Fluoroquinolone-Resistant and Extended-Spectrum β-Lactamase-Producing Escherichia coli Infections in Patients with Pyelonephritis, United States(1)

Empirical antimicrobial prescribing for pyelonephritis in patients discharged from 15 US Emergency Departments: an opportunity for improvement

BACKGROUND

Urinary tract infections (UTIs) are commonly treated in the emergency department (ED), and unfortunately, resistance to first-line agents is increasing.

OBJECTIVES

To characterize treatment of pyelonephritis in a nationally representative sample of ED patients and to identify patient- and treatment-specific factors associated with receiving initial inactive antibiotics.

METHODS

We conducted a multicentre, observational cohort study utilizing the Emergency Medicine PHARMacotherapy Research NETwork (EMPHARM-NET), comprising 15 geographically diverse US EDs. All patients ≥18 years of age with a diagnosis of pyelonephritis between 2018 and 2020 were included. The primary endpoint was the proportion of patients who received initial inactive empirical antibiotic therapy and to identify predictive factors of inactive antibiotic therapy.

RESULTS

Of the 3714 patients evaluated, 223 had culture-positive pyelonephritis. Median patient age was 50.1 years and patients were mostly female (78.3%). Overall, 40.4% of patients received an IV antibiotic, most commonly ceftriaxone (86.7%). The most frequently prescribed antibiotics were cefalexin (31.8%), ciprofloxacin (14.3%), cefdinir (13.5%) and trimethoprim/sulfamethoxazole (12.6%). Overall, 10.3% of patients received initial inactive therapy. After adjustment in a multivariable analysis, long-acting IV antibiotic was predictive of inactive therapy (OR 0.23, 95% CI 0.07-0.83).

CONCLUSIONS

In our prospective, multicentre observational study, we found that only 40.4% of patients with pyelonephritis received empirical IV antibiotics in the ED, contributing to inactive therapy. Receipt of long-acting IV antibiotics was independently associated with a decreased rate of initial inactive therapy. This reinforces guideline recommendations to administer long-acting IV antibiotics empirically in the ED upon suspicion of pyelonephritis.

In vitro activity of cefepime/taniborbactam and comparator agents against Gram-negative bacterial bloodstream pathogens recovered from patients with cancer

Background

Taniborbactam is a β-lactamase inhibitor that, when combined with cefepime, may offer a potential treatment option for patients with serious and resistant Gram-negative bacterial (GNB) pathogens.

Objectives

This study evaluated in vitro activity of cefepime/taniborbactam and comparator agents against GNB pathogens isolated from patients with cancer at our institution.

Methods

A total of 270 GNB pathogens (2019-23) isolated from patients with cancer were tested against cefepime/taniborbactam and comparator agents commonly used for these patients. CLSI-approved broth microdilution methods were used. MIC50, MIC90, MIC range and percentage of susceptibility calculations were made using FDA breakpoints when available.

Results

Cefepime/taniborbactam showed highly potent activity against tested Enterobacterales, including isolates producing ESBLs and carbapenem-resistant Enterobacterales. At a provisional breakpoint of ≤16/4 mg/L, cefepime/taniborbactam inhibited most tested species of GNB pathogens, with overall 98.9% susceptibility, which was significantly (P < 0.0001) higher than the susceptibility of the GNB isolates to all other tested comparator agents, ranging from 39.6% for cefepime to 86.3% for ceftazidime/avibactam.

Conclusions

Our results showed that taniborbactam in combination with cefepime improved in vitro activity against GNB pathogens isolated from patients with cancer, including MDR Pseudomonas aeruginosa, carbapenem-resistant Enterobacterales, ESBL-producing Enterobacterales and Stenotrophomonas maltophilia isolates, with highest activity compared with all tested comparator agents, including other β-lactam/β-lactamase inhibitor combinations. Further studies are warranted to explore the efficacy of cefepime/taniborbactam for empirical initial treatment of GNB infections in cancer patients with high rates of febrile neutropenia requiring hospitalization.

Fluoroquinolone resistance in complicated urinary tract infections: association with the increased occurrence and diversity of Escherichia coli of clonal complex 131, together with ST1193

Introduction

Urinary tract infections (UTIs) are one of the leading causes of multidrug-resistance (MDR) spread and infection-related deaths. Escherichia coli is by far the main causative agent. We conducted a prospective study on complicated urinary tract infections (cUTIs) i) to monitor the high-risk clones that could be compromising the therapeutic management and ii) to compare the cUTI etiology with uncomplicated infections (uUTIs) occurring in the same period and health area.

Methods

154 non-duplicated E. coli recovered from cUTIs in 2020 at the Hospital Universitario Central de Asturias (Spain) constituted the study collection.

Results

Most cUTI isolates belonged to phylogroup B2 (72.1%) and met the uropathogenic (UPEC) status (69.5%) (≥3 of chuA, fyuA, vat, and yfcV genes). MDR was exhibited by 35.7% of the isolates, similarly to data observed in the uUTI collection. A significant difference observed in cUTI was the higher level of fluoroquinolone resistance (FQR) (47.4%), where the pandemic clonal groups B2-CC131 and B2-ST1193 (CH14-64) comprised 28% of the 154 E. coli, representing 52.1% of the FQR isolates. Other prevalent FQR clones were D-ST69 (CH35-27), D-ST405 (CH37-27), and B2-ST429 (CH40-20) (three isolates each). We uncovered an increased genetic and genomic diversity of the CC131: 10 different virotypes, 8 clonotypes (CH), and 2 STs. The presence of bla CTX-M-15 was determined in 12 (7.8%) isolates (all CC131), which showed 10 different core genome (cg)STs and 2 fimH types (fimH30 and fimH602) but the same set of chromosomal mutations conferring FQR (gyrA p.S83L, gyrA p.D87N, parC p.S80I, parC p.E84V, and parE p.I529L). In addition, the plasmidome analysis revealed 10 different IncF formulae in CC131 genomes.

Conclusion

We proved here that non-lactose fermenting screening, together with the detection of O25b (rfbO25b), H4 (fliCH4), and H5 (fliCH5) genes, and phylogroup and clonotyping assignation, is a reasonable approach that can be easily implemented for the surveillance of emerging high-risk clones associated with FQR spread in cUTIs, such as the uncommonly reported O25b:H4-B2-ST9126-CC131 (CH1267-30). Since E. coli CC131 and ST1193 are also involved in the community uUTIs of this health area, interventions to eradicate these MDR clones, along with surveillance for other emerging ones, are essential for antibiotic use optimization programs.

Streptococcus pneumoniae favors tolerance via metabolic adaptation over resistance to circumvent fluoroquinolones

Streptococcus pneumoniae is a major human pathogen of global health concern and the rapid emergence of antibiotic resistance poses a serious public health problem worldwide. Fluoroquinolone resistance in S. pneumoniae is an intriguing case because the prevalence of fluoroquinolone resistance does not correlate with increasing usage and has remained rare. Our data indicate that deleterious fitness costs in the mammalian host constrain the emergence of fluoroquinolone resistance both by de novo mutation and recombination. S. pneumoniae was able to circumvent such deleterious fitness costs via the development of antibiotic tolerance through metabolic adaptation that reduced the production of reactive oxygen species, resulting in a fitness benefit during infection of mice treated with fluoroquinolones. These data suggest that the emergence of fluoroquinolone resistance is tightly constrained in S. pneumoniae by fitness tradeoffs and that mutational pathways involving metabolic networks to enable tolerance phenotypes are an important contributor to the evasion of antibiotic-mediated killing.IMPORTANCEThe increasing prevalence of antibiotic resistant bacteria is a major global health concern. While many species have the potential to develop antibiotic resistance, understanding the barriers to resistance emergence in the clinic remains poorly understood. A prime example of this is fluroquinolone resistance in Streptococcus pneumoniae, whereby, despite continued utilization, resistance to this class of antibiotic remains rare. In this study, we found that the predominant pathways for developing resistance to this antibiotic class severely compromised the infectious capacity of the pneumococcus, providing a key impediment for the emergence of resistance. Using in vivo models of experimental evolution, we found that S. pneumoniae responds to repeated fluoroquinolone exposure by modulating key metabolic pathways involved in the generation of redox molecules, which leads to antibiotic treatment failure in the absence of appreciable shifts in resistance levels. These data underscore the complex pathways available to pathogens to evade antibiotic mediating killing via antibiotic tolerance.

Fluoroquinolone resistance in urinary tract infections: Epidemiology, mechanisms of action and management strategies

Background

Fluoroquinolone resistance is an issue of concern amongst physicians worldwide. In urology, fluoroquinolones are often used in the treatment of acute pyelonephritis and prostatitis, as well as infections caused by multidrug-resistant pathogens.

Aims

We aim to highlight the importance of antimicrobial stewardship and the need for ongoing biomedical research to discover novel agents in our losing battle against resistant pathogens.

Materials and methods

In this review, we survey the literature and summarise fluoroquinolone resistance as it pertains to pyelonephritis and prostatitis, as well as alternative treatment strategies and prevention of multidrug resistance.

Results

The rise of fluoroquinolone resistance in bacteria has reduced the available treatment options, often necessitating hospital admission for intravenous antibiotics, which places an additional burden on both patients and the healthcare system. Many countries such as Australia have attempted to limit fluoroquinolone resistance by imposing strict prescribing criteria, though these efforts have not been entirely successful. Solutions to overcome resistance include prevention, combination therapy and the development of novel antimicrobial agents.

Conclusions

Prevention of the proliferation of resistant organisms by antimicrobial stewardship is paramount, and urologists are obliged to be aware of responsible prescribing practices such as referring to local guidelines when prescribing. By reserving fluoroquinolones for infections in which they are truly indicated and by prescribing based on both patient and local environmental factors, we can preserve this effective resource for future use.

Risk Factors for Recurrence of Community-Onset Urinary Tract Infections Caused by Extended-Spectrum Cephalosporin-Resistant Enterobacterales

Background

Extended-spectrum cephalosporin-resistant Enterobacterales (ESCrE) are an increasingly important cause of community-onset urinary tract infections (UTIs), including recurrent infections. We evaluated risk factors for recurrence among patients with community-onset ESCrE UTI.

Methods

This retrospective cohort study included adults with community-onset ESCrE UTI in the Duke University Health System from April 2018 through December 2021. ESCrE UTI recurrence by the same species was assessed 14-180 days (ie, 6 months) after completion of antibiotic treatment. We evaluated the relationships between candidate risk factors and time to recurrence using Cox proportional hazards regression models.

Results

Among 1347 patients with community-onset ESCrE UTI, 202 (15.0%) experienced recurrent infection during the 6-month follow-up period. Independent risk factors for recurrence included neurogenic bladder (adjusted hazard ratio [aHR], 1.8 [95% confidence interval {CI}, 1.2-2.6]; P = .005), prior history of UTI (aHR, 2.4 [95% CI, 1.7-3.3]; P < .001), and fluoroquinolone nonsusceptibility of the index UTI (aHR, 1.5 [95% CI, 1.1-2.1]; P = .02). Klebsiella pneumoniae infection was associated with recurrence in univariate analysis (HR, 1.6 [95% CI, 1.1-2.1]; P = .007) but not multivariate analysis (aHR, 1.4 [95% CI, 1.0-1.9]; P = .06). Inappropriate initial or definitive antibiotic therapy was not predictive of ESCrE UTI recurrence.

Conclusions

Recurrence of community-onset ESCrE UTI was common and associated with several patient and pathogen-level risk factors. Future studies should evaluate microbial risk factors for recurrence and improve the management of ESCrE UTI.

Application of Precision Medicine Concepts in Ambulatory Antibiotic Management of Acute Pyelonephritis

Acute pyelonephritis (APN) is a relatively common community-acquired infection, particularly in women. The early appropriate antibiotic treatment of this potentially life-threatening infection is associated with improved outcomes. The international management guidelines for complicated urinary tract infections and APN recommend using oral antibiotics with <10% resistance among urinary pathogens. However, increasing antibiotic resistance rates among Escherichia coli and other Enterobacterales to fluoroquinolones, trimethoprim-sulfamethoxazole (TMP-SMX), and beta-lactams has left patients without reliable oral antibiotic treatment options for APN. This narrative review proposes using precision medicine concepts to improve empirical antibiotic therapy for APN in ambulatory settings. Whereas resistance rates to a particular antibiotic class may exceed 10% at the population-based level, the predicted antibiotic resistance rates based on patient-specific risk factors fall under 10% in many patients with APN on the individual level. The utilization of clinical tools for the prediction of fluoroquinolones, TMP-SMX, and third-generation cephalosporin resistance improves the ambulatory antibiotic management of APN. It may also reduce the need to switch antibiotic therapy later based on the in vitro antibiotic susceptibility testing results of bacterial isolates in urinary cultures. This approach may mitigate the burden of increasing antibiotic resistance in the community by ensuring that the initial antibiotic prescribed has the highest likelihood of treating APN appropriately.

The Interventions and Challenges of Antimicrobial Stewardship in the Emergency Department

Over the last decades, we have witnessed a constant increase in infections caused by multi-drug-resistant strains in emergency departments. Despite the demonstrated effectiveness of antimicrobial stewardship programs in antibiotic consumption and minimizing multi-drug-resistant bacterium development, the characteristics of emergency departments pose a challenge to their implementation. The inclusion of rapid diagnostic tests, tracking microbiological results upon discharge, conducting audits with feedback, and implementing multimodal educational interventions have proven to be effective tools for optimizing antibiotic use in these units. Nevertheless, future multicenter studies are essential to determine the best way to proceed and measure outcomes in this scenario.

Comparison of antibiotic resistance rates and outcomes among older adult patients with urinary tract infections living in long- term care hospitals and the community

OBJECTIVE

In this study, we compared the proportion of antibiotic resistance between patients who visited the emergency department (ED) with urinary tract infection (UTI) from long-term care hospitals (LTCH), which is a type of long-term care facilities (LTCF) and the community. We assessed the resulting difference in prognosis.

METHOD

Older adults who visited the ED between January and December 2019 and were diagnosed with UTI were divided into community residents and LTCH residents. We investigated the antibiotics sensitivity rates, end of therapy (EOT), and the patient's outcomes were evaluated.

RESULTS

The antibiotic resistance rate was higher in LTCH residents. LTCH residents had a higher in hospital mortality rate compared to community residents. EOT was found to be longer, and admission rate and in-hospital mortality rate were also higher in LTCH residents.

CONCLUSION

LTCF residents had a higher rate of antibiotic resistance and a poor prognosis.

The Possible Role of Probiotic Supplementation in Inflammation: A Narrative Review

The fine balance between symbiotic and potentially opportunistic and/or pathogenic microorganisms can undergo quantitative alterations, which, when associated with low intestinal biodiversity, could be responsible for the development of gut inflammation and the so-called "intestinal dysbiosis". This condition is characterized by the disbalance of a fine synergistic mechanism involving the mucosal barrier, the intestinal neuroendocrine system, and the immune system that results in an acute inflammatory response induced by different causes, including viral or bacterial infections of the digestive tract. More frequently, however, dysbiosis is induced slowly and subtly by subliminal causal factors, resulting in a chronic condition related to different diseases affecting the digestive tract and other organs and apparatuses. Studies on animal models, together with studies on humans, highlight the significant role of the gut microbiota and microbiome in the occurrence of inflammatory conditions such as metabolic syndrome and cardiovascular diseases (CVDs); neurodegenerative, urologic, skin, liver, and kidney pathologies; and premature aging. The blood translocation of bacterial fragments has been found to be one of the processes linked to gut dysbiosis and responsible for the possible occurrence of "metabolic endotoxemia" and systemic inflammation, associated with an increased risk of oxidative stress and related diseases. In this context, supplementation with different probiotic strains has been shown to restore gut eubiosis, especially if administered in long-term treatments. The aim of this review is to describe the anti-inflammatory effects of specific probiotic strains observed in clinical trials and the respective indications, highlighting the differences in efficacy depending on strain, formulation, time and duration of treatment, and dosage used.

Expansion of a Pharmacist-Led Culture Follow-Up Program to Real-Time Notification of Multidrug-Resistant Microbiology Results in the Emergency Department

Introduction: There are currently limited published data for a pharmacist-led multidrug-resistant (MDR) culture follow-up program through a collaborative drug therapy management (CDTM) agreement in the emergency department (ED). Objective: The objective of this study was to assess the impact of a pharmacist-led culture follow-up program for MDR microbiology results on ED revisit rate. Methods: A single-center quasi-experimental retrospective study was conducted comparing the outcomes before (December 2017 to March 2019) and after (April 2019 to July 2020) implementation of the ED MDR Culture program. Patients 18 years of age or older; with confirmed positive microbiology culture of extended-spectrum beta-lactamases (ESBL), methicillin-resistant Staphylococcus aureus (MRSA), and vancomycin-resistant Enterococcus (VRE) at any site; and discharged from the ED were included. The primary outcome was to evaluate ED revisit within 30 days due to antimicrobial treatment failure, defined as lack of resolution or worsening of infection. A statistical analysis was performed for categorical data using Fisher's exact test, and for continuous data using unpaired t test or Mann-Whitney U Test, when applicable. Results: A total of 130 patients were included in the analysis. Patients in the post-implementation group (n = 70) had a significant reduction in ED revisits compared to the pre-implementation group (n = 60); 9 [12.9%] versus 17 [28.3%], respectively; P = .046. Conclusion: Implementation of an ED MDR culture program was associated with significantly less ED revisits within 30 days due to antimicrobial treatment failure, thus demonstrating the expanded role of ED pharmacists in antimicrobial stewardship in the outpatient setting.

Fluoroquinolone Use Among Hospitalized Children: Diagnosis-Based Stratification to Identify Stewardship Targets

Background

As FQ (fluoroquinolone) use has shifted in pediatric populations, better metrics are needed to guide targeted antibiotic stewardship interventions and limit development of adverse events and resistance, particularly in medically complex children. In this study, we identify high-utilization groups based on underlying medical conditions and describe their relative FQ use over time.

Methods

This study is a retrospective analysis of data from the Pediatric Health Information System database from 2016 to 2020. We identify high-utilization groups based on underlying medical conditions using International Classification of Diseases, Ninth or Tenth Revision codes. We delineate overall trends in the use of FQs in the inpatient setting, including rate and proportional use by each patient group.

Results

Patients with an oncology diagnosis represent a large (25%-44%) and rising proportion (+4.8%/year, P = .001) of national FQ use over the study period. Patients with intra-abdominal infections, including appendicitis, have had a significant increase in both their relative proportional use of FQs (+0.6%/year, P = .037) and proportion of FQ use per admission encounter over the study period (+0.6%/year, P = .008). Patients with cystic fibrosis represent a decreasing proportion of overall use (-2.1%/year, P = .011) and have decreasing FQ use per inpatient encounter (-0.8%/year, P = .001).

Conclusions

Patients with an oncology diagnosis and patients with an intra-abdominal infection appear to be targets for FQ stewardship. Patients with cystic fibrosis have decreasing inpatient FQ use. Key Points: This study describes fluoroquinolone use among hospitalized children from 2016 to 2020, stratified by underlying diagnoses. These trends are used to identify high-yield antibiotic stewardship targets.

Intestinal colonization with multidrug-resistant Enterobacterales: screening, epidemiology, clinical impact, and strategies to decolonize carriers

The clinical impact of infections due to extended-spectrum β-lactamase (ESBL)- and/or carbapenemase-producing Enterobacterales (Ent) has reached dramatic levels worldwide. Infections due to these multidrug-resistant (MDR) pathogens-especially Escherichia coli and Klebsiella pneumoniae-may originate from a prior asymptomatic intestinal colonization that could also favor transmission to other subjects. It is therefore desirable that gut carriers are rapidly identified to try preventing both the occurrence of serious endogenous infections and potential transmission. Together with the infection prevention and control countermeasures, any strategy capable of effectively eradicating the MDR-Ent from the intestinal tract would be desirable. In this narrative review, we present a summary of the different aspects linked to the intestinal colonization due to MDR-Ent. In particular, culture- and molecular-based screening techniques to identify carriers, data on prevalence and risk factors in different populations, clinical impact, length of colonization, and contribution to transmission in various settings will be overviewed. We will also discuss the standard strategies (selective digestive decontamination, fecal microbiota transplant) and those still in development (bacteriophages, probiotics, microcins, and CRISPR-Cas-based) that might be used to decolonize MDR-Ent carriers.

ACR Appropriateness Criteria® Acute Pyelonephritis: 2022 Update

Acute pyelonephritis (APN) is a severe urinary tract infection (UTI) that has the potential to cause sepsis, shock, and death. In the majority of patients, uncomplicated APN is diagnosed clinically and is responsive to treatment with appropriate antibiotics. In patients who are high risk or when treatment is delayed, microabscesses may coalesce to form an acute renal abscess. High-risk patients include those with a prior history of pyelonephritis, lack of response to therapy for lower UTI or for APN, diabetes, anatomic or congenital abnormalities of the urinary system, infections by treatment-resistant organisms, nosocomial infection, urolithiasis, renal obstruction, prior renal surgery, advanced age, pregnancy, renal transplant recipients, and immunosuppressed or immunocompromised patients. Pregnant patients and patients with renal transplants on immunosuppression are at an elevated risk of severe complications. Imaging studies are often requested to aid with the diagnosis, identify precipitating factors, and differentiate lower UTI from renal parenchymal involvement, particularly in high-risk individuals. Imaging is usually not appropriate for the first-time presentation of suspected APN in an uncomplicated patient. The primary imaging modalities used in high-risk patients with suspected APN are CT, MRI, and ultrasound, although CT was usually not appropriate for initial imaging in a pregnant patient with no other complications. The ACR Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision process support the systematic analysis of the medical literature from peer-reviewed journals. Established methodology principles such as Grading of Recommendations Assessment, Development, and Evaluation or GRADE are adapted to evaluate the evidence. The RAND/UCLA Appropriateness Method User Manual provides the methodology to determine the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances in which peer-reviewed literature is lacking or equivocal, experts may be the primary evidentiary source available to formulate a recommendation.

Effect of Reduced Fluoroquinolone Use on Cephalosporin Use, Susceptibilities and Clostridioides difficile Infections

Background: Overuse of fluoroquinolones has led to concerning rates of resistance, particularly among Gram-negative organisms. They are also highly implicated as a risk factor for Clostridioides difficile infection, and reports of other serious adverse events led to recommendations to restrict their use. Our health system began targeting the reduction in unnecessary fluoroquinolone prescribing in 2018, aiming to promote their safe and effective use. Broad-spectrum cephalosporins are often used as an alternative to fluoroquinolones. We sought to evaluate whether decreased fluoroquinolone use was associated with increased third- and fourth-generation cephalosporin use and whether these changes in utilization impacted other outcomes, including C. difficile infection (CDI) rates and susceptibilities among Gram-negative organisms. Methods: This retrospective descriptive analysis included adult patients who received a fluoroquinolone or broad-spectrum cephalosporin in a three-year time period across a large healthcare system. The primary objective was to evaluate the change in days of therapy (DOT) of fluoroquinolones and third- and fourth-generation cephalosporins. Secondary objectives included rates of resistance among common Gram-negative organisms, CDI, and analyses stratified by antibiotic indication. Results: Cephalosporin use increased by an average of 1.70 DOT/1000 PD per month (p < 0.001). Additionally, fluoroquinolone use decreased by an average of 1.18 DOT/1000 PD per month (p < 0.001). C. difficile infections decreased by 0.37 infections/10,000 patient-days per month (p < 0.001). Resistance to fluoroquinolones remained stable from 2018 to 2020, and a declining trend was observed in 2021. Conclusion: This study demonstrated that reduced fluoroquinolone use in a large healthcare system was associated with increased usage of broad-spectrum cephalosporins, decreased CDI and improvements in resistance patterns.

A retrospective review of oral cephalosporins versus fluoroquinolones for the treatment of pyelonephritis

Background

The current Infectious Diseases Society of America guidelines for the treatment of acute uncomplicated pyelonephritis (AUP) advise caution when using oral beta-lactams due to concern for potentially inferior efficacy compared to fluoroquinolones (FQs) and trimethoprim-sulfamethoxazole; however, studies specifically evaluating the efficacy of oral cephalosporins (CPs) in AUP are limited.

Objective

To assess the safety and efficacy of oral CPs versus FQs for the treatment of AUP.

Design, setting and participants

This is a retrospective, chart review study conducted at a single-center, tertiary care hospital.

Measurements

The primary endpoint was treatment failure within 30 days, defined as a change in antibiotic or return to ED or clinic due to persistent symptoms. Secondary endpoints included adverse drug reactions (ADRs) and C. difficile infection (CDI) within 30 days.

Results

Of the 343 patients included in the study, treatment failure occurred in 54/338 (16.0%) patients and was similar between oral CPs and FQs (35/229 [15.3%] vs. 19/109 [17.4%]). A higher percentage of treatment failures were observed for third generation (3GC) and first generation (1GC) CPs compared to second generation CPs (2GC) (3GC: 15/65 [23.4%]; 1GC: 11/49 [22.4%]; 2GC: 9/115 [7.8%]). Documented ADRs were low (6/343 [1.7%]) and no cases of CDI were documented.

Conclusions

Oral CPs appear to be as safe and effective as FQs for the treatment of AUP. Fewer treatment failures were noted with 2GCs as compared to 3GCs and 1GCs.

High prevalence of fluoroquinolone-resistant UTI among US emergency department patients diagnosed with urinary tract infection, 2018-2020

BACKGROUND

Uropathogen resistance, fluoroquinolone-resistance (FQR), and extended spectrum beta-lactamase (ESBL), has been observed to be emerging worldwide with prevalences above recommended thresholds for routine empirical treatment. The primary aim of our study was to determine the prevalence of FQR from a geographically diverse sample of United States emergency departments (EDs).

METHODS

We conducted a multi-center, observational cohort study using a network of 15 geographically diverse US EDs. All patients ≥18 years of age with the primary or secondary diagnosis of urinary tract infection (UTI) in the ED identified using International Classification of Diseases (ICD-10) diagnosis code of cystitis, pyelonephritis, or UTI from 2018 to 2020 were included. We calculated descriptive statistics for uropathogens and susceptibilities. Logistic regression analysis was used to identify antimicrobial resistance risk factors associated with FQR Escherichia coli.

RESULTS

Among 3779 patients who met inclusion criteria, median age was 62.9 years (interquartile range [IQR]: 41-77.6) and 76.3% were female. The most common diagnoses were complicated (41.2%) and uncomplicated cystitis (40.3%). E. coli was the most common pathogen (63.2%), followed by Klebsiella pneumoniae (13.2%) and Enterococcus species (5.8%). Across all sites, overall E. coli FQ-resistance prevalence was 22.1%, ranging from 10.5 to 29.7% by site. The prevalence of ESBL-producing uropathogen was 7.4%, ranging from 3.6% to 11.6% by site. Previous IV or oral antimicrobial use in the past 90-days and history of a multi-drug resistant pathogen were associated with FQ-resistant E. coli (odds ratio [OR] 2.68, 95% confidence interval [CI]: 2.04-3.51, and OR 6.93, 95% CI: 4.95-9.70, respectively). Of the patients who had FQ-resistant E. coli or an ESBL-producing uropathogen isolated, 116 (37.1%) and 61 (36.7%) did not have any documented risk factors for resistance.

CONCLUSION

FQ-resistant E. coli is widely prevalent across US sites highlighting the need for ongoing monitoring of antimicrobial resistance and, at some locations, modification of empirical treatments.

Comparison of antimicrobial resistance in patients with obstructive pyelonephritis associated with ureteral stones and uncomplicated pyelonephritis

This study aimed to investigate the clinical outcomes of causative microorganisms in obstructive pyelonephritis associated with ureteral stones (OPU) and their antibiotic susceptibilities. This retrospective cohort study included female patients diagnosed with community-acquired acute pyelonephritis (APN) at a tertiary-care hospital between 2008 and 2017. A comparison of APN cases associated with the obstruction of the upper urinary tract by ureteral stones and APN cases without complications was performed. Propensity score (PS) matching was used to adjust the heterogeneity within each group. Of the 588 female patients with community-acquired APN, 107 were diagnosed with OPU and 481 with uncomplicated APN. After PS matching, Enterobacteriaceae strains isolated from OPU cases were more resistant to fluoroquinolones (51.9% vs 16.0%, P < .001). Extended-spectrum β-lactamase was detected in 22.2% and 21.0% of the Enterobacteriaceae strains isolated from OPU and uncomplicated APN cases, respectively (P = 1.000). The treatment failure rate was similar in OPU and uncomplicated APN groups (16.0% vs 21.0%, P = .545). Patients with OPU may be empirically treated with antibiotics in accordance with the treatment protocol for general pyelonephritis. Clinicians should exercise caution in prescribing fluoroquinolones for treating OPU.

Assessment of nationally recommended antibiotics for treatment of UTI in U.S.-Mexico border emergency departments

BACKGROUND

Urinary tract infections (UTIs) seen in the emergency department are commonly treated as an outpatient with oral antibiotics. Given that antibiotics are available for over-the-counter purchase in Mexico, there is speculation that potential misuse and overuse of antibiotics in United States-Mexico border areas could lead to antibiotic resistance patterns that would render some empiric treatments for UTIs less effective. The purpose of this study was to examine the effectiveness of Infectious Disease Society of America (IDSA) guideline-recommended antibiotics for treatment of outpatient UTI diagnosed in the emergency department. Data were collected from a county hospital on the U.S.-Mexico border with a metropolitan area of over 2 million people. Secondary analysis included frequency of urine culture isolated, resistance rates of urine pathogens, and prescriber habits.

METHODS

This study was a retrospective chart review of adult patients diagnosed and treated for UTI from August 1, 2019, to February 29, 2020. Culture results of included patients were analyzed against in vitro-tested antibiotics. Bacterial isolate frequency, resistance rates, and prescribing habits were collected.

RESULTS

A total of 985 patient charts were reviewed, of which 520 patients met inclusion criteria for analysis of prescribing habits. Of these, 329 positive bacterial culture growths were included in the analysis of antibiotic resistance rates. Oral antibiotics with comparatively lower resistance rates were amoxicillin/clavulanate, cefdinir, cefuroxime, and nitrofurantoin. Oral antibiotics with notably high resistance rates included trimethoprim-sulfamethoxazole (TMP-SMX), tetracycline, ciprofloxacin, levofloxacin, and cephalexin. Nitrofurantoin was prescribed most frequently for outpatient treatment of UTI/cystitis (41.6%) while cephalexin was the most commonly prescribed antibiotic for outpatient treatment of pyelonephritis (50%).

CONCLUSION

Our findings suggest that, while part of standard IDSA guidelines, fluoroquinolones and TMP-SMX are not ideal empiric antibiotics for treatment of outpatient UTI in the U.S.-Mexico border region studied due to high resistance rates. Although not listed as first line agents per current IDSA recommendations, 2nd and 3rd generation cephalosporins, and amoxicillin/clavulanate would be acceptable options given resistance patterns demonstrated in accordance with IDSA allowance for tailoring selection to local resistance. Nitrofurantoin appears to be consistent with recommendations and demonstrates a favorable resistance profile for treatment of outpatient UTI within this region.

Prevalence and characteristics of multidrug-resistant Escherichia coli sequence type ST131 at two academic centers in Boston and Minneapolis, USA

BACKGROUND

Escherichia coli sequence type (ST) ST131, with its emergent resistance-associated H30Rx, H30R1, and C1-M27 clonal subsets, accounts for the greatest share of extraintestinal E. coli infections and most extended-spectrum β-lactamase (ESBL)-producing E. coli.

METHODS

We characterized and compared consecutive E. coli urine isolates from two geographically distinct medical centers in Minneapolis, Minnesota (n = 172) and Boston, Massachusetts (n = 143) for ESBL phenotype, CTX-M-type ESBL genes, phylogenetic groups, selected ST131 subclones, and 40 extraintestinal virulence genes.

RESULTS

Whereas the Boston vs. Minneapolis isolates had a similar prevalence of phylogenetic groups (mainly B2: 79% vs 73%), ST131 (34% vs 28%), H30 (28% vs 21%), and H30Rx (6% vs 5%), the emerging C1-M27 subclone occurred uniquely among Boston (6%) isolates. ESBL production was more prevalent among Boston isolates (15% vs 8%) and among ST131 isolates. Identified ESBL genes included bla_CTX-M-27 (Boston only) and bla_CTX-M-15. Ciprofloxacin resistance was ST131-associated and similarly prevalent across centers. Boston isolates had higher virulence gene scores.

CONCLUSIONS

Despite numerous similarities to Minneapolis isolates, Boston ST131 isolates demonstrated more prevalent ESBL production, higher virulence gene scores, and, uniquely, the C1-M27 subclone and bla_CTX-M-27. Broader surveillance is needed to define the prevalence of ST131's globally successful C1-M27 subclone across the U.S.

Characterization, genome analysis and in vitro activity of a novel phage vB_EcoA_RDN8.1 active against multi-drug resistant and extensively drug-resistant biofilm-forming uropathogenic Escherichia coli isolates, India

AIM

We aimed to study host range, stability, genome and antibiofilm activity of a novel phage vB_EcoA_RDN8.1 active against multi-drug resistant (MDR) and extensively drug-resistant (XDR) biofilm-forming uropathogenic Escherichia coli isolates.

METHODS AND RESULTS

A novel lytic phage vB_EcoA_RDN8.1 active against UPEC strains resistant to third-generation cephalosporins, fluoroquinolones, aminoglycosides, imipenem, beta-lactamase inhibitor combination and polymyxins was isolated from community raw sewage water of Chandigarh. It exhibited a clear plaque morphology and a burst size of 250. In the time-kill assay, the maximum amount of killing was achieved at MOI 1.0. vB_EcoA_RDN8.1 belongs to the family Autographiviridae, has a genome size of 39.5 kb with a GC content of 51.6%. It was stable over a wide range of temperatures and pH. It was able to inhibit biofilm formation which may be related to an endolysin encoded by ORF 19.

CONCLUSIONS

The vB_EcoA_RDN8.1 is a novel lytic phage that has the potential for inclusion into phage cocktails being developed for the treatment of urinary tract infections (UTIs) caused by highly drug-resistant UPEC.

SIGNIFICANCE AND IMPACT OF THE STUDY

We provide a detailed characterization of a novel lytic Escherichia phage with antibiofilm activity having a potential application against MDR and XDR UPEC causing UTIs.

Intestinal Persistence of Colonizing Escherichia coli Strains, Especially ST131-H30, in Relation to Bacterial and Host Factors

BACKGROUND

Superior gut colonization may underlie the pandemic emergence of the resistance-associated H30 subclone of Escherichia coli sequence type 131 (ST131-H30). Little is known about the associated host and bacterial characteristics, or the comparative persistence of non-ST131 intestinal E. coli.

METHODS

Generic and fluoroquinolone-resistant E. coli isolates from volunteers' serial fecal samples underwent clonal analysis and extensive polymerase chain reaction (PCR)-based characterization (phylogroup, selected sequence types, virulence genes). Kaplan-Meier survival analysis and Cox proportional hazards survival analysis using penalized regression (a machine-learning method) were used to identify correlates of strain persistence.

RESULTS

Screening of 2005 subjects at the Minneapolis VA Medical Center identified 222 subjects (117 veterans, 105 human and animal household members) for longitudinal fecal surveillance. Analysis of their 585 unique-by-subject fecal E. coli strains identified multiple epidemiological, ecological, and bacterial correlates of strain persistence. ST131-H30, a strong univariable correlate of persistence, was superseded in multivariable analysis by outpatient status, fluoroquinolone resistance, and diverse (predominantly iron uptake-related) virulence genes.

CONCLUSIONS

ST131-H30 exhibits exceptional intestinal persistence, possibly due to a combination of fluoroquinolone resistance and virulence factors, which may be primarily colonization factors. This identifies both likely contributors to the ST131-H30 pandemic and potential targets for interventions against it.

Effect of Antimicrobial Stewardship on Oral Quinolone Use and Resistance Patterns over 8 Years (2013-2020)

Since 2014, several global and national guidelines have been introduced to address the problem of antimicrobial resistance. We conducted a campaign in a tertiary hospital to promote appropriate quinolone use through educational lectures in 2018. The aim of this retrospective study was to evaluate the changes in the following: prescription characteristics, trend of oral quinolone use, and antibiotic susceptibility of bacteria from 2013 to 2020. Antimicrobial use was assessed as days of therapy per 1000 patient-days. We found a significant reduction in unnecessary antibiotic prescriptions between December 2013 and December 2020. Significant negative trends were detected in the use of quinolones over 8 years (outpatients, coefficient = −0.15655, p < 0.001; inpatients, coefficient = −0.004825, p = 0.0016). In particular, the monthly mean use of quinolones among outpatients significantly decreased by 11% from 2013 to 2014 (p < 0.05) and reduced further by 31% from 2017 to 2020 (p < 0.001). A significant positive trend was observed in the susceptibility of Pseudomonas aeruginosa to levofloxacin (p < 0.001). These results demonstrate that the use of oral quinolones was further reduced following educational intervention and the bacterial susceptibility improved with optimal quinolone usage compared to that in 2013.

Identification of CTX-M Type ESBL E. coli from Sheep and Their Abattoir Environment Using Whole-Genome Sequencing

Widespread dissemination of extended-spectrum beta-lactamase (ESBL) Escherichia coli (E. coli) in animals, retail meats, and patients has been reported worldwide except for limited information on small ruminants. Our study focused on the genotypic characterization of ESBL E. coli from healthy sheep and their abattoir environment in North Carolina, USA. A total of 113 ESBL E. coli isolates from sheep (n = 65) and their abattoir environment (n = 48) were subjected to whole-genome sequencing (WGS). Bioinformatics tools were used to analyze the WGS data. Multiple CTX-M-type beta-lactamase genes were detected, namely blaCTX-M-1, blaCTX-M-14, blaCTX-M-15, blaCTX-M-27, blaCTX-M-32, blaCTX-M-55, and blaCTX-M-65. Other beta-lactamase genes detected included blaCMY-2, blaTEM-1A/B/C, and blaCARB-2. In addition, antimicrobial resistance (AMR) genes and/or point mutations that confer resistance to quinolones, aminoglycosides, phenicols, tetracyclines, macrolides, lincosamides, and folate-pathway antagonists were identified. The majority of the detected plasmids were shared between isolates from sheep and the abattoir environment. Sequence types were more clustered around seasonal sampling but dispersed across sample types. In conclusion, our study reported wide dissemination of ESBL E. coli in sheep and the abattoir environment and associated AMR genes, point mutations, and plasmids. This is the first comprehensive AMR and WGS report on ESBL E. coli from sheep and abattoir environments in the United States.

Factors Associated with Acute Community-Acquired Pyelonephritis Caused by Extended-Spectrum β-Lactamase-Producing Escherichia coli

This study aimed to identify the factors associated with the presence of extended-spectrum ß-lactamase-(ESBL) in patients with acute community-acquired pyelonephritis (APN) caused by Escherechia coli (E. coli), with a view of optimising empirical antibiotic therapy in this context. We performed a retrospective analysis of patients with community-acquired APN and confirmed E. coli infection, collecting data related to demographic characteristics, comorbidities, and treatment. The associations of these factors with the presence of ESBL were quantified by fitting multivariate logistic models. Goodness-of-fit and predictive performance were measured using the ROC curve. We included 367 patients of which 51 presented with ESBL, of whom 90.1% had uncomplicated APN, 56.1% were women aged ≤55 years, 33.5% had at least one mild comorbidity, and 12% had recently taken antibiotics. The prevalence of ESBL-producing E. coli was 13%. In the multivariate analysis, the factors independently associated with ESBL were male sex (OR 2.296; 95% CI 1.043-5.055), smoking (OR 4.846, 95% CI 2.376-9.882), hypertension (OR 3.342, 95% CI 1.423-7.852), urinary incontinence (OR 2.291, 95% CI 0.689-7.618) and recurrent urinary tract infections (OR 4.673, 95% CI 2.271-9.614). The area under the ROC curve was 0.802 (IC 95% 0.7307-0.8736), meaning our model can correctly classify an individual with ESBL-producing E. coli infection in 80.2% of cases.

Intravenous Antibiotic Susceptibility for Urinary Tract Infection Prior to Emergency Department Discharge

Background

Urinary tract infection (UTI) is a common infectious disease managed in the emergency department (ED). Patients may be initially treated with an intravenous (IV) antibiotic and subsequently discharged with an oral antibiotic regimen.

Objective

The purpose of this study was to determine whether the current Infectious Diseases Society of America guideline recommendation for an initial dose of long-acting IV antibiotic for treatment of UTI when the prevalence of fluoroquinolone resistance exceeds 10% improves the likelihood of providing in vitro susceptibility to the isolated uropathogen.

Methods

This was a retrospective study of patients in ED presenting between May 2009 and August 2018 who received treatment for UTI. The primary outcome was susceptibility of uropathogen to the IV antibiotic administered. Secondary outcomes included susceptibility to the oral antibiotic regimen prescribed at discharge, repeat health care visit within 30 days related to UTI follow-up, adverse events (AEs) associated with antibiotic use, and identification of risk factors associated with pathogen resistance.

Results

A total of 255 patients were included for analysis. Of these patients, 230 (90.2%) had pathogens susceptible to the administered IV antibiotic. The oral regimen susceptibility was 81.6% with 29 patients returning for UTI follow-up and 4 patients reporting AEs related to antibiotic use. Men and long-term care facility residents were more likely to have resistant uropathogens.

Conclusion

Administration of a long-acting IV antibiotic for treatment of UTI prior to ED discharge is recommended when the fluoroquinolone resistance rate exceeds 10% to improve in vitro susceptibility coverage.

Advances in novel antibiotics to treat multidrug-resistant gram-negative bacterial infections

Antimicrobial resistance is a growing threat to public health and an increasingly common problem for acute care physicians to confront. Several novel antibiotics have been approved in the past decade to combat these infections; however, physicians may be unfamiliar with how to appropriately utilize them. The purpose of this review is to evaluate novel antibiotics active against resistant gram-negative bacteria and highlight clinical information regarding their use in the acute care setting. This review focuses on novel antibiotics useful in the treatment of infections caused by resistant gram-negative organisms that may be seen in the acute care setting. These novel antibiotics include ceftolozane/tazobactam, ceftazidime/avibactam, meropenem/vaborbactam, imipenem/cilistatin/relebactam, cefiderocol, plazomicin, eravacycline, and omadacycline. Acute care physicians should be familiar with these novel antibiotics so they can utilize them appropriately.

Highly Active Cranberry's Polyphenolic Fraction: New Advances in Processing and Clinical Applications

Cranberry is a fruit originally from New England and currently growing throughout the east and northeast parts of the USA and Canada. The supplementation of cranberry extracts as nutraceuticals showed to contribute to the prevention of urinary tract infections, and most likely it may help to prevent cardiovascular and gastroenteric diseases, as highlighted by several clinical trials. However, aiming to validate the efficacy and safety of clinical applications as long-term randomized clinical trials (RCTs), further investigations of the mechanisms of action are required. In addition, a real challenge for next years is the standardization of cranberry’s polyphenolic fractions. In this context, the optimization of the extraction process and downstream processing represent a key point for a reliable active principle for the formulation of a food supplement. For this reason, new non-conventional extraction methods have been developed to improve the quality of the extracts and reduce the overall costs. The aim of this survey is to describe both technologies and processes for highly active cranberry extracts as well as the effects observed in clinical studies and the respective tolerability notes.

Fluoroquinolone-Transition Metal Complexes: A Strategy to Overcome Bacterial Resistance

Fluoroquinolones (FQs) are antibiotics widely used in the clinical practice due to their large spectrum of action against Gram-negative and some Gram-positive bacteria. Nevertheless, the misuse and overuse of these antibiotics has triggered the development of bacterial resistance mechanisms. One of the strategies to circumvent this problem is the complexation of FQs with transition metal ions, known as metalloantibiotics, which can promote different activity and enhanced pharmacological behaviour. Here, we discuss the stability of FQ metalloantibiotics and their possible translocation pathways. The main goal of the present review is to frame the present knowledge on the conjunction of biophysical and biological tools that can help to unravel the antibacterial action of FQ metalloantibiotics. An additional goal is to shed light on the studies that must be accomplished to ensure stability and viability of such metalloantibiotics. Potentiometric, spectroscopic, microscopic, microbiological, and computational techniques are surveyed. Stability and partition constants, interaction with membrane porins and elucidation of their role in the influx, determination of the antimicrobial activity against multidrug-resistant (MDR) clinical isolates, elucidation of the mechanism of action, and toxicity assays are described for FQ metalloantibiotics.

The prevalence and predictors of extended spectrum B-lactamase urinary tract infections among emergency department patients: A retrospective chart review

BACKGROUND AND IMPORTANCE

Inadequate initial antibiotic treatment of ESBL urinary tract infections (UTI) can lead to increase in the number of antibiotics used, return visits, longer hospitalizations, increased morbidity and mortality and increased costs. Given the important health implications on patients, this study aimed to examine the prevalence and predictors of ESBL UTIs among Emergency Department (ED) patients of a tertiary care center in Beirut, Lebanon.

DESIGN, SETTING AND PARTICIPANTS

Single-center retrospective observational study involving all adult UTI patients who presented to the ED of the American University of Beirut Medical Center, a tertiary care center between August 2019 and August 2020.

RESULTS

Out of the 886 patients that were included, 24.9% had an ESBL organism identified by urine culture. They had higher bladder catheter use within the previous 90 days, antibiotic use within last 90 days, and were more likely to have a history of an ESBL producing isolate from any body site in the last year. Antibiotic use in the last 90 days and a history of ESBL producing isolate at any site in the previous year were significantly associated with developing an ESBL UTI (OR = 1.66, p = 0.001 and OR = 2.53, p < 0.001 respectively). Patients diagnosed with cystitis were less likely to have an ESBL organism (OR = 0.4 95%CI [0.20-0.81], p = 0.01) CONCLUSION: The prevalence of ESBL organisms was found to be 24.9% in urinary tract infections. The predictors of an ESBL UTI infection were antibiotic use in the last 90 days, a history of ESBL producing isolate at any site in the previous year. Based on the findings of our study, we can consider modifying initial empiric antibiotic treatment for patients presenting with a UTI with the above stated risk factors.

Pharmacist-led Penicillin Allergy Assessment in the Emergency Department Reduced Empiric Fluoroquinolone Use

In a retrospective, quasi-experimental study of 380 adult patients with a reported penicillin allergy who received antibiotics at a community hospital emergency department, a pharmacist-led penicillin allergy assessment via medical records review and patient interview improved guideline-preferred antibiotic use by 13% (P = .018) and reduced fluoroquinolone use by 11% (P = .035).

Third-Generation Cephalosporin Resistance and Associated Discordant Antibiotic Treatment in Emergency Department Febrile Urinary Tract Infections

STUDY OBJECTIVE

Third-generation cephalosporin-resistant (3GCR) Escherichia coli, Klebsiella pneumoniae, and Proteus mirabilis (EKP) are an increasingly common cause of community-onset urinary tract infections (UTIs) in the United States. The 3GCR antimicrobial resistance pattern in these Enterobacterales species is most commonly due to production of extended-spectrum β-lactamases. We sought to provide contemporary, emergency department (ED)-focused data on 3GCR-EKP UTI regional prevalence, presentation, antibiotic susceptibility, and empiric treatment patterns, and outcomes.

METHODS

We performed a retrospective cohort study of all adults admitted with a febrile UTI at 21 Kaiser Permanente Northern California EDs between January 2017 and June 2019. Inclusion criteria included fever; admitting diagnosis of UTI, pyelonephritis, or sepsis; and ED urine culture with greater than 100,000 colony-forming units/mL of an EKP species. 3GCR was defined as in vitro resistance to ceftriaxone, ceftazidime, or both. 3GCR-EKP cases were compared with non-3GCR-EKP controls for the following: demographics, comorbidities, presenting clinical features, urinary isolate antimicrobial susceptibility, treatment, and clinical outcomes. The primary outcome measure was the rate of discordant initial empiric antibiotic treatment (administered within 6 hours of ED arrival) when compared with antimicrobial susceptibility testing. Secondary outcomes included hospital length of stay and 90-day mortality, adjusted for comorbidities and severity of illness.

RESULTS

There were 4,107 patients (median age 73 years and 35% men) who met study inclusion criteria. Of these patients, 530 (12.9%) had a 3GCR-EKP urinary tract infection. The proportion of subjects possessing risk factors for a health care-associated or extended-spectrum β-lactamase infection was 92.8% of case patients and 86.1% of controls. When comparing 3GCR-EKP case and non-3GCR-EKP control isolates, ciprofloxacin susceptibility rates were 21% versus 88%, and piperacillin/tazobactam susceptibility rates were 89% versus 97%, respectively. Initial empiric antibiotic therapy was discordant with antimicrobial susceptibility testing results in 63% of case patients versus 7% of controls (odds ratio 21.0; 95% confidence interval 16.9 to 26.0). The hospital length of stay was longer for 3GCR-EKP case patients, with an adjusted mean difference of 29.7 hours (95% CI 19.0 to 40.4). Ninety-day mortality was 12% in case patients versus 8% in controls (adjusted odds ratio 1.56; 95% confidence interval 1.07 to 2.28).

CONCLUSION

In this large, 2017 to 2019 Northern California ED study, nearly 13% of febrile EKP UTIs requiring hospitalization were caused by 3GCR-EKP, and in these cases, initial empiric therapy was often discordant with antimicrobial susceptibility testing. 3GCR-EKP infections were associated with a longer hospital length of stay and higher 90-day mortality. Similar data from other regions and for outpatient UTIs are needed.

Large Fecal Reservoir of Escherichia coli Sequence Type 131-H30 Subclone Strains That Are Shared Within Households and Resemble Clinical ST131-H30 Isolates

BACKGROUND

Emerging antimicrobial-resistant Escherichia coli represent mainly the nested (fluoroquinolone-resistant [FQR]) H30R and H30Rx subclones within sequence type 131 (ST131). Intestinal colonization and within-household transmission may underlie H30R's emergence.

METHODS

We screened fecal samples from 741 volunteers (383 veterans, 358 household members, including pets) for ST131 and FQR E. coli (FQREC) and used molecular profiling to resolve unique strains. Selected strains underwent PCR-based detection of phylogroups, sequence types (STs), H30, H30Rx, and 53 virulence genes (VGs). Within-household strain sharing was compared with household, host, and bacterial characteristics. Fecal isolates were compared with clinical isolates.

RESULTS

Colonization prevalence was 5.1% for H30R, 8% for ST131 (67% FQREC), and 10% for FQREC (52% ST131). ST131 isolates exhibited more VGs than non-ST131 isolates. Strain sharing (27% of multisubject households, 18% of corresponding subjects) was associated with the elderly, FQREC, H30R, H30Rx, ST73, and specific VGs. Fecal ST131 and FQREC isolates resembled contemporaneous and historical clinical isolates according to all studied traits.

CONCLUSIONS

Veterans and their human household members commonly carry and extensively share FQREC, predominantly H30R, thereby likely facilitating the ST131 pandemic. Strain sharing corresponds with multiple bacterial characteristics, including FQ resistance and specific VGs, which may promote intestinal colonization and/or host-to-host transmission.

Impact of Beta-Lactam Allergies on Selection of Antimicrobials in an Inpatient Setting Among Veteran Population

Purpose

Beta-lactam antibiotics are among the most common and widely used antibiotics. However, reported allergy to this class of antibiotics is also common, leading to the use of alternative broad-spectrum antibiotics by healthcare providers. This has led to the emergence of various negative health outcomes. The purpose of the study is to investigate the impact of using alternative antibiotics secondary to a beta-lactam allergy among U.S. veterans who have otherwise multiple comorbidities.

Methods

This retrospective observational analysis was conducted over a 5-year period (January 1, 2011 to December 31, 2016) at the Memphis Veterans Affairs Medical Center (VAMC). Admitted patients with a documented beta-lactam allergy were categorized to preferred or non-preferred status based on initial antibiotic therapy antibiotic, allergy history, published guidelines, and local antibiogram. Preferred therapy was defined as the optimal antibiotic treatment for a given indication based on patient allergy history, published Infectious Disease Society of America guidelines, and local antibiogram of Memphis VAMC. The therapy was classified as “non-preferred” if it did not satisfy the preferred therapy criteria. Non-preferred treatments were further assessed for appropriateness based on indication and patient-specific factors. Chi-square and Fisher’s exact tests were conducted to find a difference in rates of negative sequelae among patients receiving preferred vs. non-preferred treatments and appropriate vs. inappropriate treatments.

Findings

Of the 1806 admissions identified, data were collected on 95 unique patients with 147 different antibiotic regimens. There were 68 (52%) preferred treatment regimens and 64 (48%) non-preferred treatment regimens. Of the 64 non-preferred treatments, 43 (67%) were inappropriate. There was a statistically significant decrease in the number of adverse drug events and in the combined negative sequelae outcome among patients receiving preferred therapy vs. non-preferred therapy (2 vs. 12; P &lt; .01 and 11 vs. 23; P &lt; .01, respectively).

Implications

The receipt of non-preferred antibiotic therapy among veterans with a recorded beta-lactam allergy may be associated with an increased risk of developing negative outcomes. Among military personnel, removing unnecessary beta-lactam allergies would improve readiness with optimal antibiotic choices and avoidance of unnecessary risks, expediting return to full duty.

Travel-Related Antimicrobial Resistance: A Systematic Review

There is increasing evidence that human movement facilitates the global spread of resistant bacteria and antimicrobial resistance (AMR) genes. We systematically reviewed the literature on the impact of travel on the dissemination of AMR. We searched the databases Medline, EMBASE and SCOPUS from database inception until the end of June 2019. Of the 3052 titles identified, 2253 articles passed the initial screening, of which 238 met the inclusion criteria. The studies covered 30,060 drug-resistant isolates from 26 identified bacterial species. Most were enteric, accounting for 65% of the identified species and 92% of all documented isolates. High-income countries were more likely to be recipient nations for AMR originating from middle- and low-income countries. The most common origin of travellers with resistant bacteria was Asia, covering 36% of the total isolates. Beta-lactams and quinolones were the most documented drug-resistant organisms, accounting for 35% and 31% of the overall drug resistance, respectively. Medical tourism was twice as likely to be associated with multidrug-resistant organisms than general travel. International travel is a vehicle for the transmission of antimicrobial resistance globally. Health systems should identify recent travellers to ensure that adequate precautions are taken.

Travel to Mexico and uropathogen-antibiotic susceptibility mismatch in the emergency department

INTRODUCTION

International travel results in an increased risk of colonization and infection with multidrug-resistant organisms. This study aimed to determine if recent travel to Mexico affects the rate of uropathogen-antibiotic susceptibility mismatch (UASM) in outpatients treated for urinary tract infection (UTI) in a South Texas emergency department (ED).

METHODS

A retrospective cohort of adult patients presenting to the ED and treated outpatient for UTI from October 1, 2014, to February 25, 2020, was conducted at a community hospital located within approximately 15 miles of the United States-Mexico border. Rates of UASM were compared between patients with a history of recent travel to Mexico and those who have not recently traveled.

RESULTS

A total of 192 patients were included, with 64 in the travel to Mexico group and 128 in the no travel group. UASM was significantly higher in the recent travel to Mexico group when compared to the no travel group (RR 1.49, 95% CI 1.03-2.13). Antibiotics most commonly associated with UASM included fluoroquinolones, cephalexin, and sulfamethoxazole-trimethoprim. There was no significant difference between the rates of resistance to first-line agents for the treatment of UTI among the two groups.

CONCLUSION

In addition to known antibiotic resistance risk factors, recent travel to Mexico may increase the risk of UASM for ED patients with UTI. Considering the potential consequences of UTI treatment failure, antimicrobial stewardship services in the ED should include screening for antibiotic resistance risk factors and urine culture follow-up to ensure appropriate outpatient antibiotic therapy, especially among patients with recent international travel.

Resistance among urinary tract pathogens collected in Europe during 2018

OBJECTIVES

Escherichia coli, Klebsiella pneumoniae and Proteus mirabilis are urinary tract infection (UTI) pathogens and extended spectrum β-lactamase (ESBL)-producing pathogens exhibit co-resistance to oral fluoroquinolones (FQ) and trimethoprim-sulphamethoxazole (TMP-SMX). This study assessed the prevalence of ESBL phenotypes and co-resistance to FQ and TMP-SMX.

METHODS

In total, 766 E. coli, 260 K. pneumoniae and 104 P. mirabilis from UTIs in 18 countries were evaluated for susceptibility in the SENTRY surveillance programme, and results interpreted using EUCAST criteria.

RESULTS

E. coli, K. pneumoniae and P. mirabilis accounted for 57.1%, 11.3% and 7.8%, respectively, of the isolates. Among E. coli, resistance to levofloxacin and TMP-SMX ranged from 21.8% to 32.7% for all isolates increasing to 66.5-67.0% among those with a ESBL phenotype (17.9% of all UTI E. coli from Europe were ESBL phenotypes). In contrast, all E. coli were susceptible to meropenem. For K. pneumoniae, resistance rates for levofloxacin and TMP-SMX were 32.2-40.0% increasing to 69.1-78.6% for ESBL phenotypes. Meropenem was the most active agent, with 7.7% resistance. Among P. mirabilis resistance to levofloxacin and TMP-SMX was 26-38.5% and increased to 100% for ESBL phenotypes. No meropenem-resistant P. mirabilis were reported.

CONCLUSIONS

High co-resistance rates were observed for oral antibiotics among ESBL phenotypes raising concerns regarding empiric use of FQ and TMP-SMX for treating resistant UTIs outside of the hospital. In contrast, intravenous carbapenems retain activity against resistant UTI pathogens. New oral options with the spectrum of the carbapenems would address an unmet need for managing resistant UTIs.

Genotypic antimicrobial resistance characterization of E. coli from dairy calves at high risk of respiratory disease administered enrofloxacin or tulathromycin

The objective of this study was to evaluate the longitudinal effect of enrofloxacin or tulathromycin use in calves at high risk of bovine respiratory disease (BRD) on antimicrobial resistance genes and mutation in quinolone resistance-determining regions (QRDR) in fecal E. coli. Calves at high risk of developing BRD were randomly enrolled in one of three groups receiving: (1) enrofloxacin (ENR; n = 22); (2) tulathromycin (TUL; n = 24); or (3) no treatment (CTL; n = 21). Fecal samples were collected at enrollment and at 7, 28, and 56 days after beginning treatment, cultured for Escherichiacoli (EC) and DNA extracted. Isolates were screened for cephalosporin, quinolone and tetracycline resistance genes using PCR. QRDR screening was conducted using Sanger sequencing. The only resistance genes detected were aac(6′)Ib-cr (n = 13), bla-CTX-M (n = 51), bla-TEM (n = 117), tetA (n = 142) and tetB (n = 101). A significantly higher detection of gyrA mutated at position 248 at time points 7 (OR = 11.5; P value = 0.03) and 28 (OR = 9.0; P value = 0.05) was observed in the ENR group when compared to calves in the control group. Our findings support a better understanding of the potential impacts from the use of enrofloxacin in calves on the selection and persistence of resistance.

Emergence of Extended-Spectrum β-Lactamase Urinary Tract Infections Among Hospitalized Emergency Department Patients in the United States

STUDY OBJECTIVE

Enterobacteriaceae resistant to ceftriaxone, mediated through extended-spectrum β-lactamases (ESBLs), commonly cause urinary tract infections worldwide, but have been less prevalent in North America. Current US rates are unknown. We determine Enterobacteriaceae antimicrobial resistance rates among US emergency department (ED) patients hospitalized for urinary tract infection.

METHODS

We prospectively enrolled adults hospitalized for urinary tract infection from 11 geographically diverse university-affiliated hospital EDs during 2018 to 2019. Among participants with culture-confirmed infection, we evaluated prevalence of antimicrobial resistance, including that caused by ESBL-producing Enterobacteriaceae, resistance risk factors, and time to in vitro-active antibiotics.

RESULTS

Of 527 total participants, 444 (84%) had cultures that grew Enterobacteriaceae; 89 of 435 participants (20.5%; 95% confidence interval 16.9% to 24.5%; 4.6% to 45.4% by site) whose isolates had confirmatory testing had bacteria that were ESBL producing. The overall prevalence of ESBL-producing Enterobacteriaceae infection among all participants with urinary tract infection was 17.2% (95% confidence interval 14.0% to 20.7%). ESBL-producing Enterobacteriaceae infection risk factors were hospital, long-term care, antibiotic exposure within 90 days, and a fluoroquinolone- or ceftriaxone-resistant isolate within 1 year. Enterobacteriaceae resistance rates for other antimicrobials were fluoroquinolone 32.3%, gentamicin 13.7%, amikacin 1.3%, and meropenem 0.3%. Ceftriaxone was the most common empirical antibiotic. In vitro-active antibiotics were not administered within 12 hours of presentation to 48 participants (53.9%) with ESBL-producing Enterobacteriaceae infection, including 17 (58.6%) with sepsis. Compared with other Enterobacteriaceae infections, ESBL infections were associated with longer time to in vitro-active treatment (17.3 versus 3.5 hours).

CONCLUSION

Among adults hospitalized for urinary tract infection in many US locations, ESBL-producing Enterobacteriaceae have emerged as a common cause of infection that is often not initially treated with an in vitro-active antibiotic.

Comparison between Exposure of Ciprofloxacin and Cefotaxime on Developing of Escherichia coli ESBL

This study aimed to compare ciprofloxacin and cefotaxime exposure to develop ESBL producing Escherichia coli (E. coli). A total of 16 isolates of cefotaxime sensitive E. coli and ciprofloxacin were exposed to ciprofloxacin and cefotaxime for 14 days using the Kirby-Bauer antibiotic disc diffusion method. Colonies that grew on the edge of the inhibiting zone were exposed each day by the same method. Furthermore, we observed the occurrence of resistance to cefotaxime as ESBL screening test. Isolates were resistant, the following day the ESBL was confirmed by the Modified Double Disk Sinergy Test (MDDST) method using Cefotaxime (CTX), Ceftazidime (CAZ), Aztreonam (ATM), and Amoxilin Clavulanate (AMC) antibiotic discs. From 16 isolates of ESBL producing E. coli exposed to ciprofloxacin, it was obtained 4 (25%) to ESBL E. coli. ESBL production occurred after E. coli was exposed to ciprofloxacin on days 5, 6, 7, and 12. While those exposed to cefotaxime none becomes ESBL E. coli. There was no difference between ciprofloxacin and cefotaxime exposure to develop ESBL producing E. coli (p=0.101; Chi-square).

Implementation of a Urinary Tract Infection Treatment Protocol to Improve Prescribing Practices in the Long-Term Care Facility of a Veteran’s Healthcare System

Urinary tract infections (UTIs) are a commonly diagnosed problem in long-term care facilities (LTCFs), but antimicrobial treatment is often incorrectly prescribed. Although bacterial resistance to antimicrobials commonly used for UTIs, such as trimethoprim/sulfamethoxazole and fluoroquinolones, has been dramatically increasing, they are still commonly prescribed. The purpose of this project was to determine if implementation of a standard treatment protocol for UTIs, which emphasized correct UTI diagnosis and use of nitrofurantoin and cefpodoxime/ceftriaxone as empiric therapy per the institutional antibiogram, changed clinician prescribing practices. This quasi-experimental model utilized two years of pre-intervention and two years of post-intervention data. Three hundred patient encounters were included. Antibiotics prescribed in the pre-intervention period included: trimethoprim/sulfamethoxazole (32%), ciprofloxacin (14%), amoxicillin (13%), levofloxacin (9%), cefpodoxime (9%), ceftriaxone (8%), amoxicillin/clavulanate (5%), nitrofurantoin (4%), and other (6%). By contrast, antibiotics prescribed in the post-intervention period included: cefpodoxime (46%), nitrofurantoin (30%), ceftriaxone (10%), trimethoprim/sulfamethoxazole (8%), amoxicillin/clavulanate (1%), and other (5%). These differences in prescribed drug between the pre-intervention and post-intervention encounters were statistically significant (p < 0.001). Overall, appropriate empiric treatment was prescribed in only 48/217 encounters (22%) during the pre-intervention period, but this increased to 73/83 encounters (88%) in the post-intervention period (p < 0.001). The results indicate that the treatment protocol was successful in changing prescribing practices and decreasing the use of inappropriate antimicrobials at the LTCF.

Differential Trends in Extended-Spectrum Beta-Lactamase-Producing Escherichia coli Infections in Four Health Care Facilities in a Single Metropolitan Area: A Retrospective Analysis

Background: Prevalence of extended-spectrum beta-lactamase-producing Escherichia coli (ESBL-E. coli) is increasing worldwide, but greatly varies geographically. We compared the prevalence of ESBL-E. coli infections at four distinct health care facilities in San Francisco, California. Methods: Antimicrobial susceptibility reports were obtained for E. coli isolates from (1) a county hospital, (2) a public skilled nursing facility, (3) a university hospital, and (4) a Veterans Affairs (VA) Medical Center. We compared change in frequency of ESBL-E. coli and antimicrobial resistance to trimethoprim-sulfamethoxazole between 2012 and 2018. Results: From 2012 to 2018, frequency of ESBL-E. coli increased in urine and nonurine isolates from the county hospital (urine: 1.1% per year, 95% confidence interval [CI]: 0.5-1.6, p < 0.01; nonurine: 1.9% per year, 95% CI: 0.9-2.9, p < 0.01) and in urine isolates from the VA hospital (0.9% per year, 95% CI: 0.3-1.4, p < 0.01). The frequency of trimethoprim-sulfamethoxazole resistance fluctuated in all facilities. Conclusions: At the skilled nursing facility, the prevalence of ESBL-E. coli was highest, but remained stable over time, while the prevalence of ESBL-E. coli increased among urine and nonurine isolates at the county hospital and urine isolates at the VA hospital. The temporal trend of ESBL-E. coli infections, even within one city, varied by health care facility.

Decreased Outpatient Fluoroquinolone Prescribing Using a Multimodal Antimicrobial Stewardship Initiative

Background

Fluoroquinolones are antibiotics prescribed in the outpatient setting, though they have serious side effects. This study evaluates the impact of stewardship interventions on total and inappropriate prescribing of fluoroquinolones in outpatient settings in a large county hospital and health system.

Methods

In an effort to decrease inappropriate outpatient fluoroquinolone usage, a multimodal antimicrobial stewardship initiative was implemented in November 2016. Education regarding the risks, benefits, and appropriate uses of fluoroquinolones was provided to providers in different outpatient settings, Food and Drug Administration warnings were added to all oral fluoroquinolone orders, an outpatient order set for cystitis treatment was created, and fluoroquinolone susceptibilities were suppressed when appropriate. Charts from October 2016, 2017, and 2018 were retrospectively reviewed if the patient encounter occurred in primary care clinics, emergency departments, or urgent care centers within Parkland Health & Hospital System and a fluoroquinolone was prescribed. Inappropriate use was defined as a fluoroquinolone prescription for cystitis, bronchitis, or sinusitis in a patient without a history of Pseudomonas aeruginosa or multidrug-resistant organisms and without drug allergies that precluded use of other oral antibiotics.

Results

Total fluoroquinolone prescriptions per 1000 patient visits decreased significantly by 39% (P < .01), and inappropriate fluoroquinolone use decreased from 53% to 34% (P < .01). More than 90% of inappropriate fluoroquinolone prescriptions were given for cystitis, while bronchitis and sinusitis accounted for only 4.4% and 1.6% of inappropriate indications, respectively.

Conclusion

A multimodal stewardship initiative appears to effectively reduce both total and inappropriate outpatient fluoroquinolone prescriptions.

Developmental loss, but not pharmacological suppression, of renal carbonic anhydrase 2 results in pyelonephritis susceptibility

Carbonic anhydrase II knockout (Car2^-/-) mice have depleted numbers of renal intercalated cells, which are increasingly recognized to be innate immune effectors. We compared pyelonephritis susceptibility following reciprocal renal transplantations between Car2^-/- and wild-type mice. We examined the effect of pharmacological CA suppression using acetazolamide in an experimental murine model of urinary tract infection. Car2^-/- versus wild-type mice were compared for differences in renal innate immunity. In our transplant scheme, mice lacking CA-II in the kidney had increased pyelonephritis risk. Mice treated with acetazolamide had lower kidney bacterial burdens at 6 h postinfection, which appeared to be due to tubular flow from diuresis because comparable results were obtained when furosemide was substituted for acetazolamide. Isolated Car2^-/- kidney cells enriched for intercalated cells demonstrated altered intercalated cell innate immune gene expression, notably increased calgizzarin and insulin receptor expression. Intercalated cell number and function along with renal tubular flow are determinants of pyelonephritis risk.

All-electrical monitoring of bacterial antibiotic susceptibility in a microfluidic device

The lack of rapid antibiotic susceptibility tests adversely affects the treatment of bacterial infections and contributes to increased prevalence of multidrug-resistant bacteria. Here, we describe an all-electrical approach that allows for ultrasensitive measurement of growth signals from only tens of bacteria in a microfluidic device. Our device is essentially a set of microfluidic channels, each with a nanoconstriction at one end and cross-sectional dimensions close to that of a single bacterium. Flowing a liquid bacteria sample (e.g., urine) through the microchannels rapidly traps the bacteria in the device, allowing for subsequent incubation in drugs. We measure the electrical resistance of the microchannels, which increases (or decreases) in proportion to the number of bacteria in the microchannels. The method and device allow for rapid antibiotic susceptibility tests in about 2 h. Further, the short-time fluctuations in the electrical resistance during an antibiotic susceptibility test are correlated with the morphological changes of bacteria caused by the antibiotic. In contrast to other electrical approaches, the underlying geometric blockage effect provides a robust and sensitive signal, which is straightforward to interpret without electrical models. The approach also obviates the need for a high-resolution microscope and other complex equipment, making it potentially usable in resource-limited settings.

Impact of an Antimicrobial Stewardship Program on Resistance to Fluoroquinolones of Urinary Enterobacteriaceae Isolated From Nursing Home Residents: A Retrospective Cohort Study

OBJECTIVES

This study investigated the impact of an antimicrobial stewardship program on fluoroquinolone (FLQ) resistance in urinary Enterobacteriaceae isolated from residents of 3 French nursing homes.

DESIGN

A multicentric retrospective before-and-after study was conducted.

SETTING AND PARTICIPANTS

All the first urinary Enterobacteriaceae isolates obtained from nursing home residents were included. Two time frames were analyzed: 2013-2015 and 2016-2017.

METHODS

The antimicrobial stewardship program started in 2015 and was based on (1) 1-day training for use of an "antimicrobial stewardship kit for nursing homes;" and (2) daily support and training of the coordinating physician by an antibiotic mobile team (AMT) in 2 of 3 nursing homes.

RESULTS

Overall, 338 urinary isolates were analyzed. Escherichia coli was the most frequent species (212/338, 63%). A significant reduction of resistance to ofloxacin was observed between 2013-2015 and 2016-2017 in general (Δ = -16%, P = .004) and among isolates obtained from patients hospitalized in the county nursing home with AMT support (Δ = -28%, P < .01). A nonstatistically significant reduction in ofloxacin resistance was also observed in the hospital nursing home with AMT support (Δ = -18%, P = .06).

CONCLUSIONS AND IMPLICATIONS

Our antimicrobial stewardship program resulted in a decrease in resistance to FLQ among urinary Enterobacteriaceae isolated from nursing home residents. The support of an AMT along with continuous training of the coordinating physician seems to be an important component to ensure efficacy of the intervention.

Carbapenem and Cephalosporin Resistance among Enterobacteriaceae in Healthcare-Associated Infections, California, USA1

We analyzed antimicrobial susceptibility test results reported in healthcare-associated infections by California hospitals during 2014-2017. Approximately 3.2% of Enterobacteriaceae reported in healthcare-associated infections were resistant to carbapenems and 26.9% were resistant to cephalosporins. The proportion of cephalosporin-resistant Escherichia coli increased 7% (risk ratio 1.07, 95% CI 1.04-1.11) per year during 2014-2017.