28.0%, respectively, which were significantly correlated with the absence of GNB recovery (P = 0.004 and 0.024, respectively) and hospital-acquired pneumonia as the primary site of infection (P = 0.001 and 0.006, respectively). There was no significant difference in major outcomes between patients who received CAZ/AVI and matched patients who received other antibiotics.

Conclusion

CAZ/AVI could be considered a salvage strategy for immunosuppressed children with confirmed GNB infection. Caution should be taken when CAZ/AVI is applied to these patients in the absence of GNB recovery.

Effects of meropenem supply restriction: A multicenter retrospective study

BACKGROUND

In Japan, the supply of one generic meropenem product was restricted from August 2022 to March 2023.

OBJECTIVE

To determine the effects of meropenem (MEPM) restriction.

METHODS

We conducted a multicenter retrospective study comparing antimicrobial use, bacteremia mortality, and drug-resistant bacteria detected before the restriction of MEPM (control period), from September 2021 to February 2022, and after the restriction of MEPM (MEPM supply restriction period), from September 2022 to February 2023, in five institutions.

RESULTS

The number of carbapenem days of therapy (DOTs) were decreased in all five institutions. Fourth-generation cephalosporin DOTs increased in all facilities, and piperacillin/tazobactam DOTs increased in four facilities. The 30-day and 90-day mortality rates were significantly higher during the MEPM supply restriction period than those during the control period. Moreover, survival time was significantly shorter during the MEPM supply restriction period than that during the control period. Multivariable analysis revealed that MEPM supply restriction, age >80 years, Pitt Bacteremia Score ≥4, platelet count <10 × 104/μL, serum albumin level <2.5 g/dL, and methicillin-resistant Staphylococcus aureus bloodstream infection were independent risk factors for 30-day mortality. The detection rates of carbapenem-resistant Pseudomonas aeruginosa and Enterobacteriaceae did not differ significantly between the two periods.

CONCLUSIONS

MEPM supply restriction decreased the use of carbapenems and increased the use of other broad-spectrum antimicrobial agents, which worsened the prognosis of bacteremia. Overall, carbapenems are important drugs for the treatment of infectious diseases and are difficult to replace in unforeseen situations such as drug supply outages.

VirBR, a transcription regulator, promotes IncX3 plasmid transmission, and persistence of blaNDM-5 in zoonotic bacteria

IncX3 plasmids carrying the New Delhi metallo-β-lactamase-encoding gene, blaNDM-5, are rapidly spreading globally in both humans and animals. Given that carbapenems are listed on the WHO AWaRe watch group and are prohibited for use in animals, the drivers for the successful dissemination of Carbapenem-Resistant Enterobacterales (CRE) carrying blaNDM-5-IncX3 plasmids still remain unknown. We observe that E. coli carrying blaNDM-5-IncX3 can persist in chicken intestines either under the administration of amoxicillin, one of the largest veterinary β-lactams used in livestock, or without any antibiotic pressure. We therefore characterise the blaNDM-5-IncX3 plasmid and identify a transcription regulator, VirBR, that binds to the promoter of the regulator gene actX enhancing the transcription of Type IV secretion systems (T4SS); thereby, promoting conjugation of IncX3 plasmids, increasing pili adhesion capacity and enhancing the colonisation of blaNDM-5-IncX3 transconjugants in animal digestive tracts. Our mechanistic and in-vivo studies identify VirBR as a major factor in the successful spread of blaNDM-5-IncX3 across one-health AMR sectors. Furthermore, VirBR enhances the plasmid conjugation and T4SS expression by the presence of copper and zinc ions, thereby having profound ramifications on the use of universal animal feeds.

Distribution and molecular characterization of carbapenemase-producing gram-negative bacteria in Henan, China

This study aimed to investigate the epidemiological characteristics and trends over time of carbapenemase-producing (e.g., KPC, NDM, VIM, IMP, and OXA-48) Gram-negative bacteria (CPGNB). Non-duplicated multi-drug resistant Gram-negative bacteria (MDRGNB) were collected from the First Affiliated Hospital of Zhengzhou University from April 2019 to February 2023. Species identification of each isolate was performed using the Vitek2 system and confirmed by matrix-assisted laser desorption ionization-time of flight mass spectrometry according to the manufacturer's instructions. PCR detected carbapenem resistance genes in the strains, strains carrying carbapenem resistance genes were categorized as CPGNB strains after validation by carbapenem inactivation assay. A total of 5705 non-repetitive MDRGNB isolates belonging to 78 different species were collected during the study period, of which 1918 CPGNB were validated, with the respiratory tract being the primary source of specimens. Epidemiologic statistics showed a significant predominance of ICU-sourced strains compared to other departments. Klebsiella pneumoniae, Escherichia coli, Acinetobacter baumannii, and Pseudomonas aeruginosa were the significant CPGNB in Henan, and KPC and NDM were the predominant carbapenemases. Carbapenem-resistant infections in Henan Province showed an overall increasing trend, and the carriage of carbapenemase genes by CPGNB has become increasingly prevalent and complicated. The growing prevalence of CPGNB in the post-pandemic era poses a significant challenge to public safety.

A predictive score for the result of carbapenem-resistant Enterobacterales and vancomycin-resistant enterococci screening

BACKGROUND

The duration of extensively drug-resistant bacteria (XDR) carriage depends on several factors for which the information can be difficult to recover.

AIM

To determine whether past screening and clinical results of patients can predict the results of subsequent screening.

METHODS

In total, 256 patients were retrospectively included from 10 healthcare centres in France from January 2014 to January 2022. We created a predictive clearance score, ranging from -5 to +7, that included the number of XDR species and the type of resistance detected in the sample, as well as the time from the last positive sample, the number of previous consecutive negative samples, and obtaining at least one negative PCR result in the collection. This score could be used for the upcoming rectal screening of a patient carrying an XDR as soon as the last screening sample was negative.

FINDINGS

The negative predictive value was >99% for score ≤0. The median time to achieve XDR clearance was significantly shorter for a score of 0 (443 days (259-705)) than that based on previously published criteria.

CONCLUSION

This predictive score shows high performance for the assessment of XDR clearance. Relative to previous guidelines, it could help to lift specific infection prevention and control measures earlier. Nevertheless, the decision should be made according to other factors, such as antimicrobial use and adherence to hand hygiene.

Prevalence and Risk Factors for Colonization by Multidrug-Resistant Microorganisms among Long-Term Travelers and Recently Arrived Migrants

Multidrug-resistant (MDR) bacteria have become one of the most important health problems. We aimed to assess whether international travel may facilitate their spread through the colonization of asymptomatic travelers. A cross-sectional study was conducted (November 2018 to February 2022). Pharyngeal and rectal swabs were obtained from long-term travelers and recently arrived migrants from non-European countries, and an epidemiological survey was performed. Colonization by Gram-negative bacteria and methicillin-resistant Staphylococcus aureus (MRSA) was determined by chromogenic media and MALDI-TOF-MS. Resistance mechanisms were determined by the biochip-based molecular biology technique. Risk factors for colonization were assessed by logistic regression. In total, 122 participants were included: 59 (48.4%) recently arrived migrants and 63 (51.6%) long-term travelers. After their trip, 14 (11.5%) participants-5 (8.5%) migrants and 9 (14.3%) travelers-had rectal colonization by one MDR bacterium. Escherichia coli carrying the extended-spectrum beta-lactamase (ESBL) CTX-M-15 was the most frequent. No participants were colonized by MRSA or carbapenemase-producing Enterobacteriaceae. The only risk factor independently associated with MDR bacterial colonization was previous hospital attention [OR, 95% CI: 10.16 (2.06-50.06)]. The risk of colonization by MDR bacteria among recently arrived migrants and long-term travelers is similar in both groups and independently associated with previous hospital attention.

Assessing bacterial prevalence and resistance in paediatric meningitis: safeguarding the central nervous system

Introduction

Paediatric bacterial meningitis (PBM) represents a major contributor to childhood morbidity and mortality globally, with heightened susceptibility in low- and middle-income nations where antimicrobial resistance (AMR) is highly prevalent. Pakistan exemplifies this setting, with widespread antibiotic overuse driving AMR expansion. Thus, expediting PBM diagnosis and targeted antibiotic therapy is imperative yet challenged by the dynamic local epidemiology. This study aimed to delineate the recent bacterial etiologies and AMR profiles of PBM from a major Pakistani diagnostics laboratory to inform empirical treatment.

Materials and methods

This prospective observational investigation evaluated PBM epidemiology in patients under 18 years old admitted to the study hospital. Standard cerebrospinal fluid analysis identified bacterial pathogens and antibiotic susceptibility patterns.

Results

Among 171 PBM cases, 152 (88.9%) had bacterial isolates confirmed via culture. The cohort was 42.7% male with a mean age of 3 months. The most prevalent pathogens among infants younger than 3 months were Escherichia coli, Enterococcus faecium, and Staphylococcus epidermidis, contrasting with S. epidermidis, Streptococcus pneumoniae, and Staphylococcus hominis predominating in older children. Staphylococcal isolates exhibited considerable penicillin and erythromycin resistance but maintained vancomycin and linezolid susceptibility. Other resistance patterns varied.

Conclusion

These findings highlight the pressing threat of paediatric AMR in Pakistan, underscoring the need for vigilant AMR surveillance and judicious antimicrobial use. This study provides a reference to current PBM epidemiology to guide context-specific empirical therapy.

Rates of resistance and heteroresistance to newer β-lactam/β-lactamase inhibitors for carbapenem-resistant Enterobacterales

Background

Heteroresistance (HR), the presence of antibiotic-resistant subpopulations within a primary isogenic population, may be a potentially overlooked contributor to newer β-lactam/β-lactamase inhibitor (BL/BLI) treatment failure in carbapenem-resistant Enterobacterales (CRE) infections.

Objectives

To determine rates of susceptibility and HR to BL/BLIs ceftazidime/avibactam, imipenem/relebactam and meropenem/vaborbactam in clinical CRE isolates.

Methods

The first CRE isolate per patient per year from two >500 bed academic hospitals from 1 January 2016 to 31 December 2021, were included. Reference broth microdilution (BMD) was used to determine antibiotic susceptibility, and population analysis profiling (PAP) to determine HR. Carbapenemase production (CP) was determined using the Carba NP assay.

Results

Among 327 CRE isolates, 46% were Enterobacter cloacae, 38% Klebsiella pneumoniae and 16% Escherichia coli. By BMD, 87% to 98% of CRE were susceptible to the three antibiotics tested. From 2016 to 2021, there were incremental decreases in the rates of susceptibility to each of the three BL/BLIs. HR was detected in each species-antibiotic combination, with the highest rates of HR (26%) found in K. pneumoniae isolates with imipenem/relebactam. HR or resistance to at least one BL/BLI by PAP was found in 24% of CRE isolates and 65% of these had detectable CP.

Conclusion

Twenty-four percent of CRE isolates tested were either resistant or heteroresistant (HR) to newer BL/BLIs, with an overall decrease of ∼10% susceptibility over 6 years. While newer BL/BLIs remain active against most CRE, these findings support the need for ongoing antibiotic stewardship and a better understanding of the clinical implications of HR in CRE.

In vitro activity of aztreonam-avibactam and comparators against Metallo-β-Lactamase-producing Enterobacterales from ATLAS Global Surveillance Program, 2016-2020

OBJECTIVES

Metallo-β-lactamase (MBL)-producing Enterobacterales are a major challenge worldwide due to limited treatment options. Aztreonam-avibactam (ATM-AVI), which is under clinical development, has shown activity against MBL-positive isolates. This study evaluated the prevalence of MBL producers and the nature of enzymes among a global collection of clinical isolates of Enterobacterales from the Antimicrobial Testing Leadership and Surveillance program (ATLAS) surveillance program (2016-2020), and the antimicrobial activity of ATM-AVI and comparators against this collection.

METHODS

Non-duplicate clinical isolates of Enterobacterales (N = 106 686) collected across 63 countries were analysed. Antimicrobial susceptibility was performed using broth microdilution. Minimum inhibitory concentrations (MICs) were interpreted using Clinical and Laboratory Standards Institute and European Committee on Antimicrobial Susceptibility Testing breakpoints. Provisional pharmacokinetic/pharmacodynamic breakpoint of ≤8 mg/L was considered for ATM-AVI. β-lactamase genes were characterized by polymerase chain reaction and sequencing. The Cochran Armitage Trend test was used to determine significant trends in percentage of isolates over time.

RESULTS

Overall, MBL-positive isolates were 1.6% of total Enterobacterales isolates globally, with a significant increasing trend observed over time, globally and across regions (P < 0.05). New Delhi MBL (NDM) was the most common MBL (83.3%). ATM-AVI demonstrated potent activity against MBL-positive isolates (MIC ≤8 mg/L: 99.4% isolates inhibited; MIC90, 1 mg/L). Consistent activity was also noted across different regions. Potent activity was demonstrated against different NDM variants and MBL-positive isolates co-carrying other carbapenemases (98.1% and 99.7% isolates inhibited at ≤8 mg/L, respectively). About 0.6% MBL-positive isolates (10/1707) had MICs >8 mg/L for ATM-AVI.

CONCLUSION

ATM-AVI demonstrated potent activity against MBL-positive isolates, including NDM variants and MBL-positive isolates co-carrying other carbapenemases, and may represent a good option for treating infections caused by MBL-positive Enterobacterales.

Bloodstream infections after solid organ transplantation: clinical epidemiology and antimicrobial resistance (2016-21)

Background

Solid organ transplant (SOT) recipients are at risk of bloodstream infections (BSIs) with MDR organisms (MDROs).

Objectives

To describe the epidemiology of BSI in the year after several types of SOT, as well as the prevalence of MDRO infections in this population.

Methods

We conducted a single-centre, retrospective study of kidney, liver, heart, and multi-organ transplantation patients. We examined BSIs ≤1 year from SOT and classified MDRO phenotypes for Staphylococcus aureus, enterococci, Enterobacterales, Pseudomonas aeruginosa and Candida spp. We compared BSI characteristics between SOT types and determined risk factors for 90 day mortality.

Results

We included 2293 patients [1251 (54.6%) kidney, 663 (28.9%) liver, 219 (9.6%) heart and 160 (7.0%) multi-organ transplant]. Overall, 8.5% of patients developed a BSI. BSIs were most common after multi-organ (23.1%) and liver (11.3%) transplantation (P < 0.001). Among 196 patients with BSI, 323 unique isolates were recovered, 147 (45.5%) of which were MDROs. MDROs were most common after liver transplant (53.4%). The most frequent MDROs were VRE (69.8% of enterococci) and ESBL-producing and carbapenem-resistant Enterobacterales (29.2% and 27.2% of Enterobacterales, respectively). Mortality after BSI was 9.7%; VRE was independently associated with mortality (adjusted OR 6.0, 95% CI 1.7-21.3).

Conclusions

BSI incidence after SOT was 8.5%, with a high proportion of MDROs (45.5%), especially after liver transplantation. These data, in conjunction with local antimicrobial resistance patterns and prescribing practices, may help guide empirical antimicrobial selection and stewardship practices after SOT.

Clinical, microbiological and genomic characterization of Gram-negative bacteria with dual carbapenemases as identified by rapid molecular testing

Objective

Dual carbapenemase-producing organisms (DCPOs) are an emerging threat that expands the spectrum of antimicrobial resistance. There is limited literature on the clinical and genetic epidemiology of DCPOs.

Methods

DCPO isolates were identified by Xpert® Carba-R PCR testing of routine diagnostic cultures performed from 2018 to 2021 at a New York City health system. WGS was performed by Illumina and/or PacBio. Medical records of patients were reviewed for clinical and epidemiological data.

Results

Twenty-six DCPO isolates were obtained from 13 patients. Klebsiella pneumoniae (n = 22) was most frequent, followed by Pseudomonas aeruginosa (n = 2), Escherichia coli (n = 1) and Enterobacter cloacae (n = 1). The most common DCPO combination was blaNDM/blaOXA-48-like (n = 16). Notably, 1.05% (24/2290) of carbapenem-resistant Enterobacterales isolates were identified as DCPOs. The susceptibility profiles matched the identified resistance genes, except for a K. pneumoniae (blaKPC/blaOXA-48-like) isolate that was phenotypically susceptible to meropenem. Eleven patients were hospitalized within the year prior to admission, and received antibiotic(s) 1 month prior. Seven patients were originally from outside the USA. Hypertension, kidney disease and diabetes were frequent comorbidities. Death in two cases was attributed to DCPO infection. WGS of eight isolates showed that carbapenemases were located on distinct plasmids, except for one K. pneumoniae isolate where NDM and KPC carbapenemases were located on a single IncC-type plasmid backbone.

Conclusions

Here we characterized a series of DCPOs from New York City. Foreign travel, prior hospitalization, antibiotic usage and comorbidities were common among DCPO cases. All carbapenemases were encoded on plasmids, which may facilitate horizontal transfer.

Antibiotics in anesthesia and critical care

Sepsis is life-threatening organ dysfunction due to a dysregulated host response to an underlying acute infection. Sepsis is a major worldwide healthcare problem. An annual estimated 48.9 million incident cases of sepsis is reported, with 11 million (20%) sepsis-related deaths. Administration of appropriate antimicrobials is one of the most effective therapeutic interventions to reduce mortality. The severity of illness informs the urgency of antimicrobial administration. Nevertheless, even used properly, they cause adverse effects and contribute to the development of antibiotic resistance. Both inadequate and unnecessarily broad empiric antibiotics are associated with higher mortality and also select for antibiotic-resistant germs. In this narrative review, we will first discuss important factors and potential confounders which may influence the occurrence of surgical site infection (SSI) and which should be considered in the provision of perioperative antibiotic prophylaxis (PAP). Then, we will summarize recent advances and perspectives to optimize antibiotic therapy in the intensive care unit (ICU). Finally, the major role of the microbiota and the impact of antimicrobials on it will be discussed. While expert recommendations help guide daily practice in the operating theatre and ICU, a thorough knowledge of pharmacokinetic/pharmacodynamic (PK/PD) rules is critical to optimize the management of complex patients and minimize the emergence of multidrug-resistant organisms.

Incidence of acute kidney injury (AKI) and its impact on patient outcomes among adult hospitalized patients with carbapenem-resistant Gram-negative infections who received targeted treatment with a newer β-lactam or β-lactam/β-lactamase inhibitor-, polymyxin- or aminoglycoside-containing regimen

BACKGROUND

Limited comparative data exist on acute kidney injury (AKI) risk and AKI-associated outcomes in hospitalized patients with carbapenem-resistant Gram-negative infections (CR-GNIs) treated with a newer β-lactam/β-lactam-β-lactamase inhibitor (BL/BL-BLI)-, polymyxin (PB)- or aminoglycoside (AG)-containing regimen. This study quantified the risk of AKI and AKI-related outcomes among patients with CR-GNIs treated with a newer BL/BL-BLI-, PB- or AG-containing regimen.

METHODS

A multicentre, retrospective, observational study was performed (2016-20). The study included adult hospitalized patients with (i) baseline estimated glomerular filtration rates ≥30 mL/min/1.73 m2; (ii) CR-GN pneumonia, complicated urinary tract infection or bloodstream infection; and (iii) receipt of newer BL/BL-BLI, PG or AG within 7 days of index CR-GN culture for ≥3 days. Outcomes included AKI, in-hospital mortality and hospital costs.

RESULTS

The study included 750 patients and most (48%) received a newer BL/BL-BLI. The median (IQR) treatment duration was 8 (5-11), 5 (4-8) and 7 (4-8) days in the newer BL/BL-BLI group, AG group and PB group, respectively. The PB group had the highest adjusted AKI incidence (95% CI) (PB: 25.1% (15.6%-34.6%) versus AG: 8.9% (5.7%-12.2%) versus newer BL/BL-BLI: 11.9% (8.1%-15.7%); P = 0.001). Patients with AKI had significantly higher in-hospital mortality (AKI: 18.5% versus 'No AKI': 5.6%; P = 0.001) and mean hospital costs (AKI: $49 192 versus 'No AKI': $38,763; P = 0.043).

CONCLUSIONS

The AKI incidence was highest among PB patients and patients with AKI had worse outcomes. Healthcare systems should consider minimizing the use of antibiotics that augment AKI risk as a measure to improve outcomes in patients with CR-GNIs.

Long-term intensive care unit outbreak of carbapenemase-producing organisms associated with contaminated sink drains

BACKGROUND

Between 2018 and 2022, a Belgian tertiary care hospital faced a growing issue with acquiring carbapenemase-producing organisms (CPO), mainly VIM-producing P. aeruginosa (PA-VIM) and NDM-producing Enterobacterales (CPE-NDM) among hospitalized patients in the adult intensive care unit (ICU).

AIM

To investigate this ICU long-term CPO outbreak involving multiple species and a persistent environmental reservoir.

METHODS

Active case finding, environmental sampling, whole-genome sequencing (WGS) analysis of patient and environmental strains, and implemented control strategies were described in this study.

FINDINGS

From 2018 to 2022, 37 patients became colonized or infected with PA-VIM and/or CPE-NDM during their ICU stay. WGS confirmed the epidemiological link between clinical and environmental strains collected from the sink drains with clonal strain dissemination and horizontal gene transfer mediated by plasmid conjugation and/or transposon jumps. Environmental disinfection by quaternary ammonium-based disinfectant and replacement of contaminated equipment failed to eradicate environmental sources. Interestingly, efflux pump genes conferring resistance to quaternary ammonium compounds were widespread in the isolates. As removing sinks was not feasible, a combination of a foaming product degrading the biofilm and foaming disinfectant based on peracetic acid and hydrogen peroxide has been evaluated and has so far prevented recolonization of the proximal sink drain by CPO.

CONCLUSION

The persistence in the hospital environment of antibiotic- and disinfectant-resistant bacteria with the ability to transfer mobile genetic elements poses a serious threat to ICU patients with a risk of shifting towards an endemicity scenario. Innovative strategies are needed to address persistent environmental reservoirs and prevent CPO transmission.

Production of OXA-48 carbapenemase acts as an independent risk factor for poor outcome in Klebsiella pneumoniae infection

PURPOSE

To know whether the production of OXA-48 carbapenemase exerts an independent impact on the outcome of Klebsiella pneumoniae infection, once adjusted by clinical syndrome and baseline risk factors.

METHODS

We performed a case-cohort study including 117 infectious episodes due to OXA-48-producing K. pneumoniae (OXA-48-Kp) and 117 episodes due to non-OXA-48-producing strains (non-OXA-48-Kp). Both groups were matched (1:1 ratio) by clinical syndrome (source of infection, preceding invasive procedures and indwelling devices, and associated bacteremia) and hospitalization ward at infection onset. Multivariate Cox regression was used to investigate the association between OXA-48-Kp infection and clinical cure by day 14 (primary outcome) and 30-day all-cause mortality (secondary outcome).

RESULTS

Both study groups were well balanced regarding underlying conditions and comorbidity burden. Sepsis or septic shock were more frequent in OXA-48-Kp cases than non-OXA-48-Kp controls (41 [35.0%] vs. 17 [14.5%]; P-value < 0.0001). Clinical cure by day 14 was less commonly achieved in OXA-48-Kp cases (49 [41.9%] vs. 95 [81.2%]; P-value < 0.001), whereas 30-day all-cause mortality was higher (33 [28.2%] vs. 18 [15.4%]; P-value = 0.018). Multivariate analysis confirmed that OXA-48-Kp infection was independently associated with the lack of 14-day clinical cure (adjusted hazard ratio [aHR]: 0.45; 95% confidential interval [95%CI]: 0.29-0.70; P-value < 0.0001). A non-significant association was observed for 30-day all-cause mortality (aHR: 1.65; 95%CI: 0.92-2.94; P-value = 0.093).

CONCLUSION

Our matched analysis suggests that the production of OXA-48 carbapenemase acts as an independent risk factor for poor outcome in K. pneumoniae infection as compared to episodes due to non-carbapenemase-producing strains.

Risk factors of carbapenemase-producing Enterobacterales acquisition among adult intensive care unit patients at a Kentucky Academic Medical Center

Background

Acquisition of carbapenemase-producing carbapenem-resistant Enterobacterales (CP-CRE) are associated with negative health outcomes. Our adult intensive care unit (ICU) population has experienced low levels of CP-CRE acquisition; however, specific risk factors for this population at our medical facility have not been studied.

Aims

To identify risk factors of CP-CRE acquisition and describe CP-CRE epidemiology among adult ICU patients at our medical facility.

Methods

A retrospective cohort study was performed at a Kentucky Academic Medical Center. Surveillance specimens were collected at admission and weekly thereafter to identify CP-CRE colonization. Clinical data were extracted from patient medical records. Cases were defined as those who tested positive for CP-CRE on ICU admission day 3 or greater. Risk of CP-CRE acquisition was calculated using Modified Poisson regression.

Findings

Independent risk factors of CP-CRE acquisition included administration of enteral tube feeds (risk ratio [RR], 4.46; 95% confidence interval [CI], 1.74-11.43); diagnosis of Clostridioides difficile enterocolitis (RR, 3.51; 95% CI, 1.27-9.68), pressure ulcer (RR, 3.48; 95% CI, 1.91-6.36), and morbid obesity (RR, 2.10; 95% CI, 1.12-3.95); having a drainage tube (RR, 2.63; 95% CI, 1.38-4.98); admission to a medical ICU (RR, 2.39; 95% CI, 1.32-4.35); 90-day use of a carbapenem (RR, 2.27; 95% CI, 1.21-4.26); and dialysis procedure (RR, 2.22; 95% CI, 1.15-4.27).

Conclusion

Most CP-CRE risk factors were associated with alteration of colon microbiota and/or invasive procedures/devices. These results will assist in creating a more targeted CP-CRE active surveillance system and highlight areas for infection prevention intervention.

Clinical and Molecular Characteristics of Carbapenemase-Producing E. coli Strains from Patients with Biliary System Diseases and Hematological Malignancies

Purpose

This study aims to investigate the clinical and molecular characteristics of carbapenemase-producing E. coli strains (CPECO).

Patients and Methods

We collected 38 non-repetitive CPECO strains, identified them using MALDI-TOF, and assessed their antimicrobial susceptibility via the VITEK-Compact II system. We gathered demographic and clinical patient data. Phenotypic assays were employed to detect carbapenemase types. Polymerase chain reaction (PCR) was utilized to identify the carbapenemase genes. Seven housekeeping genes were amplified and sequenced to determine the multilocus sequence typings (MLSTs).

Results

These CPECO strains, primarily isolated from aseptic site and stool screening specimens, exhibited significant resistance to most clinical antibiotics, except for tigecycline and amikacin. Most patients had underlying medical conditions and underwent invasive procedures. There were significant differences among patients concerning the presence of malignancies, digestive system disorders, endoscopic retrograde cholangiopancreatography (ERCP) surgeries and abdominal drainage tubes. However, no significant differences were observed among patients regarding conditions, including hypertension, diabetes, respiratory diseases, urinary diseases and cardiovascular diseases, as well as invasive procedures such as deep venous catheterization, endotracheal intubation and gastrointestinal catheterization. Metallo-β-lactamase was primarily responsible for carbapenem resistance, including blaNDM-5(24/38), blaNDM-1(5/38), blaNDM-9(1/38) and blaIMP-4(1/38). Additionally, 7 CPECO strains carried blaKPC-2. The distribution of CPECO sequence types (STs) was diverse, with seven strains being ST131, six strains being ST410, three strains each of ST1196 and ST10, although most STs were represented by only one strain.

Conclusion

CPECO infections in patients with biliary system diseases may result from intestinal CPECO translocation, with ERCP surgery potentially facilitating this. Meanwhile, malignant tumor was found to be a significant factor affecting CPECO infections in patients with hematological diseases. blaNDM-5, blaNDM-1 and blaNDM-9 were primarily responsible for carbapenem resistance in CPECO strains. The emergence of carbapenem-resistant ST131 and ST410 strains should be alert to prevent the spread of carbapenem-resistant genes within high-risk epidemic clones.

Antimicrobial Activities of Aztreonam-Avibactam and Comparator Agents against Enterobacterales Analyzed by ICU and Non-ICU Wards, Infection Sources, and Geographic Regions: ATLAS Program 2016-2020

Increasing antimicrobial resistance among multidrug-resistant (MDR), extended-spectrum β-lactamase (ESBL)- and carbapenemase-producing Enterobacterales (CPE), in particular metallo-β-lactamase (MBL)-positive strains, has led to limited treatment options in these isolates. This study evaluated the activity of aztreonam-avibactam (ATM-AVI) and comparator antimicrobials against Enterobacterales isolates and key resistance phenotypes stratified by wards, infection sources and geographic regions as part of the ATLAS program between 2016 and 2020. Minimum inhibitory concentrations (MICs) were determined per Clinical and Laboratory Standards Institute (CLSI) guidelines. The susceptibility of antimicrobials were interpreted using CLSI and European Committee on Antimicrobial Susceptibility Testing (EUCAST) breakpoints. A tentative pharmacokinetic/pharmacodynamic breakpoint of 8 µg/mL was considered for ATM-AVI activity. ATM-AVI inhibited ≥99.2% of Enterobacterales isolates across wards and ≥99.7% isolates across infection sources globally and in all regions at ≤8 µg/mL. For resistance phenotypes, ATM-AVI demonstrated sustained activity across wards and infection sources by inhibiting ≥98.5% and ≥99.1% of multidrug-resistant (MDR) isolates, ≥98.6% and ≥99.1% of ESBL-positive isolates, ≥96.8% and ≥90.9% of carbapenem-resistant (CR) isolates, and ≥96.8% and ≥97.4% of MBL-positive isolates, respectively, at ≤8 µg/mL globally and across regions. Overall, our study demonstrated that ATM-AVI represents an important therapeutic option for infections caused by Enterobacterales, including key resistance phenotypes across different wards and infection sources.

The Efficacy and Safety of Intravenous Colistin Plus Aerosolized Colistin Versus Intravenous Colistin Alone in Critically Ill Trauma Patients With Multi-Drug Resistant Gram-Negative Bacilli Infection

BACKGROUND AND AIM

Gram-negative bacteria (GNB) with potential multiple drug resistance (MDR) have emerged as a major group of organisms causing ventilator-associated pneumonia (VAP). Higher concentrations are deposited directly in the lungs when antibiotics are given via inhalation, minimizing systemic side effects. This study aims to compare the efficacy and safety of intravenous plus aerosolized colistin versus intravenous (IV) colistin alone in critically ill trauma patients who reported MDR-GNB infection on endotracheal aspirate culture.

METHODS

A hundred patients were recruited in the Intensive Care Unit, Trauma Centre, Institute of Medical Sciences, Banaras Hindu University, Varanasi, and randomly assigned to the control (n=50) group, which received IV colistin plus aerosolized colistin and the intervention group (n = 50), which received IV colistin alone. Changes in total leucocyte count (TLC), renal function test (RFT), endotracheal aspirate culture, 24-hour urine output, length of ICU stay, and 28-day ICU mortality were investigated.

RESULTS

Patients receiving intravenous plus nebulized colistin therapy had a better outcome compared to IV colistin alone in terms of faster eradication of MDR-GNB infection. A rise in serum urea and creatinine levels was seen in both groups, which were significantly higher, along with a decrease in urine output in the group receiving intravenous colistin alone. No significant difference was observed in serum sodium and potassium levels in the RFT protocol, length of ICU stay, or 28-day ICU mortality.

CONCLUSION

Intravenous nebulized colistin could be considered a better alternative therapy for VAP caused by multi-drug-resistant Gram-negative bacteria in the ICU in terms of faster microbiological cure and lesser nephrotoxicity.

Multidrug-Resistant and Extensively Drug-Resistant Escherichia coli in Sewage in Kuwait: Their Implications

In Kuwait, some sewage is discharged into the sea untreated, causing a health risk. Previously, we investigated the presence of pathogenic E. coli among the 140 isolates of E. coli cultured from the raw sewage from three sites in Kuwait. The aim of the current study was to characterize the antimicrobial resistance of these isolates and the implications of resistance. Susceptibility to 15 antibiotic classes was tested. Selected genes mediating resistance to cephalosporins and carbapenems were sought. ESBL and carbapenemase production were also determined. Two virulent global clones, ST131 and ST648, were sought. A total of 136 (97.1%), 14 (10.0%), 128 (91.4%), and 2 (1.4%) isolates were cephalosporin-resistant, carbapenem-resistant, multidrug-resistant (MDR), and extensively drug-resistant (XDR), respectively. Among the cephalosporin-resistant isolates, ampC, blaTEM, blaCTX-M, blaOXA-1, and blaCMY-2 were found. Eighteen (12.9%) samples were ESBL producers. All carbapenem-resistant isolates were negative for carbapenemase genes (blaOXA-48, blaIMP, blaGES, blaVIM, blaNDM, and blaKPC), and for carbapenemase production. Resistance rates in carbapenem-resistant isolates to many other antibiotics were significantly higher than in susceptible isolates. A total of four ST131 and ST648 isolates were detected. The presence of MDR and XDR E. coli and global clones in sewage poses a threat in treating E. coli infections.

Efficacy and Safety of Cefmetazole for Bacteremia Caused by Extended-Spectrum β-Lactamase-Producing Enterobacterales vs Carbapenems: A Retrospective Study

Background

Extended-spectrum β-lactamase (ESBL)-producing Enterobacterales have become a global concern owing to increased infections, high mortality, and limited antibiotic treatment options. Carbapenems (CPMs) are effective against ESBL-producing Enterobacterales, but their overuse leads to the emergence of multidrug-resistant bacteria. Cefmetazole (CMZ) is effective in vitro; however, its clinical efficacy remains unclear.

Methods

We retrospectively reviewed patients who were treated with CMZ or CPMs for bacteremia caused by ESBL-producing Enterobacterales between 1 April 2014 and 31 September 2022 at Tenri Hospital. The primary outcome measure was 90-day mortality. We also evaluated resistance genes and sequence types of ESBL-producing Enterobacterales.

Results

In total, 156 patients were enrolled in this study. Ninety patients (58%) received CMZ therapy. Patients in the CMZ group were significantly older than those in the CPM group (median [IQR], 79 years [71-86] vs 74 years [64-83]; P = .001). The severity of the Pitt bacteremia score of the CMZ group was lower than that in the CPM group (0 [0-2] vs 2 [0-2], P = .042). Six patients (7%) in the CMZ group and 10 (15%) in the CPM group died by day 90 (P = .110). Charlson Comorbidity Index and prevalence of sequence 131 between the groups were statistically insignificant.

Conclusions

Our findings suggest that CMZ is a well-tolerated alternative to CPM for treating bacteremia caused by ESBL-producing Enterobacterales.

Comparative De Novo and Pan-Genome Analysis of MDR Nosocomial Bacteria Isolated from Hospitals in Jeddah, Saudi Arabia

Multidrug-resistant (MDR) bacteria are one of the most serious threats to public health, and one of the most important types of MDR bacteria are those that are acquired in a hospital, known as nosocomial. This study aimed to isolate and identify MDR bacteria from selected hospitals in Jeddah and analyze their antibiotic-resistant genes. Bacteria were collected from different sources and wards of hospitals in Jeddah City. Phoenix BD was used to identify the strains and perform susceptibility testing. Identification of selected isolates showing MDR to more than three classes on antibiotics was based on 16S rRNA gene and whole genome sequencing. Genes conferring resistance were characterized using de novo and pan-genome analyses. In total, we isolated 108 bacterial strains, of which 75 (69.44%) were found to be MDR. Taxonomic identification revealed that 24 (32%) isolates were identified as Escherichia coli, 19 (25.3%) corresponded to Klebsiella pneumoniae, and 17 (22.67%) were methicillin-resistant Staphylococcus aureus (MRSA). Among the Gram-negative bacteria, K. pneumoniae isolates showed the highest resistance levels to most antibiotics. Of the Gram-positive bacteria, S. aureus (MRSA) strains were noticed to exhibit the uppermost degree of resistance to the tested antibiotics, which is higher than that observed for K. pneumoniae isolates. Taken together, our results illustrated that MDR Gram-negative bacteria are the most common cause of nosocomial infections, while MDR Gram-positive bacteria are characterized by a wider antibiotic resistance spectrum. Whole genome sequencing found the appearance of antibiotic resistance genes, including SHV, OXA, CTX-M, TEM-1, NDM-1, VIM-1, ere(A), ermA, ermB, ermC, msrA, qacA, qacB, and qacC.

Cefepime in vivo activity against carbapenem-resistant Enterobacterales that test as cefepime susceptible or susceptible-dose dependent in vitro: implications for clinical microbiology laboratory and clinicians

BACKGROUND

Carbapenem-resistant Enterobacterales (CRE) are a public health concern. Among these isolates, there are reports of isolates that test as cefepime susceptible or susceptible-dose dependent (SDD) in vitro despite presence of a carbapenemase. This study aimed to evaluate the pharmacokinetic/pharmacodynamic profile of cefepime against carbapenemase-producing (CP-CRE) and non-producing (non-CP-CRE) isolates with a range of cefepime MICs.

METHODS

Reference broth microdilution and modified carbapenem inactivation method (mCIM) were performed on genotypically characterized clinical CRE isolates. Ultimately, CP-CRE (n = 21; blaKPC) and non-CP-CRE (n = 19) isolates with a distribution of cefepime MICs (≤0.5 to >256 mg/L) were utilized in the murine thigh infection model. Mice were treated with cefepime human-simulated regimens (HSRs) representative of a standard dose (1 g q12h 0.5 h infusion) or the SDD dose (2 g q8h 0.5 h infusion). Efficacy was assessed as the change in bacterial growth at 24 h compared with 0 h control, where ≥1 log bacterial reduction is considered translational value for clinical efficacy.

RESULTS

Among both cohorts of CRE isolates, i.e. CP-CRE and non-CP-CRE, that tested as SDD to cefepime in vitro, 1 log bacterial reduction was not attainable with cefepime. Further blunting of cefepime efficacy was observed among CP-CRE isolates compared with non-CP-CRE across both susceptible and SDD categories.

CONCLUSIONS

Data indicate to avoid cefepime for the treatment of serious infections caused by CRE isolates that test as cefepime susceptible or SDD. Data also provide evidence that isolates with the same antibiotic MIC may have different pharmacokinetic/pharmacodynamic profiles due to their antimicrobial resistance mechanism.

Efficacy of ceftazidime-avibactam, meropenem-vaborbactam, and imipenem-relebactam combinations against carbapenemase-producing Enterobacterales in Switzerland

Carbapenemase-producing in Enterobacterales (CPE) represent a critical health concern worldwide, including in Switzerland, leading to very limited therapeutic options. Therefore, our aim was to evaluate the susceptibility to the novel ß-lactam/ß-lactamase inhibitor combinations ceftazidime-avibactam, meropenem-vaborbactam, and imipenem-relebactam of CPE isolates recovered in Switzerland from 2018 to 2020. A total of 150 clinical CPE were studied including mainly Klebsiella pneumoniae (n = 61, 40.3%) and Escherichia coli (n = 53, 35.3%). The distribution of carbapenemases was as follows: KPC-like (32%), OXA-48-like (32%), NDM-like (24%), combinations of carbapenemases (10%), VIM-1 producers (n = 2), and a single IMI-1 producer. Overall, 77% of the strains were susceptible to meropenem-vaborbactam, 63% was susceptible to ceftazidime-avibactam, and 62% susceptible to imipenem-relebactam. Those data may contribute to optimize the choice of first line therapy for treating infections due to CPE.

Prevalence and Outcomes of Carbapenem-resistant Bloodstream Infection in Children With Cancer

INTRODUCTION

Carbapenem-resistant (CR) infections cause major morbidity and mortality. Data on CR infections in children with cancer are scarce, especially from the developing world. The aim of this study was to evaluate the characteristics and outcomes of bacteremia with CR organisms (CRO) compared with bacteremia with Carbapenem-sensitive organisms in children with cancer.

METHODS

This retrospective observational study was conducted in a tertiary pediatric oncology center in South India. Data on all bloodstream infections with Gram-negative organisms (CRO and Carbapenem sensitive-organisms) in children with malignancy ≤14 years of age from August 2017 to July 2021 were retrieved. The outcome was determined as survival and all-cause death 28 days after the date of Bloodstream infection (BSI) onset.

RESULTS

Sixty-four Gram-negative BSI were identified, with 24% (n=15) in the Carbapenem-Resistant Bloodstream Infection (CR-BSI) group and 76% (n=49) in the Carbapenem-sensitive-Bloodstream Infection group. The patients included 35 males (64%) and 20 females (36%), with ages ranging from 1 year to 14 years (median age: 6.2 y). The most common underlying disease was hematologic malignancy (92.2%, n=59). Children with CR-BSI had a higher incidence of prolonged neutropenia, septic shock, pneumoniae, enterocolitis, altered consciousness, and acute renal failure and were associated with 28-day mortality in univariate analysis. The most common carbapenem-resistant Gram-negative bacilli isolates were Klebsiella species (47%) and Escherichia coli (33%). All carbapenem-resistant isolates were sensitive to colistin, and 33% were sensitive to Tigecycline. The case-fatality rate was 14% (9/64) in our cohort. The overall 28 days mortality was significantly higher in patients with CR-BSI than in those with Carbapenem-sensitive Bloodstream Infection (28-day mortality: 43.8% vs. 4.2%, P =0.001).

CONCLUSIONS

Bacteremia with CRO has higher mortality in children with cancer. Prolonged neutropenia, pneumoniae, septic shock, enterocolitis, acute renal failure, and altered consciousness were predictors of 28-day mortality in carbapenem-resistant septicemia.

Mortality Attributable to Bloodstream Infections Caused by Different Carbapenem-Resistant Gram-Negative Bacilli: Results From a Nationwide Study in Italy (ALARICO Network)

BACKGROUND

Our aim was to analyze mortality attributable to carbapenem-resistant (CR) gram-negative bacilli (GNB) in patients with bloodstream infections (BSIs).

METHODS

Prospective multicentric study including patients with GNB-BSI from 19 Italian hospitals (June 2018-January 2020). Patients were followed-up to 30 days. Primary outcomes were 30-day mortality and attributable mortality. Attributable mortality was calculated in the following groups: Klebsiella pneumoniae carbapenemase (KPC)-producing Enterobacterales, metallo-β-lactamases (MBL)-producing Enterobacterales, CR-Pseudomonas aeruginosa (CRPA), CR-Acinetobacter baumannii (CRAB). A multivariable analysis with hospital fixed-effect was built to identify factors associated with 30-day mortality. Adjusted OR (aORs) were reported. Attributable mortality was calculated according to the DRIVE-AB Consortium.

RESULTS

Overall, 1276 patients with monomicrobial GNB BSI were included: 723/1276 (56.7%) carbapenem-susceptible (CS)-GNB, 304/1276 (23.8%) KPC-, 77/1276 (6%) MBL-producing CRE, 61/1276 (4.8%) CRPA, and 111/1276 (8.7%) CRAB BSI. Thirty-day mortality in patients with CS-GNB BSI was 13.7% compared to 26.6%, 36.4%, 32.8% and 43.2% in patients with BSI by KPC-CRE, MBL-CRE, CRPA and CRAB, respectively (P < .001). On multivariable analysis, age, ward of hospitalization, SOFA score, and Charlson Index were factors associated with 30-day mortality, while urinary source of infection and early appropriate therapy resulted protective factors. Compared to CS-GNB, MBL-producing CRE (aOR 5.86, 95% CI 2.72-12.76), CRPA (aOR 1.99, 95% CI 1.48-5.95) and CRAB (aOR 2.65, 95% CI 1.52-4.61) were significantly associated with 30-day mortality. Attributable mortality rates were 5% for KPC-, 35% for MBL, 19% for CRPA, and 16% for CRAB.

CONCLUSIONS

In patients with BSIs, carbapenem-resistance is associated with an excess of mortality, with MBL-producing CRE carrying the highest risk of death.

Updates on the Status of Carbapenem-Resistant Enterobacterales in Lebanon

Carbapenem-resistant Enterobacterales (CRE) pathogens have been increasingly isolated and reported in Lebanon. Several studies have been published over the last two decades about the CRE situation in the country. However, compared to the worldwide data, those studies are scarce and mostly restricted to single center studies. In this review, we aim to present a comprehensive and reliable report illustrating the current situation regarding CRE in Lebanon. Variable studies have shown an increasing pattern of carbapenem resistance in Enterobacterales since the first reports of CRE isolates in 2007 and 2008. Escherichia coli and Klebsiella pneumoniae were the most detected ones. The OXA-48 class D carbapenemases were the most prevalent carbapenemases among CRE isolates. Moreover, the emergence of other carbapenemases like the NDM class B carbapenemase has been noticed. Strict infection control measures in hospitals, including the identification of CRE carriers, are needed in Lebanese hospitals since carriage is a potential risk for the spread of CRE in healthcare settings. The dissemination of CRE in the community is noticed and attributed to multiple causes, such as the refugee crisis, water contamination, and antimicrobial misuse. In conclusion, strict infection control measures in healthcare settings, in addition to accurate antimicrobial stewardship program implementation, are urgently needed.

Clinical Characteristics and Associated Factors for Mortality in Patients with Carbapenem-Resistant Enterobacteriaceae Bloodstream Infection

BACKGROUND

Bloodstream infection (BSI) caused by carbapenem-resistant Enterobacteriaceae (CRE) significantly influences patient morbidity and mortality. We aimed to identify the characteristics, outcomes, and risk factors of mortality in adult patients with CRE bacteremia and elucidate the differences between carbapenemase-producing (CP)-CRE BSI and non-CP-CRE BSI.

METHODS

This retrospective study included 147 patients who developed CRE BSI between January 2016 and January 2019 at a large tertiary care hospital in South Korea. The patient demographic characteristics and clinical and microbiological data including the Enterobacteriaceae species and carbapenemase type were obtained and analyzed.

RESULTS

Klebsiella pneumoniae was the most commonly detected pathogen (80.3%), followed by Escherichia coli (15.0%). In total, 128 (87.1%) isolates were found to express carbapenemase, and most CP-CRE isolates harbored bla_KPC. The 14-day and 30-day mortality rates for CRE BSI were 34.0% and 42.2%, respectively. Higher body mass index (odds ratio (OR), 1.123; 95% confidence interval (CI), 1.012-1.246; p = 0.029), higher sequential organ failure assessment (SOFA) score (OR, 1.206; 95% CI, 1.073-1.356; p = 0.002), and previous antibiotic use (OR, 0.163; 95% CI, 0.028-0.933; p = 0.042) were independent risk factors for the 14-day mortality. A high SOFA score (OR, 1.208; 95% CI; 1.081-0.349; p = 0.001) was the only independent risk factor for 30-day mortality. Carbapenemase production and appropriate antibiotic treatment were not associated with high 14- or 30-day mortality rates.

CONCLUSIONS

Mortality from CRE BSI was related to the severity of the infection rather than to carbapenemase production or antibiotic treatment, showing that efforts to prevent CRE acquisition rather than treatment following CRE BSI detection would be more effective at reducing mortality.

Gut microbiota alterations in critically Ill patients with carbapenem-resistant Enterobacteriaceae colonization: A clinical analysis

Background

Carbapenem-resistant Enterobacteriaceae (CRE) are an emerging concern for global health and are associated with high morbidity and mortality in critically ill patients. Risk factors for CRE acquisition include broad-spectrum antibiotic use and microbiota dysbiosis in critically ill patients. Therefore, we evaluated the alteration of the intestinal microbiota associated with CRE colonization in critically ill patients.

Methods

Fecal samples of 41 patients who were diagnosed with septic shock or respiratory failure were collected after their admission to the intensive care unit (ICU). The gut microbiota profile determined using 16S rRNA gene sequencing and quantitative measurement of fecal short-chain fatty acids were evaluated in CRE-positive (n = 9) and CRE negative (n = 32) patients. The analysis of bacterial metabolic abundance to identify an association between CRE acquisition and metabolic pathway was performed.

Results

CRE carriers showed a significantly increased proportion of the phyla Proteobacteria and decreased numbers of the phyla Bacteroidetes as compared to the CRE non-carriers. Linear discriminant analysis (LDA) with linear discriminant effect size showed that the genera Erwinia, Citrobacter, Klebsiella, Cronobacter, Kluyvera, Dysgomonas, Pantoea, and Alistipes had an upper 2 LDA score in CRE carriers. The alpha-diversity indices were significantly decreased in CRE carriers, and beta-diversity analysis demonstrated that the two groups were clustered significantly apart. Among short-chain fatty acids, the levels of isobutyric acid and valeric acid were significantly decreased in CRE carriers. Furthermore, the PICRUSt-predicted metabolic pathways revealed significant differences in five features, including ATP-binding cassette transporters, phosphotransferase systems, sphingolipid metabolism, other glycan degradation, and microbial metabolism, in diverse environments between the two groups.

Conclusion

Critically ill patients with CRE have a distinctive gut microbiota composition and community structure, altered short-chain fatty acid production and changes in the metabolic pathways. Further studies are needed to determine whether amino acids supplementation improves microbiota dysbiosis in patients with CRE.

Clinical Management of a Pandrug-Resistant OXA-48 Klebsiella pneumoniae Infection in the Pediatric Intensive Care Unit

Background: Carbapenem-resistant Klebsiella pneumoniae (CRKP) is one of the serious forms of health care-associated infection. Pan-drug resistant (PDR) CRKP infections can cause severe infections. Mortality and treatment costs in the pediatric intensive care unit (PICU) are high. This study aims to share our experience regarding the treatment of oxacillinase (OXA)-48-positive PDR-CRKP infection in our 20-bed tertiary PICU with isolated rooms and 1 nurse for every 2-3 patients. Methods: Patient demographic characteristics, underlying diseases, previous infections, source of infection PDR-CRKP, treatment modalities, measures used, and outcomes were recorded. Findings: Eleven patients (eight men and three women) were found to have PDR OXA-48-positive CRKP. Because of the simultaneous detection of PDR-CRKP in three patients and the rapid spread of the disease, it was classified as a clinical outbreak, and strict infection control measures were taken. Combination therapy with double carbapenemase (meropenem and imipenem), amikacin, colistin, and tigecycline was used for treatment. The mean duration of treatment and isolation was 15.7 and 65.4 days, respectively. No treatment-related complication was observed, only one patient died, and the mortality rate was 9%. Conclusions: This severe clinical outbreak can be successfully treated with effective treatment with combined antibiotics and strict adherence to infection control measures. ClinicalTrial.gov ID: 28/01/2022 - 1/5.

Efficacy and safety of ceftazidime-avibactam compared to other antimicrobials for the treatment of infections caused by carbapenem-resistant Klebsiella pneumoniae strains, a systematic review and meta-analysis

INTRODUCTION

Carbapenem-resistant Klebsiella pneumoniae (CRKP) infections are a significant public health issue. CRKP infections can increase the mortality of severely ill hospitalised patients and elevate the financial burden of their hospitalisation globally. Colistin and tigecycline are the main antimicrobials which have been widely used for the treatment of CRKP infections. However, novel antimicrobials have been recently launched. Ceftazidime-avibactam (CAZ-AVI) seems one of the most efficient ones.

AIM

The aim of the current systematic literature review and meta-analysis is to assess the efficacy and safety of CAZ-AVI compared to other antimicrobials in adult patients (aged >18) with CRKP infection.

METHODS

All data were retrieved using PubMed/Medline, the Web of Science and Cochrane library. The main outcome was the effective treatment of CRKP infection or the microbiological eradication of CRKP in the culture of biological samples. Secondary outcomes included the impact on 28- or 30-day mortality and adverse effects, if available. Pooled analysis was conducted using Review Manager v. 5.4.1 software (RevMan). The level of statistical significance was set at p < 0.05.

RESULTS

CAZ-AVI was proved more effective than other antimicrobials against CRKP infections and CRKP bloodstream infections (p < 0.00001 and p < 0.0001, respectively). Patients in the CAZ-AVI arm displayed statistically lower 28- and 30-day mortality rates (p = 0.002 and p < 0.00001, respectively). Concerning the microbiological eradication, no meta-analysis was feasible due to high heterogeneity.

CONCLUSION

The promotion of CAZ-AVI for treating CRKP infections over other antimicrobials seems favourable. However, there is a long way ahead to reveal additional scientific findings to further strengthen this statement.

A single- and multiple-dose study to characterize the pharmacokinetics, safety, and tolerability of ceftolozane/tazobactam in healthy Chinese participants

Ceftolozane/tazobactam (C/T) is approved in several countries to treat complicated urinary tract infections, complicated intra-abdominal infections, and nosocomial pneumonia. There is a paucity of pharmacokinetics and safety data for C/T in Chinese participants. This study evaluated the pharmacokinetics, safety, and tolerability of C/T in 12 healthy Chinese participants after three single administrations of increasing doses (0.75 g, 1.5 g, and 3 g) and multiple administrations of 1.5 g C/T every 8 h for 3 days. After single doses, maximum concentrations of ceftolozane and tazobactam were reached by the end of the 1-h infusion and declined in a biphasic manner thereafter, with mean half-lives of 1.9-2.2 h and 0.74-0.95 h, respectively. Volume of distribution (V_d) and renal clearance (CL) were consistent across the three single-dose levels for ceftolozane (V_d, 15.8-19.5 L; CL, 5.68-6.09 L/h) and tazobactam (V_d, 23.3-28.6 L; CL, 20.8-23.5 L/h). Area under the concentration-time curve (AUC) extrapolated to infinity (ceftolozane, 88.1-328 h∙μg/mL; tazobactam, 10.7-48.0 h∙μg/mL) increased in a dose-dependent manner. After multiple doses over 3 days, AUC from time 0 to 8 h, and concentration at the end of infusion were similar to single-dose measurements (geometric mean ratios, 0.87-1.01 for both drugs). C/T was well tolerated, with no serious adverse events or discontinuations reported; all adverse events were mild. The pharmacokinetics and safety/tolerability of C/T in healthy Chinese participants was comparable to that in previous studies in other populations, supporting the use of C/T for the treatment of Chinese patients.

Proof-of-concept for incorporating mechanistic insights from multi-omics analyses of polymyxin B in combination with chloramphenicol against Klebsiella pneumoniae

Carbapenemase-resistant Klebsiella pneumoniae (KP) resistant to multiple antibiotic classes necessitates optimized combination therapy. Our objective is to build a workflow leveraging omics and bacterial count data to identify antibiotic mechanisms that can be used to design and optimize combination regimens. For pharmacodynamic (PD) analysis, previously published static time-kill studies (J Antimicrob Chemother 70, 2015, 2589) were used with polymyxin B (PMB) and chloramphenicol (CHL) mono and combination therapy against three KP clinical isolates over 24 h. A mechanism-based model (MBM) was developed using time-kill data in S-ADAPT describing PMB-CHL PD activity against each isolate. Previously published results of PMB (1 mg/L continuous infusion) and CHL (C_max : 8 mg/L; bolus q6h) mono and combination regimens were evaluated using an in vitro one-compartment dynamic infection model against a KP clinical isolate (10⁸ CFU/ml inoculum) over 24 h to obtain bacterial samples for multi-omics analyses. The differentially expressed genes and metabolites in these bacterial samples served as input to develop a partial least squares regression (PLSR) in R that links PD responses with the multi-omics responses via a multi-omics pathway analysis. PMB efficacy was increased when combined with CHL, and the MBM described the observed PD well for all strains. The PLSR consisted of 29 omics inputs and predicted MBM PD response (R²  = 0.946). Our analysis found that CHL downregulated metabolites and genes pertinent to lipid A, hence limiting the emergence of PMB resistance. Our workflow linked insights from analysis of multi-omics data with MBM to identify biological mechanisms explaining observed PD activity in combination therapy.

A Visualized Mortality Prediction Score Model in Hematological Malignancies Patients with Carbapenem-Resistant Organisms Bloodstream Infection

Background

Bloodstream infection (BSI) due to carbapenem-resistant organisms (CROs) has emerged as a worldwide problem associated with high mortality. This study aimed to evaluate the risk factors associated with mortality in HM patients with CROs BSI and to establish a scoring model for early mortality prediction.

Methods

We conducted a retrospective cohort study at our hematological department from January 2018 to December 2021, including all HM patients with CROs BSI. The outcome measured was death within 30-day of BSI onset. Survivor and non-survivor subgroups were compared to identify predictors of mortality. Univariate and multivariate Cox regression analyses were used to identify prognostic risk factors and develop a nomogram.

Results

In total, 150 HM patients were included in the study showing an overall 30-day mortality rate of 56%. Klebsiella pneumonia was the dominant episode. Cox regression analysis showed that pre-infection length of stay was >14 days (score 41), Pitt score >4 (score 100), mucositis (score 41), CAR (The ratio of C-reactive protein to albumin) >8.8 (score 57), early definitive therapy (score 44), and long-duration (score 78) were positive independent risk predictors associated with 30-day mortality, all of which were selected into the nomogram. Furthermore, all patients were divided into the high-risk group (≥160 points) or the low-risk group based on the prediction score model. The mortality of the high-risk group was 8 times more than the low-risk group. Kaplan-Meier analysis showed that empirical polymyxin B therapy was associated with a lower 30-day mortality rate, which was identified as a good prognostic factor in the high-risk group. In comparison, empirical carbapenems and tigecycline were poor prognostic factors in a low-risk group.

Conclusion

Our score model can accurately predict 30-day mortality in HM patients with CROs BSI. Early administration of CROs-targeted therapy in the high-risk group is strongly recommended to decrease mortality.

Evaluation of in-vitro colistin susceptibility and clinical profile of carbapenem resistant Enterobacteriaceae related invasive infections

PURPOSE

To determine the colistin susceptibility. To compare E-test vs broth-microdilution (BMD) method for invasive carbapenem resistant Enterobacteriaceae (CRE) infections. To study treatment options for the CRE. To analyze the clinical profile and outcome of CRE infections.

METHODS

Antimicrobial susceptibility testing was performed for 100 invasive CRE isolates. Gradient diffusion and BMD methods were performed to determine colistin MICs. Essential agreement (EA), categorical agreement (CA), very major error (VME), and major error (ME) were worked out between BMD method and E-test. The clinical profile of patients was analyzed.

RESULTS

The majority of the patients suffered from bacteremia [47(47%)]. Klebsiella pneumoniae was the most common organism isolated overall as well as among bacteremic isolates. 9(9%) CRE isolates were colistin resistant by BMD of which six were Klebsiella pneumoniae. There was 97% CA between E-test and BMD. EA was 68%. VME was found in three out of nine colistin resistant isolates. No ME was found. Among the other antibiotics tested for CRE isolates, the highest susceptibility was seen to tigecycline [43(43%)] followed by amikacin [19 (19%)]. The most common underlying condition was post solid organ transplantation [36(36%)]. A higher survival rate was seen among non-bacteremic CRE infections (58.49%) than bacteremic CRE infections (42.6%). Four out of nine patients with colistin resistant CRE infections survived and had a satisfactory outcome.

CONCLUSION

Klebsiella pneumoniae was the most common organism causing invasive infection. Survival rates were higher in non-bacteremic CRE infections than bacteremic infections. Good CA was seen between E-test and BMD for colistin susceptibility, but the EA was poor. VME was more common than ME when E-tests were used for colistin susceptibility testing resulting in false susceptibility. Tigecycline and aminoglycosides are possible adjunct drugs for the treatment of invasive CRE infections.

Efficacy of ceftazidime-avibactam in various combinations for the treatment of experimental osteomyelitis due to Klebsiella pneumoniae carbapenemase (KPC)-producing Klebsiella pneumoniae

BACKGROUND

Optimal treatment of carbapenemase-producing Enterobacterales (CPE) bone infections is poorly defined. This study evaluated the efficacy of the novel beta-lactam-beta-lactamase inhibitor-ceftazidime-avibactam (CAZ-AVI)-with different antibiotic combinations in an experimental model of CPE osteomyelitis.

METHODS

KPC-99YC is a clinical strain of Klebsiella pneumoniae carbapenemase (KPC)-producing Klebsiella pneumoniae with intermediate susceptibility to meropenem (MIC 4 mg/L), gentamicin (MIC 0.25 mg/L), colistin (MIC 0.25 mg/L), fosfomycin (MIC 4 mg/L) and ceftazidime-avibactam (MIC 1 mg/L). Time-kill curves were performed at 4x MIC. Osteomyelitis was induced in rabbits by tibial injection of 2×10⁸ CFU of KPC-99YC. Six groups started treatment 14 days later for 7 days: control, colistin, CAZ-AVI, CAZ-AVI plus gentamicin, CAZ-AVI plus colistin and CAZ-AVI plus fosfomycin. Antibiotic dosages were selected to simulate plasma concentrations obtained in humans. Treatment was evaluated according to bone cultures quantified in log₁₀ CFU.

RESULTS

In vitro, CAZ-AVI plus colistin or gentamicin were rapidly bactericidal in contrast with CAZ-AVI plus fosfomycin. In vivo, compared with controls, colistin alone (P = 0.045) and CAZ-AVI alone or in combination significantly lowered bone bacterial counts (P < 0.001). Bone sterilisation was achieved in 67% and 100% of animals with combinations of CAZ-AVI plus colistin or gentamicin (P = 0.001 and P < 0.001, respectively) whereas other treatments were no different from controls. CAZ-AVI plus gentamicin provided greater bone bacterial reduction than CAZ-AVI plus colistin (P = 0.033). No CAZ-AVI-resistant strains emerged in treated rabbits, regardless of combination.

CONCLUSIONS

CAZ-AVI plus gentamicin was the best effective combination therapy. Combinations with CAZ-AVI appear to be a promising treatment of KPC-producing Klebsiella pneumoniae osteomyelitis.

Tuning Peptide-Based Hydrogels: Co-Assembly with Composites Driving the Highway to Technological Applications

Self-assembled peptide-based gels provide several advantages for technological applications. Recently, the co-assembly of gelators has been a strategy to modulate and tune gel properties and even implement stimuli-responsiveness. However, it still comprises limitations regarding the required library of compounds and outcoming properties. Hence, efforts have been made to combine peptide-based gels and (in)organic composites (e.g., magnetic nanoparticles, metal nanoparticles, liposomes, graphene, silica, clay, titanium dioxide, cadmium sulfide) to endow stimuli-responsive materials and achieve suitable properties in several fields ranging from optoelectronics to biomedical. Herein, we discuss the recent developments with composite peptide-based gels including the fabrication, tunability of gels' properties, and challenges on (bio)technological applications.

Klebsiella Species and Enterobacter cloacae Isolates Harboring blaOXA-181 and blaOXA-48: Resistome, Fitness Cost, and Plasmid Stability

IncX3 and IncL plasmids have been named as catalysts advancing dissemination of blaOXA-181 and blaOXA-48 genes. However, their impact on the performance of host cells is vastly understudied. Genetic characteristics of blaOXA-48- and blaOXA-181-containing Klebsiella pneumoniae (EFN299), Klebsiella quasipneumoniae (EFN262), and Enterobacter cloacae (EFN743) isolated from clinical samples in a Ghanaian hospital were investigated by whole-genome sequencing. Transfer of plasmids by conjugation and electroporation, plasmid stability, fitness cost, and genetic context of blaOXA-48, blaOXA-181, and blaDHA-1 were assessed. blaOXA-181 was carried on two IncX3 plasmids, an intact 51.5-kb IncX3 plasmid (p262-OXA-181) and a 45.3-kb IncX3 plasmid (p743-OXA-181) without replication protein sequence. The fluoroquinolone-resistant gene qnrS1 region was also excised, and unlike in p262-OXA-181, the blaOXA-181 drug-resistant region was not found on a composite transposon. blaOXA-48 was carried on a 74.6-kb conjugative IncL plasmid with unknown ~10.9-kb sequence insertion. This IncL plasmid proved to be highly transferable, with a conjugation efficiency of 1.8 × 10-2. blaDHA-1 was present on an untypeable 22.2 kb genetic structure. Plasmid stability test revealed plasmid loss rate between 4.3% and 12.4%. The results also demonstrated that carriage of IncX3-blaOXA-181 or IncL-blaOXA-48 plasmids was not associated with any fitness defect, but rather an enhanced competitive ability of host cells. This study underscores the significant contribution of IncX3 and IncL plasmids in the dissemination of resistance genes and their efficient transfer calls for regular monitoring to control the expansion of resistant strains. IMPORTANCE The growing rate of antibiotic resistance is an important global health threat. This threat is exacerbated by the lack of safe and potent alternatives to carbapenems in addition to the slow developmental process of newer and effective antibiotics. Infections by carbapenem-resistant Gram-negative bacteria are becoming almost untreatable, leading to poor clinical outcomes and high mortality rates. OXA-48-like carbapenemases are one of the most widespread carbapenemases accounting for resistance among Enterobacteriaecae. We characterized OXA-48- and OXA-181-producing Enterobacteriaecae to gain insights into the genetic basis and mechanism of resistance to carbapenems. Findings from the study showed that the genes encoding these enzymes were carried on highly transmissible plasmids, one of which had sequences absent in other similar plasmids. This implies that mobile genetic elements are important players in the dissemination of resistance genes. Further characterization of this plasmid is warranted to determine the role of this sequence in the spread of resistance genes.

First Isolates of OXA-48-Like Carbapenemase-Producing Enterobacteriaceae in A Specialized Cancer Center

BACKGROUND

OXA-48-like carbapenemases have been found in a growing and varied number of carbapenemase-producing Enterobacteriaceae (CPE) isolates, and they are spreading to several countries. Although this oxacillinase leads to weak resistance to carbapenems without affecting broad-spectrum cephalosporin activity, when they are associated with other resistance mechanisms, the level of resistance to these antibiotics may be significantly higher. This weak resistance against carbapenems and cephalosporins, along with the absence of other resistance mechanisms, could render OXA-48-like harboring isolates undetected in the laboratory routine. In addition, the lack of a specific screening test for this enzyme complicates the detection of these isolates. This report characterizes the first isolates of OXA-48-like CPE detected in our laboratory.

MATERIALS AND METHODS

The study was carried out at the Instituto Nacional de Enfermedades Neoplasicas, Lima - Peru, between March and December 2021. OXA-48-like CPE isolates were detected as part of the routine microbiological study, and clinical data were obtained by reviewing medical records. The automated microbiological system provides the bacterial identification and antimicrobial susceptibility profile by the dilution method. Additionally, the column chromatography test is used to detect carbapenemase enzymes, including OXA-48-like. Finally, the molecular identification of the OXA-48-like enzyme was carried out by Polymerase Chain Reaction PCR amplification for the bla_OXA-48-like.

RESULTS

Seven OXA-48-like CPE strains were isolated. Notably, in all cases, the automated system issued a minimum inhibitory concentration (MIC) of ≥1 ug/mL for ertapenem and a MIC of >64/4 ug/mL for piperacillin/tazobactam. In addition, resistance category to imipenem and meropenem was found (2/7), at least one indeterminate category for any of these carbapenems (5/7), and other serine β-lactamases such as Extended-spectrum beta-lactamases (3/7) and AmpC (3/7). The immunochromatographic study confirmed the presence of the OXA-48-like enzyme in all isolates, while class A and class B were ruled out for them. Finally, the multiplex PCR, for the five isolates that could be recovered, showed amplification for carbapenemase OXA-48-like, while none of the other carpabemases was amplified for class A or class B carbapenemase genes.

CONCLUSION

We confirm the emergence of OXA-48-like CPE isolates in our cancer center and highlight the need to implement surveillance and detection measures of these strains, for controlling their dissemination. We found practical and inexpensive methodologies for the detection of OXA-48-like CPE: (1) the finding of resistance to ertapenem and piperacillin/tazobactam in the antibiogram in the absence of class A and B carbapenemases, for screening and (2) immunochromatographic study, for confirmation.

Evaluation of a Sequential Antibiotic Treatment Regimen of Ampicillin, Ciprofloxacin and Fosfomycin against Escherichia coli CFT073 in the Hollow Fiber Infection Model Compared with Simultaneous Combination Treatment

OBJECTIVE

Employ the hollow fiber infection model (HFIM) to study sequential antibiotic administration (ampicillin, ciprofloxacin and fosfomycin) using human pharmacokinetic profiles to measure changes in the rate of antibiotic resistance development and compare this to simultaneous combination therapy with the same antibiotic combinations.

METHODS

Escherichia coli CFT073, a clinical uropathogenic strain, was exposed individually to clinically relevant pharmacokinetic concentrations of ampicillin on day 1, ciprofloxacin on day 2 and fosfomycin on day 3. This sequence was continued for 10 days in the HFIM. Bacterial samples were collected at different time points to enumerate total and resistant bacterial populations. The results were compared with the simultaneous combination therapy previously studied.

RESULTS

Sequential antibiotic treatment (ampicillin-ciprofloxacin-fosfomycin sequence) resulted in the early emergence of single and multi-antibiotic-resistant subpopulations, while the simultaneous treatment regimen significantly delayed or prevented the emergence of resistant subpopulations.

CONCLUSION

Sequential administration of these antibiotic monotherapies did not significantly delay the emergence of resistant subpopulations compared to simultaneous treatment with combinations of the same antibiotics. Further studies are warranted to evaluate different sequences of the same antibiotics in delaying emergent resistance.

Clinical and Molecular Characterizations of Carbapenem-Resistant Klebsiella pneumoniae Causing Bloodstream Infection in a Chinese Hospital

Bloodstream infection (BSI) caused by carbapenem-resistant Klebsiella pneumoniae (CRKP) is a serious and urgent threat for hospitalized patients. This study aims to describe the clinical and molecular characteristics of CRKP causing BSI in a tertiary-care hospital in Beijing, China. A total of 146 CRKP strains and 39 carbapenem-susceptible K. pneumoniae (CSKP) strains collected in the hospital from 2017 to 2020 were sent for whole-genome sequencing. Univariate and multivariate analyses were used to evaluate risk factors for in-hospital mortality of CRKP-BSI cases. Thirty (20.5%) of 146 CRKP-BSI patients and three (7.7%) of 39 CSKP-BSI patients died at discharge (χ² = 3.471, P = 0.062). Multivariate logistic regression analysis indicated that age and use of urinary catheters were independent risk factors for the death of CRKP-BSI. The 146 CRKP isolates belonged to 9 sequence types (STs) and 11 serotypes, while the 39 CSKP isolates belonged to 23 STs and 27 serotypes. The mechanism of carbapenem resistance for all the CRKP strains was the acquisition of carbapenemase, mainly KPC-2 (n = 127). There were 2 predominant serotypes for ST11 CRKP, namely, KL47 (n = 82) and KL64 (n = 42). Some virulent genes, including rmpA2, iucABCD and iutA, and repB gene, which was involved in plasmid replication, were detected in all ST11-KL64 strains. Evolutionary transmission analysis suggested that ST11 CRKP strains might have evolved from KL47 into KL64 and were accompanied by multiple outbreak events. This study poses an urgent need for enhancing infection control measures in the hospital, especially in the intensive care unit where the patients are at high-risk for acquiring CRKP-BSI. IMPORTANCE CRKP-BSI is demonstrated to cause high mortality. In this study, we demonstrated that ST11 CRKP strains might carry many virulent genes. Meanwhile, outbreak events occurred several times in the strains collected. Carbapenemase acquisition (mainly KPC-2 carbapenemase) was responsible for carbapenem resistance of all the 146 CRKP strains. As 2 predominant strains, all ST11-KL64 strains, but not ST11-KL47 strains, carried rmpA2, iucABCD, iutA, as well as a plasmid replication initiator (repB). Our study suggested that the occurrence of region-specific recombination events manifested by the acquisition of some virulence genes might contribute to serotype switching from ST11-KL47 to ST11-KL64. The accumulation of virulent genes in epidemic resistant strains poses a great challenge for the prevention and treatment of BSI caused by K. pneumoniae in high-risk patients.

A Closer Look at the Laboratory Impact of Utilizing ePlex Blood Culture Identification Panels: a Workflow Analysis Using Rapid Molecular Detection for Positive Blood Cultures

Rapid identification of pathogens is critical in bloodstream infections. We evaluated the diagnostic performance of the GenMark Dx ePlex blood culture identification (BCID) panels and the adoption of the ePlex system into the clinical laboratory workflow. Nonduplicate remnant specimens of positive blood cultures were prospectively tested using ePlex panels between January and March 2020. A total of 313 unique positive blood culture specimens were tested. The identified organisms consisted of 98 Gram-negative rods (GNR), 90 Gram-positive cocci (GPC) in clusters, 62 GPC in chains, 21 Gram-positive rods, and 20 yeasts; 22 organisms were off panel. The positive percent agreement was 100% across all organisms tested after discordancy resolution, while the negative percent agreement was 100% across all targets except Corynebacterium spp., where it was 99.7%. The ePlex BCID panels accurately detected 5 pan targets and 42 antimicrobial resistance gene markers, including 31 mecA, 4 vanA, 6 CTX-M, and 1 KPC gene. The median times to result were calculated as 2.5 h for Xpert MRSA/SA in GPC in clusters, 9.5 h for Accelerate Pheno (identification and susceptibility) in GNR, 6 h for peptide nucleic acid fluorescent in situ hybridization [PNA-FISH] in yeasts, 27 h for the latex agglutination test in S. aureus, 29 h for Lancefield serotyping in GPC in chains, and 29 h for Vitek-MS in GNR. In our laboratory, the ePlex panels could substantially reduce the time to result for bloodstream infection (BSI) caused by Streptococcus spp., Enterococcus spp., and Candida spp. The highly accurate ePlex panels can help streamline laboratory efficiency in the blood bench workflow, reducing the time to result for identification of BSI pathogens. IMPORTANCE Sepsis is a leading cause of morbidity and mortality worldwide. Rapid identification of the causative agent is of critical importance for the prompt initiation of the appropriate antibiotic treatment. In this study, we evaluated the diagnostic performance of the GenMark Dx ePlex blood culture identification (BCID) panels and their adoption into the clinical laboratory workflow. We prospectively tested 313 blood culture isolates and found that ePlex BCID panels had a positive percent agreement of 100% across all organisms tested after discordancy resolution. The negative percent agreement was 100% across all targets except Corynebacterium spp., where it was 99.7%. This new rapid technology (turnaround time of ~90 min) can help streamline laboratory efficiency in the blood bench workflow, reducing the time to result for identification of BSI pathogens. Adoption should be individualized based on the needs of the patient population and capabilities of the laboratory.

Application Effect of Transparent Supervision Based on Informatization in Prevention and Control of Carbapenem-Resistant Klebsiella pneumoniae Nosocomial Infection

Objective

To explore the effect of transparent supervision model on the prevention and control of carbapenem-resistant Klebsiella pneumoniae (CRKP) nosocomial infection and the value of the autoregressive integrated moving average (ARIMA) model in predicting the incidence of CRKP infection.

Methods

A total of 46,873 inpatients from Jiawang District People's Hospital of Xuzhou between January 2019 and December 2019 (prior to COVID-19 prevention and control) were selected as the preintervention group and 45,217 inpatients from January 2020 to December 2020 (after the COVID-19 prevention and control) as the postintervention group. We performed transparent supervision on CRKP patients detected by the real-time monitoring system for nosocomial infection. Incidence and detection rate of CRKP, utilization rate of special grade hydrocarbon enzyme alkene antibiotics, hand hygiene compliance rate, qualified rate of ATP tests on surface of environmental objects, and execution rate of CRKP core prevention and control were compared between the two groups.

Results

Transparent supervision of CRKP-infected patients was conducted daily from January to December 2020, which resulted in the following: (a) the infection rate of CRKP decreased in a fluctuating manner, and the actual value of hydrocarbon alkene use rate was basically the same as the predicted value with an overall decreasing trend; (b) after the intervention, hand hygiene compliance rate increased from 53.30% to 70.24% (P < 0.001) and the ATP qualified rate increased from 53.77% to 92.24% (P < 0.001); (c) the fitted value of the ARIMA model was in good agreement with the actual value. The incidence of CRKP infection and the utilization rate of carbene antibiotics were also in good agreement with the predicted value. The average relative errors were 11% and 10.78%.

Conclusions

During the COVID-19 outbreak in 2020, the ARIMA model effectively fit and predicted the CRKP infection rate, thereby providing scientific guidance for the prevention and control of CRKP infection. In addition, the transparent supervision intervention model improved the hand hygiene compliance and environmental hygiene qualification rates of medical staff, effectively reducing CRKP cross-infection in the hospital.

Clinical Outcomes Associated with Co-infection of Carbapenem-Resistant Enterobacterales and other Multidrug-Resistant Organisms

Background

Infections with carbapenem-resistant Enterobacterales (CRE) are associated with increased risk of death. Polymicrobial infections with antimicrobial-resistance may add to the burden of clinical care and patients' clinical prognosis.

Aim

To examine the impact of CRE co-infection with other multi-drug resistant organisms (MDRO) on patient clinical outcomes.

Study Design

A retrospective observational study was conducted to compare the clinical outcomes of CRE patients who were co-infected with carbapenem-resistant Pseudomonas aeruginosa (CRPA), multidrug-resistant Acinetobacter baumannii (MDRA) and Methicillin-resistant Staphylococcus aureus (MRSA).

Results

A total of 224 CRPA and 209 MDRA co-infections with CRE were identified from 4,236 cases from 2015-2020. The overall 90-day all-cause mortality was 21.6% but increased to 35.0% and 33.5% among patients who were co-infected with CRPA and MDRA, respectively. The odds of all-cause mortality among CRE patients who were co-infected with CRPA was twice that of patients identified with CRE alone [adjusted odds ratio (AOR) = 2.02, 95% confidence interval (CI): 1.18-3.46]. Further, the odds of all-cause mortality among CRE patients who were concomitantly identified with MRSA was more than twice that of patients who were not identified with MRSA [AOR = 2.16, 95%CI:1.31-3.56]. The clinical outcome of patients with CRE did not differ significantly depending on the presence of carbapenemase genes.

Conclusion

The results show that CRPA and CRE co-infections have synergistic effects on clinical outcomes. Further investigation is necessary to understand the mechanism. Screening high risk patients for concomitant antimicrobial-resistant infections may have a significant clinical impact, including effective therapies, antibiotic stewardship, and infection control policies.

Cost-effectiveness of strategies to control the spread of carbapenemase-producing Enterobacterales in hospitals: a modelling study

Background

Spread of resistant bacteria causes severe morbidity and mortality. Stringent control measures can be expensive and disrupt hospital organization. In the present study, we assessed the effectiveness and cost-effectiveness of control strategies to prevent the spread of Carbapenemase-producing Enterobacterales (CPE) in a general hospital ward (GW).

Methods

A dynamic, stochastic model simulated the transmission of CPE by the hands of healthcare workers (HCWs) and the environment in a hypothetical 25-bed GW. Input parameters were based on published data; we assumed the prevalence at admission of 0.1%. 12 strategies were compared to the baseline (no control) and combined different prevention and control interventions: targeted or universal screening at admission (TS or US), contact precautions (CP), isolation in a single room, dedicated nursing staff (DNS) for carriers and weekly screening of contact patients (WSC). Time horizon was one year. Outcomes were the number of CPE acquisitions, costs, and incremental cost-effectiveness ratios (ICER). A hospital perspective was adopted to estimate costs, which included laboratory costs, single room, contact precautions, staff time, i.e. infection control nurse and/or dedicated nursing staff, and lost bed-days due to prolonged hospital stay of identified carriers. The model was calibrated on actual datasets. Sensitivity analyses were performed.

Results

The baseline scenario resulted in 0.93 CPE acquisitions/1000 admissions and costs 32,050 €/1000 admissions. All control strategies increased costs and improved the outcome. The efficiency frontier was represented by: (1) TS with DNS at a 17,407 €/avoided CPE case, (2) TS + DNS + WSC at a 30,700 €/avoided CPE case and (3) US + DNS + WSC at 181,472 €/avoided CPE case. Other strategies were dominated. Sensitivity analyses showed that TS + CP might be cost-effective if CPE carriers are identified upon admission or if the cases have a short hospital stay. However, CP were effective only when high level of compliance with hand hygiene was obtained.

Conclusions

Targeted screening at admission combined with DNS for identified CPE carriers with or without weekly screening were the most cost-effective options to limit the spread of CPE. These results support current recommendations from several high-income countries.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13756-022-01149-0.

Decolonization of carbapenem-resistant Klebsiella pneumoniae from the intestinal microbiota of model mice by phages targeting two surface structures

Background

Klebsiella pneumoniae is a normal component of the human gastrointestinal tract microbiota. However, in some cases, it can cause disease. Over the past 20 years, the prevalence of antibiotic-resistant bacteria, such as carbapenem-resistant K. pneumoniae (CRKP), has been increasing.

Materials and methods

We attempted to specifically eliminate CRKP from a mouse model with the human intestinal microbiota. To establish humanized microbiota-colonized mice, we administered K64 CRKP-containing human microbiota to germ-free mice by fecal microbiota transplantation. Then, we used two phages, one targeting the capsule (φK64-1) and one targeting O1 lipopolysaccharide (φKO1-1) of K64 K. pneumoniae, to eliminate CRKP.

Results

In untreated control and φKO1-1-treated K64-colonized mice, no change in CRKP was observed, while in mice treated with φK64-1, a transient reduction was observed. In half of the mice treated with both φKO1-1 and φK64-1, CRKP was undetectable in feces by PCR and culture for 60 days. However, in the other 50% of the mice, K. pneumoniae was transiently reduced but recovered 35 days after treatment.

Conclusion

Combination treatment with φK64-1 and φKO1-1 achieved long-term decolonization in 52.3% of mice carrying CRKP. Importantly, the composition of the intestinal microbiota was not altered after phage treatment. Therefore, this strategy may be useful not only for eradicating drug-resistant bacterial species from the intestinal microbiota but also for the treatment of other dysbiosis-associated diseases.

A Phase 3, Multicenter, Double-blind, Randomized Clinical Trial to Evaluate the Efficacy and Safety of Ceftolozane/Tazobactam Plus Metronidazole Versus Meropenem in Chinese Participants With Complicated Intra-abdominal Infections

OBJECTIVE

To evaluate the efficacy and safety of ceftolozane/tazobactam plus metronidazole vs meropenem plus placebo for the treatment of complicated intra-abdominal infection (cIAI) in Chinese adult participants.

METHODS

In this phase 3 clinical trial (NCT03830333), Chinese adult participants with cIAI were randomized 1:1 to receive ceftolozane/tazobactam plus metronidazole or meropenem plus placebo. The primary objective was to assess ceftolozane/tazobactam plus metronidazole for noninferiority vs meropenem for clinical response rate at the test of cure (TOC; 28 ± 2 days after study start) visit in the clinically evaluable (CE) population. Secondary end points included clinical and microbiologic responses at the TOC and end of treatment (EOT; ≤24 hours after last dose) visits and adverse event rates.

RESULTS

Clinical cure at the TOC visit in the CE population was 95.2% and 93.1% for ceftolozane/tazobactam plus metronidazole and meropenem, respectively (between-treatment difference: 2.1% [95% CI: -4.7%, 8.8%); thus, noninferiority was met. Clinical responses at the TOC and EOT visits and microbiologic responses at the TOC visit were consistent with the primary efficacy end point. Safety was comparable between study treatment groups.

CONCLUSION

In Chinese adult participants with cIAI, ceftolozane/tazobactam plus metronidazole was noninferior to meropenem, with comparable safety.