A multicenter analysis of trends in resistance in urinary Enterobacterales isolates from ambulatory patients in the United States: 2011-2020

Incidence and prevalence of antimicrobial resistance in outpatients with cancer: a multicentre, retrospective, cohort study

BACKGROUND

Infections are the second leading cause of death in patients with cancer and are often caused by resistant bacteria. However, the frequency of antimicrobial resistance (AMR) in outpatients with cancer is not well understood. We aimed to compare the frequency of AMR bacterial pathogens in outpatients with and without cancer.

METHODS

This retrospective cohort study evaluated antimicrobial susceptibility of bacteria isolated from adults (aged ≥18 years) with and without cancer seeking care in 198 outpatient health-care settings in the USA. Data were collected using the BD Insights Research Database. Patients who were not prescribed cancer medications or not admitted to an inpatient cancer unit in the predefined period were categorised as patients without cancer. Patients were included in the cancer cohort if they received medication solely or sometimes indicated for cancer. Data on gender and race or ethnicity were not collected. Non-duplicate and non-contaminant pathogens collected from various samples (ie, blood, intra-abdominal, respiratory, urine, skin or wound, and other) in outpatients were used to assess the coprimary outcomes: overall and source-specific proportions of non-susceptible pathogen isolates with corresponding AMR odds ratios (ORs); and rates of AMR pathogens per 1000 isolates with corresponding AMR incidence rate ratio (IRR) in patients with and without cancer.

FINDINGS

Data were collected between April 1, 2018, and Dec 31, 2022. 53 006 (3·2%) of 1 655 594 pathogens identified were from 27 421 patients with cancer and 1 602 588 (96·8%) were from 928 128 patients without cancer. For Pseudomonas aeruginosa, carbapenem non-susceptibility was higher in pathogen isolates from patients with cancer (816 [14·4%] of 5683) than patients without cancer (10 709 [11·3%] 94 419; OR 1·22 [95% CI 1·13-1·32]). For Enterobacterales, fluoroquinolone non-susceptibility was higher in pathogen isolates from patients with cancer (8662 [28·0%] of 30 867) than patients without cancer (238 479 [21·8%] of 1 095 996; OR 1·44 [1·40-1·47]), as was carbapenem non-susceptibility (472 [1·5%] of 30 867 vs 9165 [0·8%] of 1 095 996; OR 1·89 [1·72-2·07]), multidrug-resistant pathogens (2672 [8·7%] of 30 867 vs 48 962 [4·5%] of 1 095 996; OR 2·03 [1·95-2·11]), and extended-spectrum β-lactamase producers (4343 [16·5%] of 26 327 vs 93 977 [9·4%] of 996 853; OR 1·96 [1·90-2·03]). For Staphylococcus aureus, meticillin resistance was higher in pathogen isolates from patients with cancer (4747 [53·0%] of 8959) than patients without cancer (129 291 [48·3%] of 267 520; OR 1·20 [1·15-1·25]). For Enterococcus spp, vancomycin resistance was higher in pathogen isolates from patients with cancer (1329 [18·6%] of 7145) than patients without cancer (12 333 [9·1%] of 135 772]; ORR 2·20 [2·06-2·34). The rates and corresponding IRRs of AMR pathogens per 1000 isolates was also higher in patients with cancer compared with patients without cancer, particularly for carbapenem non-susceptible P aeruginosa (IRR 2·06 [1·91-2·21]) and vancomycin-resistant enterococci (IRR 3·06 [2·89-3·24]). For all comparisons, p<0·0001.

INTERPRETATION

AMR proportions and IRRs for most key pathogens were up to three-times higher in isolates from outpatients with cancer than those without cancer, highlighting the need for enhanced surveillance, infection prevention, and timely diagnostic stewardship to improve antibiotic prescribing in this population.

FUNDING

AMR Action Fund.

Exploring risk factors and antimicrobial susceptibility patterns associated with bacteriuria among Syrian refugees in makeshift camps

BACKGROUND

The health and well-being of refugees are critically compromised by harsh living conditions, which foster the emergence of infectious diseases and the misuse of antimicrobial agents. This multi-centre, cross-sectional, community-based study investigated the prevalence of urine carriage of bacteria and the associated antimicrobial resistance patterns of the isolates among Syrian refugees living in makeshift camps in Lebanon, an East Mediterranean country.

METHODS

We used multi-variable logistic regression models to identify the risk factors associated with bacteriuria in this vulnerable population. Mid-stream urine samples were collected aseptically from 79 Syrian refugees; regardless of whether they exhibited symptoms of urinary tract infections. Samples were inoculated onto UriSelect™ 4 chromogenic agar, and bacterial isolates were identified using MALDI-TOF-MS. Antibiotic susceptibility testing was assessed using the Kirby-Bauer disk diffusion assay.

FINDINGS

The prevalence of bacteriuria was 30.8% (95% confidence interval: 21.6-41.7), and the aetiologic agents were primarily Escherichia coli (80%), Klebsiella pneumoniae (12%) and Enterobacter cloacae complex (8%). The Enterobacterales isolates exhibited high resistance to penicillins (64%), cephalosporins (20-48%), and quinolones (28%), with 56% showing multi-drug resistance. While the female sex and rubbish accumulation were risk factors, tea consumption, reduced chicken intake, and economic support were protective against bacteriuria.

CONCLUSIONS

This report corroborates prior anecdotal evidence regarding underdiagnosed bacteriuria among Syrian refugees in Lebanon. The data highlight the pressing need for monitoring and awareness programmes to curb the spread of infectious diseases and antimicrobial resistance in both refugee and host communities.

AI driven decision support reduces antibiotic mismatches and inappropriate use in outpatient urinary tract infections

Urinary tract infections (UTIs) often prompt empiric outpatient antibiotic prescriptions, risking mismatches. This study evaluates the impact of "UTI Smart-Set" (UTIS), an AI-driven decision-support tool, on prescribing patterns and mismatches in a large outpatient organization. UTIS integrates machine learning forecasts of antibiotic resistance, patient data, and guidelines into a user-friendly order set for UTI management. From 6/1/2021-8/31/2022, 171,010 UTI diagnoses were recorded, with UTIS used in 75,630 cases involving antibiotic prescriptions. Overall acceptance rate of UTIS recommendations was 66.0%. Among 19,287 cases with urine cultures, antibiotic mismatch rate was significantly lower when UTIS recommendations were followed (8.9% vs. 14.2%, p < 0.0001). Among women over 18, mismatch rate was 47.5% lower, and among women over 50, 55.6% lower (p < 0.001). Additionally, an overall reduction of 80.5% in ciprofloxacin usage (6.4% vs 32.9%, p < 0.0001) was observed. UTIS improved prescribing accuracy, reduced mismatches, and minimized quinolone use, highlighting AI's potential for personalized infection management.

The incidence, clinical features and outcome of urinary tract infections in geriatric patients: A prospective longitudinal study

Objectives

This study compares the incidence, clinical features, microbial profiles, and outcomes of urinary tract infections (UTIs) in patients aged 65 years and older versus those younger than 65 years.

Methods

A longitudinal cohort of 1,123 patients was divided into Group A (≥65 years, n = 560) and Group B (<65 years, n = 563) and followed for 2 years. The study analyzed UTI incidence, clinical features, microbial profiles, and outcomes, including recurrence and antibiotic resistance.

Results

Over 2 years, Group A had a significantly higher UTI incidence (38.0%) compared with Group B (12.8%) (P <0.0001). Complete recovery was less common in Group A (44.6%) than in Group B (70.83%), whereas recurrent UTIs and antibiotic resistance were more frequent in Group A (43.5% vs 22.2%, P <0.0001 and 11.7% vs 2.78%, P = 0.0017, respectively). Escherichia coli was the most prevalent pathogen in both groups, with Klebsiella and Pseudomonas species more common in recurrent UTIs, particularly in older patients. Risk factors for recurrent UTIs included advanced age, female sex, diabetes, immunosuppression, and renal stones.

Conclusions

These findings highlight the need for age-specific UTI prevention and management strategies that account for microbial resistance patterns and higher recurrence rates in older patients, addressing clinical and microbial challenges.

Associations between neighbourhood-level median household income and outpatients' risk of antibiotic non-susceptible uropathogens in a major urban centre, USA

Introduction

Resistance to first-line antibiotics among urinary tract infections continues to rise, but how neighbourhood-level socioeconomic status impacts this risk remains unclear. We examined the effect of neighbourhood-level income on a patient's risk of having a uropathogen non-susceptible to trimethoprim/sulfamethoxazole (TMP/SMX) or nitrofurantoin.

Methods

We used electronic health record data and antibiotic susceptibility test results for urinary Escherichia coli and Klebsiella pneumoniae collected at Emory Healthcare outpatient facilities in greater Atlanta between October 2022 and September 2023. We determined patients' block group median household income (MHI) using their residential addresses and 2017-21 US census data. We performed a logistic regression with a priori risk factors using a generalized estimating equation, with subgroup analysis by organism and for patients with diabetes mellitus.

Results

We included 9325 urine E. coli and K. pneumoniae isolates from 3867 outpatients. Compared to uropathogenic E. coli, K. pneumoniae were more likely to be non-susceptible to nitrofurantoin (P < 0.001) and less likely to be non-susceptible to TMP/SMX (P < 0.001). Compared to the lowest MHI quintile, patients in the highest MHI quintile neighbourhoods had 0.78 odds of harbouring a non-susceptible uropathogen (95% CI: 0.64, 0.95) after controlling for patient age, sex and race/ethnicity, along with neighbourhood-level characteristics. This association was stronger for K. pneumoniae infections and non-significant among people with diabetes.

Conclusions

Higher neighbourhood-level MHI was associated with lower individual risk of harbouring a first-line antibiotic-non-susceptible uropathogen.

Activity of mecillinam against USA urinary tract clinical isolates from 2017 to 2020 including isolates resistant to comparator antibiotics

OBJECTIVES

To support the clinical development of mecillinam and pivmecillinam in the United States for the treatment of complicated and uncomplicated urinary tract infections (UTIs), this study investigated the activity of mecillinam compared with other antibiotics against Enterobacterales isolates from patients with UTIs in the United States during 2017 to 2020. Mecillinam is a first-in-class amidinopenicillin antibiotic, being the only β-lactam to exert its antibacterial activity through exclusive binding to penicillin-binding protein 2. Pivmecillinam is the oral prodrug of mecillinam and is recommended as a first-line therapy by the Infectious Disease Society of America guidelines for uncomplicated UTIs and is approved for the treatment of uncomplicated UTIs in Europe, Canada, and the United States.

METHODS

A total of 3303 isolates were collected and antimicrobial susceptibility determined according to Clinical Laboratory and Standards Institute (CLSI) guidelines.

RESULTS

Susceptibility was highest for fosfomycin (97.1% susceptible) and mecillinam (94.9% susceptible). Against extended-spectrum beta-lactamase (ESBL)-positive bacteria susceptibilities were highest for mecillinam (98.2% susceptible) and fosfomycin (97.3% susceptible) and against ESBL-positive K. pneumoniae only mecillinam and fosfomycin had > 80% susceptibility. Resistance to comparator antibiotics was highest for trimethoprim-sulfamethoxazole (27.1%), followed by ciprofloxacin (19.3%), ceftriaxone (19.2%), and nitrofurantoin (12.1%). Multi-drug-resistant isolates were most susceptible to mecillinam and fosfomycin.

CONCLUSION

The data further support the clinical development and clinical utility of mecillinam. © 2024 The Author(s). Published by Elsevier Ltd on behalf of International Society for Antimicrobial Chemotherapy.

Urogenital colonization and pathogenicity of E. Coli in the vaginal microbiota during pregnancy

This study explores the role of the vaginal microbiota (VM) in the pathophysiology of asymptomatic bacteriuria (ASB) in a cohort of 1,553 pregnant women. Worldwide, E. coli remains the most common etiological agent of bacteriuria during pregnancy and also a major causative agent of newborn infections. A healthy VM is typically characterized by low diversity and is dominated by lactic acid-producing species, notably those from the Lactobacillus genus. Our results point to decreases in Lactobacillus spp associated with an increase of gut-microbiota-associated species from the Enterobacterales order. Escherichia coli exhibited the most pronounced increase in abundance within the VM during bacteriuria and was notably associated with ASB. Molecular typing and antimicrobial resistance characterization of 72 metagenome assembled E. coli genomes (MAGs) from these pregnant women revealed a genomic signature of extraintestinal pathogenic E. coli ("ExPEC") strains, which are involved in various extraintestinal infections such as urinary tract infections, newborn infections and bacteremia. Microbial diversity within the vaginal samples from which an E. coli MAG was obtained showed a substantial variation, primarily marked by a decrease in abundance of Lactobacillus species. Overall, our study shows how disruption in key bacterial group within the VM can disrupt its stability, potentially leading to the colonization by opportunistic pathogens.

An Investigation Into Carbapenem Resistance in Enterobacteriaceae Among Outpatients With Urinary Tract Infection in Southwestern Uganda

Background and aim Urinary tract infections (UTIs) are among the most common bacterial infections worldwide, primarily caused by Enterobacteriaceae. The rise of carbapenem-resistant Enterobacteriaceae (CRE), complicates treatment of UTIs, yet the distribution of CRE and carbapenemase genes in Uganda's hospitals is not sufficiently explored. This study aimed to examine the distribution of carbapenemase genes in Enterobacteriaceae isolated from urinary tract infections in outpatients in southwestern Uganda. Methods A cross-sectional hospital-based study was conducted in southwestern Uganda. The study involved 111 participants who tested positive for carbapenemase genes. These participants were selected from a total of 2,371 patients presenting with urinary tract infections (UTIs) at Bwizibwera Health Center IV and Rubaya Health Center III. Enterobacteriaceaewere identified using a series of biochemical tests, and the presence of carbapenemase resistance genes (blaVIM, blaOXA-48, blaNDM, blaKPC, and blaIMP) was confirmed through polymerase chain reaction (PCR) genotyping. Data were analyzed and presented as frequencies and proportions, displayed in tables and charts. Results We screened a total of 2,371 participants with symptoms of urinary tract infections (UTI) for Enterobacteriaceae, 455 (19.2%) tested positive for at least one of the Enterobacteriaceae species. Disk susceptibility testing (DST) for carbapenems (meropenem and ertapenem) revealed a phenotypic carbapenem resistance prevalence of 5.7% (26/455), while polymerase chain reaction (PCR) identified a genotypic prevalence of 24.4% (111/455). Klebsiella spp. was the most common carbapenemase gene carrier (60/111, 54.1%), with blaIMP being the most frequent gene detected (32.4%). PCR detected more carbapenemase-producing organisms compared to DST. Notably, 14.4% of the isolates harbored multiple carbapenem resistance genes, with one sample carrying four different genes. Conclusion Our study revealed a high genotypic prevalence of CRE, especially in Klebsiella spp. and Escherichia spp. isolates with a low phenotypic expression. This suggests that relying solely on DST could miss resistant strains, emphasizing the importance of molecular diagnostics like PCR for accurate detection. Carbapenemase inhibitors should be prescribed alongside carbapenem drugs where CREs are suspected, combined with continued surveillance to help manage CRE and reduce their spread in resource-limited settings.

Draft genomes of Klebsiella aerogenes, Klebsiella huaxiensis, and Klebsiella michiganensis isolates from the urinary tract

Several Klebsiella spp. can be the cause of urinary tract infections. Here we present the draft genome assemblies for four urinary isolates of three Klebsiella spp.: Klebsiella aerogenes UMB7541, Klebsiella michiganensis UMB11142 and UMB11423, and Klebsiella huaxiensis UMB11391 to further explore the genetic diversity of Klebsiella in the urinary tract.

Bayesian estimation of the prevalence of antimicrobial resistance: a mathematical modelling study

BACKGROUND

Estimates of the prevalence of antimicrobial resistance (AMR) underpin effective antimicrobial stewardship, infection prevention and control, and optimal deployment of antimicrobial agents. Typically, the prevalence of AMR is determined from real-world antimicrobial susceptibility data that are time delimited, sparse, and often biased, potentially resulting in harmful and wasteful decision-making. Frequentist methods are resource intensive because they rely on large datasets.

OBJECTIVES

To determine whether a Bayesian approach could present a more reliable and more resource-efficient way to estimate population prevalence of AMR than traditional frequentist methods.

METHODS

Retrospectively collected, open-source, real-world pseudonymized healthcare data were used to develop a Bayesian approach for estimating the prevalence of AMR by combination with prior AMR information from a contextualized review of literature. Iterative random sampling and cross-validation were used to assess the predictive accuracy and potential resource efficiency of the Bayesian approach compared with a standard frequentist approach.

RESULTS

Bayesian estimation of AMR prevalence made fewer extreme estimation errors than a frequentist estimation approach [n = 74 (6.4%) versus n = 136 (11.8%)] and required fewer observed antimicrobial susceptibility results per pathogen on average [mean = 28.8 (SD = 22.1) versus mean = 34.4 (SD = 30.1)] to avoid any extreme estimation errors in 50 iterations of the cross-validation. The Bayesian approach was maximally effective and efficient for drug-pathogen combinations where the actual prevalence of resistance was not close to 0% or 100%.

CONCLUSIONS

Bayesian estimation of the prevalence of AMR could provide a simple, resource-efficient approach to better inform population infection management where uncertainty about AMR prevalence is high.

Likelihood of Antimicrobial Resistance in Urinary E. coli Isolates Among US Female Patients with Recurrent Versus Non-Recurrent uUTI

OBJECTIVE

To assess the relative likelihood of antimicrobial resistance (AMR) and multi-drug resistance (MDR) among E. coli isolates from outpatients with recurrent versus non-recurrent uncomplicated urinary tract infection (uUTI).

METHODS

In this retrospective observational US cohort study, female outpatients (≥12 years) with uUTI, positive E. coli culture, and treated with ≥1 oral antibiotic within ±5 days of diagnosis were grouped into recurrent and non-recurrent uUTI cohorts per their UTI history (past 12 months). AMR to specific drug classes was evaluated at index. Univariable and multivariable logistic regression models estimated the likelihood of not-susceptible E. coli isolates (AMR/MDR) among patients with recurrent uUTI versus non-recurrent uUTI.

RESULTS

Recurrent (N = 12,234) and non-recurrent (N = 68,033) uUTI cohorts had similar distributions (race, ethnicity, region). Patients with recurrent uUTI had a higher prevalence of E. coli resistance to trimethoprim-sulfamethoxazole (21.8% vs 18.7%) and fluoroquinolones (14.2% vs 8.6%), and more isolates were extended-spectrum β-lactamase-producing (5.9% vs 4.1%) compared to non-recurrent uUTI patients. Patients with recurrent uUTI had a higher likelihood (odds ratio [95% confidence interval]) of any AMR (1.28 [1.22-1.34]), single drug-class resistance (1.18 [1.12-1.24]), and resistance to 2 (1.53 [1.41-1.67]) or ≥3 drug classes (1.70 [1.48-1.96]) (all P <.001).

CONCLUSION

This study delineated the likelihood of AMR and MDR among E. coli isolates from patients with recurrent versus non-recurrent uUTI. While some treatment guidelines support empiric therapy in recurrent uUTI, the increased likelihood of resistance among these patients suggests that culture and susceptibility testing should be undertaken to inform recurrent uUTI treatment.

Review of the In Vitro Microbiological Activity of Mecillinam Against Common Uropathogens in Uncomplicated Urinary Tract Infection: Focus on Resistant Pathogens

Antimicrobial resistance in uropathogens commonly causing urinary tract infections (UTIs) is a growing problem internationally. Pivmecillinam, the oral prodrug of mecillinam, has been used for over 40 years, primarily in Northern Europe and Canada. It is recommended in several countries as a first-line agent for the treatment of uncomplicated UTIs (uUTIs) and is now approved in the United States. We performed a structured literature search to review the available evidence on susceptibility of common uUTI-causing uropathogens to mecillinam. Among 38 studies included in this literature review, susceptibility rates for Escherichia coli to mecillinam-including resistant phenotypes such as extended-spectrum β-lactamase-producing E. coli-exceed 90% in most studies. High rates of susceptibility were also reported among many other uropathogens including Klebsiella spp., Enterobacter spp., and Citrobacter spp. In the current prescribing climate within the United States, pivmecillinam represents a viable first-line treatment option for patients with uUTI.

The Diagnosis and Treatment of Adult Urinary Tract Infections in the Emergency Department

Emergency medicine has been called the art of "making complicated clinical decisions with limited information." This description is particularly relevant in the case of diagnosis and treatment of urinary tract infections (UTIs). Although common, UTIs are often challenging to diagnose given the presence of non-specific signs and symptoms and over-reliance on laboratory findings. This review provides an interdisciplinary interpretation of the primary literature and practice guidelines, with a focus on diagnostic and antimicrobial stewardship in the emergency department.

Prevalence, regional distribution, and trends of antimicrobial resistance among female outpatients with urine Klebsiella spp. isolates: a multicenter evaluation in the United States between 2011 and 2019

BACKGROUND

Antimicrobial resistance research in uncomplicated urinary tract infection typically focuses on the main causative pathogen, Escherichia coli; however, little is known about the antimicrobial resistance burden of Klebsiella species, which can also cause uncomplicated urinary tract infections. This retrospective cohort study assessed the prevalence and geographic distribution of antimicrobial resistance among Klebsiella species and antimicrobial resistance trends for K. pneumoniae in the United States (2011-2019).

METHODS

K. pneumoniae and K. oxytoca urine isolates (30-day, non-duplicate) among female outpatients (aged ≥ 12 years) with presumed uUTI at 304 centers in the United States were classified by resistance phenotype(s): not susceptible to nitrofurantoin, trimethoprim/sulfamethoxazole, or fluoroquinolone, extended-spectrum β-lactamase-positive/not susceptible; and multidrug-resistant based on ≥ 2 and ≥ 3 resistance phenotypes. Antimicrobial resistance prevalence by census division and age, as well as antimicrobial resistance trends over time for Klebsiella species, were assessed using generalized estimating equations.

RESULTS

270,552 Klebsiella species isolates were evaluated (250,719 K. pneumoniae; 19,833 K. oxytoca). The most frequent resistance phenotypes in 2019 were nitrofurantoin not susceptible (Klebsiella species: 54.0%; K. pneumoniae: 57.3%; K. oxytoca: 15.1%) and trimethoprim/sulfamethoxazole not susceptible (Klebsiella species: 10.4%; K. pneumoniae: 10.6%; K. oxytoca: 8.6%). Extended-spectrum β-lactamase-positive/not susceptible prevalence was 5.4%, 5.3%, and 6.8%, respectively. K. pneumoniae resistance phenotype prevalence varied (p < 0.0001) geographically and by age, and increased over time (except for the nitrofurantoin not susceptible phenotype, which was stable and > 50% throughout).

CONCLUSIONS

There is a high antimicrobial resistance prevalence and increasing antimicrobial resistance trends among K. pneumoniae isolates from female outpatients in the United States with presumed uncomplicated urinary tract infection. Awareness of K. pneumoniae antimicrobial resistance helps to optimize empiric uncomplicated urinary tract infection treatment.

Decreasing Antibiotic Resistance Trends Nationally in Gram-Negative Bacteria Across United States Veterans Affairs Medical Centers, 2011-2020

INTRODUCTION

Gram-negative resistance is a well-acknowledged public health threat. Surveillance data can be used to monitor resistance trends and identify strategies to mitigate their threat. The objective of this study was to assess antibiotic resistance trends in Gram-negative bacteria.

METHODS

The first cultures of Pseudomonas aeruginosa, Citrobacter, Escherichia coli, Enterobacter, Klebsiella, Morganella morganii, Proteus mirabilis, and Serratia marcescens per hospitalized patient per month collected from 125 Veterans Affairs Medical Centers (VAMCs) between 2011 to 2020 were included. Time trends of resistance phenotypes (carbapenem, fluoroquinolone, extended-spectrum cephalosporin, multi-drug, and difficult-to-treat) were analyzed with Joinpoint regression to estimate average annual percent changes (AAPC) with 95% confidence intervals and p values. A 2020 antibiogram of reported antibiotic percent susceptibilities was also created to evaluate resistance rates at the beginning of the COVID-19 pandemic.

RESULTS

Among 40 antimicrobial resistance phenotype trends assessed in 494,593 Gram-negative isolates, there were no noted increases; significant decreases were observed in 87.5% (n = 35), including in all P. aeruginosa, Citrobacter, Klebsiella, M. morganii, and S. marcescens phenotypes (p < 0.05). The largest decreases were seen in carbapenem-resistant phenotypes of P. mirabilis, Klebsiella, and M. morganii (AAPCs: - 22.9%, - 20.7%, and - 20.6%, respectively). In 2020, percent susceptibility was over 80% for all organisms tested against aminoglycosides, cefepime, ertapenem, meropenem, ceftazidime-avibactam, ceftolozane-tazobactam, and meropenem-vaborbactam.

CONCLUSION

We observed significant decreases in antibiotic resistance for P. aeruginosa and Enterobacterales over the past decade. According to the 2020 antibiogram, in vitro antimicrobial activity was observed for most treatment options. These results may be related to the robust infection control and antimicrobial stewardship programs instituted nationally among VAMCs.

Antimicrobial resistance of clinical Enterobacterales isolates from urine samples, Germany, 2016 to 2021

IntroductionEmpirical therapy for the treatment of urinary tract infections should be tailored to the current distribution and susceptibility of potential pathogens to ensure optimal treatment.AimWe aimed to provide an up-to-date overview of the epidemiology and susceptibility of Enterobacterales isolated from urine in Germany.MethodsWe retrospectively analysed antimicrobial susceptibility data from 201,152 urine specimens collected between January 2016 and June 2021 from in- and outpatients. Multiple logistic regression analysis was used to evaluate the association between year of investigation and antibiotic resistance, adjusted for age, sex and species subgroup. Subgroup analyses were performed for midstream urine samples obtained from (i) female outpatients aged 15 to 50 years, (ii) female outpatients older than 50 years and (iii) male outpatients.ResultsResistance rates of less than 20% were observed for nitroxoline (3.9%), fosfomycin (4.6%), nitrofurantoin (11.7%), cefuroxime (13.5%) and ciprofloxacin (14.2%). Resistance to trimethoprim/sulfamethoxazole (SXT) (20.1%), amoxicillin-clavulanic acid (20.5%), trimethoprim (24.2%), pivmecillinam (29.9%) and ampicillin (53.7%) was considerably higher. In the subgroup of outpatient women aged 15-50 years, resistance rates were generally lower. Resistance rates of all antibiotics decreased from 2016 to 2021. Multiple logistic regression revealed the lowest adjusted odds ratio (ORadj) of 0.838 (95% confidence interval (CI): 0.819-0.858; p < 0.001) for pivmecillinam and the highest ORadj of 0.989 (95% CI: 0.972-1.007; p = 0.226) for nitrofurantoin.ConclusionsResistance has generally decreased over the past years, independent of sex, age and causative pathogen. Our data provide an important basis for empirical antibiotic recommendations in various settings and patient collectives.

Antimicrobial Resistance in Urinary Tract Infections: Is There an Issue and Does It Matter?

Antimicrobial resistance (AMR) has increased substantially among community-acquired uropathogens that cause urinary tract infections (UTI), limiting the availability of effective oral antibiotic treatments. This review includes coverage of an expert-led Learning Lounge, symposium session, and several poster presentations, that took place between 20th–22nd October 2022 as part of IDWeek2022 in Washington, D.C., USA. An immersive Learning Lounge, sponsored by GSK, opened with Keith Kaye, Department of Medicine, Rutgers–Robert Wood Johnson Medical School, New Brunswick, New Jersey, USA, who illuminated the concerns of AMR in community-acquired UTIs, delivering contemporary surveillance data, and outlined how in vitro data may translate into practical advice. This led fittingly to Erin McCreary, Division of Infectious Diseases, Department of Medicine, University of Pittsburgh School of Medicine, Pennsylvania, USA, who enquired whether enough is being done in clinical practice regarding community-acquired infections, highlighting the importance of antimicrobial stewardship (AMS), and galvanising the audience to adapt healthcare settings to the changing landscape. The scientific programme also included three data-rich posters that showcased Kaye’s surveillance data on Escherichia coli and Klebsiella pneumoniae co-resistance, along with the geographical distribution of K. pneumoniae. An insightful poster by Claire Trennery, Value Evidence Outcomes, GSK, Brentford, UK, considered the patient perspective of UTI symptoms in defining antibiotic treatment success, and two posters presented by Rodrigo Mendes, JMI Laboratories, North Liberty, Iowa, USA, examined in vitro global surveillance data of emerging antimicrobial treatments.

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

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

Sulopenem or Ciprofloxacin for the Treatment of Uncomplicated Urinary Tract Infections in Women: A Phase 3, Randomized Trial

BACKGROUND

There are limited treatment options for uncomplicated urinary tract infection (uUTI) caused by resistant pathogens. Sulopenem etzadroxil/probenecid (sulopenem) is an oral thiopenem antibiotic active against multidrug-resistant pathogens that cause uUTIs.

METHODS

Patients with uUTI were randomized to 5 days of sulopenem or 3 days of ciprofloxacin. The primary endpoint was overall success, defined as both clinical and microbiologic response at day 12. In patients with ciprofloxacin-nonsusceptible baseline pathogens, sulopenem was compared for superiority over ciprofloxacin; in patients with ciprofloxacin-susceptible pathogens, the agents were compared for noninferiority. Using prespecified hierarchical statistical testing, the primary endpoint was tested in the combined population if either superiority or noninferiority was declared in the nonsusceptible or susceptible population, respectively.

RESULTS

In the nonsusceptible population, sulopenem was superior to ciprofloxacin, 62.6% vs 36.0% (difference, 26.6%; 95% confidence interval [CI], 15.1 to 7.4; P <.001). In the susceptible population, sulopenem was not noninferior to ciprofloxacin, 66.8% vs 78.6% (difference, -11.8%; 95% CI, -18.0 to 5.6). The difference was driven by a higher rate of asymptomatic bacteriuria (ASB) post-treatment in patients on sulopenem. In the combined analysis, sulopenem was noninferior to ciprofloxacin, 65.6% vs 67.9% (difference, -2.3%; 95% CI, -7.9 to 3.3). Diarrhea occurred more frequently with sulopenem (12.4% vs 2.5%).

CONCLUSIONS

Sulopenem was noninferior to ciprofloxacin in the treatment of uUTIs. Sulopenem was superior to ciprofloxacin in patients with uUTIs due to ciprofloxacin-nonsusceptible pathogens. Sulopenem was not noninferior in patients with ciprofloxacin-susceptible pathogens, driven largely by a lower rate of ASB in those who received ciprofloxacin.

CLINICAL TRIAL REGISTRATION

NCT03354598.

Antibiotic Resistance and Mechanisms of Pathogenic Bacteria in Tubo-Ovarian Abscess

A tubo-ovarian abscess (TOA) is a common type of inflammatory lump in clinical practice. TOA is an important, life-threatening disease, and it has become more common in recent years, posing a major health risk to women. Broad-spectrum antimicrobial agents are necessary to cover the most likely pathogens because the pathogens that cause TOA are polymicrobial. However, the response rate of antibiotic treatment is about 70%, whereas one-third of patients have poor clinical consequences and they require drainage or surgery. Rising antimicrobial resistance serves as a significant reason for the unsatisfactory medical outcomes. It is important to study the antibiotic resistance mechanism of TOA pathogens in solving the problems of multi-drug resistant strains. This paper focuses on the most common pathogenic bacteria isolated from TOA specimens and discusses the emerging trends and epidemiology of resistant Escherichia coli, Bacteroides fragilis, and gram-positive anaerobic cocci. Besides that, new methods that aim to solve the antibiotic resistance of related pathogens are discussed, such as CRISPR, nanoparticles, bacteriophages, antimicrobial peptides, and pathogen-specific monoclonal antibodies. Through this review, we hope to reveal the current situation of antibiotic resistance of common TOA pathogens, relevant mechanisms, and possible antibacterial strategies, providing references for the clinical treatment of drug-resistant pathogens.

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.

Regional Differences in Antibiotic-resistant Enterobacterales Urine Isolates in the United States: 2018-2020

Antimicrobial resistance (AMR) can complicate effective management of urinary tract infections. We conducted a retrospective study of AMR in Enterobacterales urine isolates from ambulatory and hospitalized adult patients from 2018-2020 (BD Insights Research Database) to evaluate regional differences in isolates with an extended-spectrum beta-lactamase-producing phenotype and those not susceptible to beta-lactams, fluoroquinolone (FQ), nitrofurantoin (NFT), trimethoprim/sulfamethoxazole (TMP/SMX), or multiple antibiotic classes (≥ 2 or ≥ 3). Our analyses included 349,741 Enterobacterales urine isolates from 321 inpatient facilities and 980,354 isolates from 338 ambulatory care facilities. In multivariable analyses, the highest rate of resistance was to beta-lactams (60.8% and 55.8% for inpatient and ambulatory settings, respectively), followed by FQ (27.5%), NFT (27.0%), and TMP/SMX (25.4%) for inpatients and by TMP/SMX (22.4%), FQ (21.6%), and NFT (21.6%) for ambulatory patients. Isolates with an extended-spectrum beta-lactamase-producing phenotype (13.2% and 8.6% for inpatient and ambulatory settings, respectively) and multidrug resistance (inpatient and ambulatory rates of 23.4% and 17.7% for ≥ 2 drugs; 9.9% and 6.4% for ≥ 3 drugs) were also prevalent. Statistically significant differences by geographic region (P ≤ 0.005) were observed for AMR classes in both inpatient and ambulatory settings, but the rates remained above the thresholds recommended for empiric urinary tract infection therapy across most regions.