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

Cephalosporins for Outpatient Pyelonephritis in the Emergency Department: COPY-ED Study

STUDY OBJECTIVE

The primary objective of our study was to compare the effectiveness of oral cephalosporins versus fluroquinolones and trimethoprim/sulfamethoxazole (TMP-SMX) for the treatment of pyelonephritis in patients discharged home from the emergency department (ED).

METHODS

This was a multicenter, retrospective, observational cohort study of 11 geographically diverse US EDs. Patients aged ≥18 years diagnosed with pyelonephritis and discharged home from the ED between January 1, 2021 and October 31, 2023 were included. The primary outcome was treatment failure at 14 days defined as a composite outcome of the following: (1) recurrence of urinary symptoms, (2) repeat ED visit or hospitalization for a urinary tract infection, (3) receipt of a new antibiotic prescription for urinary tract infection. Secondary outcome was appropriateness of empiric treatment based on urine culture susceptibility.

RESULTS

Among the 851 patients who met inclusion criteria, 647 patients received a cephalosporin, and 204 patients received an Infectious Diseases Society of America guideline-endorsed first-line treatment (fluroquinolones, TMP-SMX). Overall, baseline characteristics were similar between the 2 cohorts. Rates of treatment failure were not significantly different in the cephalosporin group compared with the fluroquinolone/TMP-SMX groups (17.2% of cephalosporin vs 22.5% of fluroquinolone/TMP-SMX group, difference=5.3%, 95% confidence interval -0.118 to 0.01). After adjusting for potential confounders, cephalosporin use was not associated with treatment failure (odds ratio=0.22, 95% confidence interval 0.03 to 1.95). There was no difference in rates of appropriate empiric treatment based on urine culture susceptibility.

CONCLUSION

Oral cephalosporins were associated with similar treatment failure rates compared with Infectious Diseases Society of America guideline-endorsed treatments for the treatment of pyelonephritis in ED patients discharged home.

Management of Bacteriuria and Urinary Tract Infections in the Older Adult

Urinary tract infection (UTI) is one of the most frequent bacterial infections diagnosed in older adults and the most common reason for antibiotic prescriptions in nursing homes. Distinguishing between asymptomatic bacteriuria and UTI in older adults can be challenging and implementing a systematic approach to diagnosis using standard toolkits or algorithms is recommended for patients residing in post-acute and long-term care settings. This article reviews the pathophysiology, microbiology, diagnostic approach, treatment, and approaches to prophylaxis in the older adult.

Predicting antibiotic resistance in Enterobacterales to support optimal empiric treatment of urinary tract infections in outpatient veterans

Objective

Bacterial resistance is known to diminish the effectiveness of antibiotics for treatment of urinary tract infections. Review of recent healthcare and antibiotic exposures, as well as prior culture results is recommended to aid in selection of empirical treatment. However, the optimal approach for assessing these data is unclear. We utilized data from the Veterans Health Administration to evaluate relationships between culture and treatment history and the subsequent probability of antibiotic-resistant bacteria identified in urine cultures to further guide clinicians in understanding these risk factors.

Methods

Using the XGBoost algorithm, a retrospective cohort of outpatients with urine culture results and antibiotic prescriptions from 2017 to 2022 was used to develop models for predicting antibiotic resistance for three classes of antibiotics: cephalosporins, fluoroquinolones, and trimethoprim/sulfamethoxazole (TMP/SMX) obtained from urine cultures. Model performance was assessed using Area Under the Receiver Operating Characteristic curve (AUC) and Precision-Recall AUC (PRAUC).

Results

There were 392,647 prior urine cultures identified in 214,656 patients. A history of bacterial resistance to the specific treatment was the most important predictor of subsequent resistance for positive cultures, followed by a history of specific antibiotic exposure. The models performed better than previously established risk factors alone, especially for fluoroquinolone resistance, with an AUC of .84 and PRAUC of .70. Notably, the models' performance improved markedly (AUC = .90, PRAUC = .87) when applied to cultures from patients with a known history of resistance to any of the antibiotic classes.

Conclusion

These predictive models demonstrate potential in guiding antibiotic prescription and improving infection management.

Cefiderocol for treating severe aerobic Gram-negative bacterial infections: technology evaluation to inform a novel subscription-style payment model

Background

To limit the use of antimicrobials without disincentivising the development of novel antimicrobials, there is interest in establishing innovative models that fund antimicrobials based on an evaluation of their value as opposed to the volumes used. The aim of this project was to evaluate the population-level health benefit of cefiderocol in the NHS in England, for the treatment of severe aerobic Gram-negative bacterial infections when used within its licensed indications. The results were used to inform the National Institute for Health and Care Excellence guidance in support of commercial discussions regarding contract value between the manufacturer and NHS England.

Methods

The health benefit of cefiderocol was first derived for a series of high-value clinical scenarios. These represented uses that were expected to have a significant impact on patients' mortality risks and health-related quality of life. The clinical effectiveness of cefiderocol relative to its comparators was estimated by synthesising evidence on susceptibility of the pathogens of interest to the antimicrobials in a network meta-analysis. Patient-level costs and health outcomes of cefiderocol under various usage scenarios compared with alternative management strategies were quantified using decision modelling. Results were reported as incremental net health effects expressed in quality-adjusted life-years, which were scaled to 20-year population values using infection number forecasts based on data from Public Health England. The outcomes estimated for the high-value clinical scenarios were extrapolated to other expected uses for cefiderocol.

Results

Among Enterobacterales isolates with the metallo-beta-lactamase resistance mechanism, the base-case network meta-analysis found that cefiderocol was associated with a lower susceptibility relative to colistin (odds ratio 0.32, 95% credible intervals 0.04 to 2.47), but the result was not statistically significant. The other treatments were also associated with lower susceptibility than colistin, but the results were not statistically significant. In the metallo-beta-lactamase Pseudomonas aeruginosa base-case network meta-analysis, cefiderocol was associated with a lower susceptibility relative to colistin (odds ratio 0.44, 95% credible intervals 0.03 to 3.94), but the result was not statistically significant. The other treatments were associated with no susceptibility. In the base case, patient-level benefit of cefiderocol was between 0.02 and 0.15 quality-adjusted life-years, depending on the site of infection, the pathogen and the usage scenario. There was a high degree of uncertainty surrounding the benefits of cefiderocol across all subgroups. There was substantial uncertainty in the number of infections that are suitable for treatment with cefiderocol, so population-level results are presented for a range of scenarios for the current infection numbers, the expected increases in infections over time and rates of emergence of resistance. The population-level benefits varied substantially across the base-case scenarios, from 896 to 3559 quality-adjusted life-years over 20 years.

Conclusion

This work has provided quantitative estimates of the value of cefiderocol within its areas of expected usage within the NHS.

Limitations

Given existing evidence, the estimates of the value of cefiderocol are highly uncertain.

Future work

Future evaluations of antimicrobials would benefit from improvements to NHS data linkages; research to support appropriate synthesis of susceptibility studies; and application of routine data and decision modelling to assess enablement value.

Study registration

No registration of this study was undertaken.

Funding

This award was funded by the National Institute for Health and Care Research (NIHR) Health Technology Assessment Policy Research Programme (NIHR award ref: NIHR135591), conducted through the Policy Research Unit in Economic Methods of Evaluation in Health and Social Care Interventions, PR-PRU-1217-20401, and is published in full in Health Technology Assessment; Vol. 28, No. 28. See the NIHR Funding and Awards website for further award information.

Identifying signs and symptoms of urinary tract infection from emergency department clinical notes using large language models

BACKGROUND

Natural language processing (NLP) tools including recently developed large language models (LLMs) have myriad potential applications in medical care and research, including the efficient labeling and classification of unstructured text such as electronic health record (EHR) notes. This opens the door to large-scale projects that rely on variables that are not typically recorded in a structured form, such as patient signs and symptoms.

OBJECTIVES

This study is designed to acquaint the emergency medicine research community with the foundational elements of NLP, highlighting essential terminology, annotation methodologies, and the intricacies involved in training and evaluating NLP models. Symptom characterization is critical to urinary tract infection (UTI) diagnosis, but identification of symptoms from the EHR has historically been challenging, limiting large-scale research, public health surveillance, and EHR-based clinical decision support. We therefore developed and compared two NLP models to identify UTI symptoms from unstructured emergency department (ED) notes.

METHODS

The study population consisted of patients aged ≥ 18 who presented to an ED in a northeastern U.S. health system between June 2013 and August 2021 and had a urinalysis performed. We annotated a random subset of 1250 ED clinician notes from these visits for a list of 17 UTI symptoms. We then developed two task-specific LLMs to perform the task of named entity recognition: a convolutional neural network-based model (SpaCy) and a transformer-based model designed to process longer documents (Clinical Longformer). Models were trained on 1000 notes and tested on a holdout set of 250 notes. We compared model performance (precision, recall, F1 measure) at identifying the presence or absence of UTI symptoms at the note level.

RESULTS

A total of 8135 entities were identified in 1250 notes; 83.6% of notes included at least one entity. Overall F1 measure for note-level symptom identification weighted by entity frequency was 0.84 for the SpaCy model and 0.88 for the Longformer model. F1 measure for identifying presence or absence of any UTI symptom in a clinical note was 0.96 (232/250 correctly classified) for the SpaCy model and 0.98 (240/250 correctly classified) for the Longformer model.

CONCLUSIONS

The study demonstrated the utility of LLMs and transformer-based models in particular for extracting UTI symptoms from unstructured ED clinical notes; models were highly accurate for detecting the presence or absence of any UTI symptom on the note level, with variable performance for individual symptoms.

Laboratory Tests, Bacterial Resistance, and Treatment Options in Adult Patients Hospitalized with a Suspected Urinary Tract Infection

Patients treated for systemic urinary tract infections commonly have nonspecific presentations, and the specificity of the results of the urinalysis and urine cultures is low. In the following narrative review, we will describe the widespread misuse of urine testing, and consider how to limit testing, the disutility of urine cultures, and the use of antibiotics in hospitalized adult patients. Automated dipstick testing is more precise and sensitive than the microscopic urinalysis which will result in false negative test results if ordered to confirm a positive dipstick test result. There is evidence that canceling urine cultures if the dipstick is negative (negative leukocyte esterase, and nitrite) is safe and helps prevent the overuse of urine cultures. Because of the side effects of introducing a urine catheter, for patients who cannot provide a urine sample, empiric antibiotic treatment should be considered as an alternative to culturing the urine if a trial of withholding antibiotic therapy is not an option. Treatment options that will decrease both narrower and wider spectrum antibiotic use include a period of watching and waiting before antibiotic therapy and empiric treatment with antibiotics that have resistance rates > 10%. Further studies are warranted to show the option that maximizes patient comfort and safety.

The Impact of Urinary Catheterization on the Antibiotic Susceptibility of ESBL-Producing Enterobacterales: A Challenging Duo

INTRODUCTION

Antimicrobial resistance (AMR) is currently a growing concern among healthcare providers, underscoring the importance of describing the regional susceptibility profile for common microorganisms that are associated with urinary tract infections (UTIs). This knowledge serves as the foundation for proper empirical therapeutic recommendations tailored to local susceptibility patterns.

RESULTS

We found a high prevalence of ESBL-producing strains (36.9%), with Escherichia coli and Klebsiella spp. being the most prevalent isolated bacteria. Among the catheterized patients, Klebsiella spp. emerged as the primary etiology, with a significant correlation between catheterization and Proteus spp. (p = 0.02) and Providencia stuartii (p < 0.0001). We observed significant correlations between urinary catheterization and older age (68.9 ± 13.7 years vs. 64.2 ± 18.1 years in non-catheterized patients, p = 0.026) and with the presence of an isolate with extensive drug resistance (p < 0.0001) or even pandrug resistance (p < 0.0001). Susceptibility rates significantly decreased for almost all the tested antibiotics during the study period. Notably, susceptibility was markedly lower among catheterized patients, with the most pronounced differences observed for carbapenems (59.6% versus 83.4%, p < 0.0001) and aminoglycosides (37.1% versus 46.9%, p = 0.0001).

MATERIALS AND METHODS

We conducted a retrospective study analyzing the susceptibility profiles of 724 extended-spectrum beta-lactamases (ESBL)-producing Enterobacterales isolated from urine cultures. Our focus was on highlighting susceptibility profiles among isolates associated with urinary catheterization and assessing the shifts in the susceptibility rates over time.

CONCLUSIONS

The constant rise in AMR rates among Enterobacterales presents significant challenges in treating severe infections, particularly among urinary catheterized patients. This trend leaves clinicians with limited or no effective treatment options. Consequently, the development and implementation of personalized treatment protocols are imperative to ensure efficient empirical therapies.

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.

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.

Evaluation of Oral Amoxicillin/Clavulanate for Urinary Tract Infections Caused by Ceftriaxone Non-Susceptible Enterobacterales

Urinary tract infections (UTIs) are one of the most common infections and are frequently caused by Gram-negative organisms. The rise of resistant isolates has prompted evaluation of alternative therapies, including amoxicillin-clavulanate which has potent activity against Ambler class A enzymes. This study sought to evaluate clinical outcomes of patients with ceftriaxone non-susceptible UTIs receiving amoxicillin-clavulanate or standard of care (SOC). This was a single-center, retrospective, cohort study of adult patients with urinary tract infections caused by a ceftriaxone non-susceptible pathogen who received amoxicillin-clavulanate or SOC. The primary outcome was clinical failure at 90 days. Secondary outcomes included time to failure, isolation of a resistant organism, and hospital length of stay. Fifty-nine patients met study inclusion: 26 received amoxicillin/clavulanate and 33 received SOC. Amoxicillin-clavulanate recipients did not have higher failure rates compared to SOC recipients. For patients requiring hospital admission, hospital length of stay was numerically shorter with amoxicillin-clavulanate. The frequency of amoxicillin-clavulanate and carbapenem-resistant organisms did not differ significantly between groups. Amoxicillin-clavulanate may be a useful alternative therapy for the treatment of ceftriaxone non-susceptible Enterobacterales UTIs.

Design of a panel of indicators for antibiotic stewardship programs in the Emergency Department

OBJECTIVE

To develop a panel of indicators to monitor antimicrobial stewardship programs activity in the emergency department.

METHODS

A multidisciplinary group consisting of experts in the management of infection in emergency departments and the implementation of antimicrobial stewardship programs (ASP) evaluated a proposal of indicators using a modified Delphi methodology. In the first round, each expert classified the relevance of each proposed indicators in two dimensions (healthcare impact and ease of implementation) and two attributes (prioritization level and frequency). The second round was conducted based on the modified questionnaire according to the suggestions raised and new indicators suggested. Experts modified the prioritization order and rated the new indicators in the same manner as in the first round.

RESULTS

61 potential indicators divided into four groups were proposed: consumption indicators, microbiological indicators, process indicators, and outcome indicators. After analyzing the scores and comments from the first round, 31 indicators were classified as high priority, 25 as intermediate priority, and 5 as low priority. Moreover, 18 new indicators were generated. Following the second round, all 61 initially proposed indicators were retained, and 18 new indicators were incorporated: 11 classified as high priority, 3 as intermediate priority, and 4 as low priority.

CONCLUSIONS

The experts agreed on a panel of ASP indicators adapted to the emergency services prioritized by level of relevance. This is as a helpful tool for the development of these programs and will contribute to monitoring the appropriateness of the use of antimicrobials in these units.

[Translated article] Design of a panel of indicators for antibiotic stewardship programs in the Emergency Department

OBJECTIVE

To develop a panel of indicators to monitor antimicrobial stewardship programs activity in the emergency department.

METHODS

A multidisciplinary group consisting of experts in the management of infection in emergency departments and the implementation of antimicrobial stewardship programs (ASP) evaluated a proposal of indicators using a modified Delphi methodology. In the first round, each expert classified the relevance of each proposed indicators in two dimensions (healthcare impact and ease of implementation) and two attributes (prioritisation level and frequency). The second round was conducted based on the modified questionnaire according to the suggestions raised and new indicators suggested. Experts modified the prioritisation order and rated the new indicators in the same manner as in the first round.

RESULTS

61 potential indicators divided into four groups were proposed: consumption indicators, microbiological indicators, process indicators, and outcome indicators. After analysing the scores and comments from the first round, 31 indicators were classified as high priority, 25 as intermediate priority, and 5 as low priority. Moreover, 18 new indicators were generated. Following the second round, all 61 initially proposed indicators were retained, and 18 new indicators were incorporated: 11 classified as high priority, 3 as intermediate priority, and 4 as low priority.

CONCLUSIONS

The experts agreed on a panel of ASP Indicators adapted to the emergency services prioritised by level of relevance. This is as a helpful tool for the development of these programs and will contribute to monitoring the appropriateness of the use of antimicrobials in these units.

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.

Global prevalence of cefiderocol non-susceptibility in Enterobacterales, Pseudomonas aeruginosa, Acinetobacter baumannii, and Stenotrophomonas maltophilia: a systematic review and meta-analysis

BACKGROUND

Cefiderocol is a last resort option for carbapenem-resistant (CR) Gram-negative bacteria, especially metallo-β-lactamase-producing Pseudomonas aeruginosa and CR Acinetobacter baumannii. Monitoring global levels of cefiderocol non-susceptibility (CFDC-NS) is important.

OBJECTIVES

To systematically collate and examine studies investigating in vitro CFDC-NS and estimate the global prevalence of CFDC-NS against major Gram-negative pathogens.

DATA SOURCES

PubMed and Scopus, up to May 2023.

STUDY ELIGIBILITY CRITERIA

Eligible were studies reporting CFDC-NS in Enterobacterales, P. aeruginosa, A. baumannii, or Stenotrophomonas maltophilia clinical isolates.

RISK-OF-BIAS ASSESSMENT

Two independent reviewers extracted study data and assessed the risk of bias on the population, setting, and measurement (susceptibility testing) domains.

DATA SYNTHESIS

Binomial-Normal mixed-effects models were applied to estimate CFDC-NS prevalence by species, coresistance phenotype, and breakpoint definition (EUCAST, CLSI, and FDA). Sources of heterogeneity were investigated by subgroup and meta-regression analyses.

RESULTS

In all, 78 studies reporting 82 035 clinical isolates were analysed (87% published between 2020 and 2023). CFDC-NS prevalence (EUCAST breakpoints) was low overall but varied by species (S. maltophilia 0.4% [95% CI 0.2-0.7%], Enterobacterales 3.0% [95% CI 1.5-6.0%], P. aeruginosa 1.4% [95% CI 0.5-4.0%]) and was highest for A. baumannii (8.8%, 95% CI 4.9-15.2%). CFDC-NS was much higher in CR Enterobacterales (12.4%, 95% CI 7.3-20.0%) and CR A. baumannii (13.2%, 95% CI 7.8-21.5%), but relatively low for CR P. aeruginosa (3.5%, 95% CI 1.6-7.8%). CFDC-NS was exceedingly high in New Delhi metallo-β-lactamase-producing Enterobacterales (38.8%, 95% CI 22.6-58.0%), New Delhi metallo-β-lactamase-producing A. baumannii (44.7%, 95% CI 34.5-55.4%), and ceftazidime/avibactam-resistant Enterobacterales (36.6%, 95% CI 22.7-53.1%). CFDC-NS varied considerably with breakpoint definition, predominantly among CR bacteria. Additional sources of heterogeneity were single-centre investigations and geographical regions.

CONCLUSIONS

CFDC-NS prevalence is low overall, but alarmingly high for specific CR phenotypes circulating in some institutions or regions. Continuous surveillance and updating of global CFDC-NS estimates are imperative while cefiderocol is increasingly introduced into clinical practice. The need to harmonize EUCAST and CLSI breakpoints was evident.

Evaluation of Extended-Spectrum Beta-Lactamase Resistance in Uropathogenic Escherichia coli Isolates from Urinary Tract Infection Patients in Al-Baha, Saudi Arabia

Urinary tract infections (UTIs) caused by extended-spectrum beta-lactamase (ESBL)-producing organisms are prevalent in both outpatient and inpatient settings, representing the most often encountered forms of infection. This research aimed to estimate the prevalence of ESBL-UTIs along with other uropathogens in the adult population and to assess the antibiotic activity against Escherichia coli extended-spectrum beta-lactamase (E. coli ESBL) isolates from patient samples in Al-Baha. A retrospective cross-sectional study included patients who presented to King Fahad Hospital in Al-Baha with clinical suspicion of UTI between 1 January 2019 and 30 September 2022. A total of 4406 urine samples with significant microbial growth were included in the scope of this investigation. A collective count of 1644 incidents of Escherichia coli (E. coli) was observed, wherein E. coli constituted 85% of the cases, while the remaining 15% comprised E. coli ESBL producers. The prevalence of E. coli ESBL was observed to be 64.7% in females and 35.3% in males, with a majority (67%) of the affected individuals being over the age of 50. The incidence of E. coli infections in the outpatient setting was found to be greater than that observed in the inpatient setting. E. coli ESBL were sensitive to colistin, tigecycline, amikacin, meropenem, imipenem, and nitrofurantoin by 100% and 93.3-100%, 95-99.6%, 95-99.06%, and 81-91%, respectively. On the other hand, the most resistant agents for E. coli ESBL were the group of cephalosporins, aztreonam, and ampicillin with 100% resistance, ciprofloxacin with 56-74% resistance, and cotrimoxazole with a 45-53% resistance level. ESBL-resistant E. coli strains are moderately prevalent in community- and hospital-acquired UTIs, especially in females and elderly patients (>50 years).

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.

Infections in Children with Cancer Admitted in an Oncology Reference Hospital: A Cross-sectional Study

Pediatric oncology patients are usually immunosuppressed due to factors such as the neoplasm and its treatment, making them more susceptible to infections. This article aims to determine the infection profile of pediatric oncology patients admitted to an oncology reference hospital in Natal, Rio Grande do Norte, Brazil. A retrospective and cross-sectional study was conducted, collecting data from patients hospitalized due to infection in a pediatric oncology unit exclusively for the Brazilian public health system, spanning from 2018 to 2021. A total of 168 episodes of infections were identified in 96 patients, resulting in 157 hospitalizations. Among the patients with infections, 62.4% had hematological malignancies, and out of these cases, 74.6% specifically had Acute Lymphoid Leukemia. The Escherichia coli (31.9%) was the most prevalent microorganism isolated from the samples. Multidrug-resistant microorganisms accounted for 52% of all identified microorganisms. Fluoroquinolones and beta-lactam were the most prevalent antibiotic classes in the analyzed antibiograms. Factors such as Sex, type of cancer, chemotherapy in the last 30 days, were found to be associated with the occurrence of infection (p < 0.05). Conducting epidemiological studies regarding infections in pediatric oncology is crucial to development of empirical protocols, and the implementation of strategies to better control future infections.

Clinical Risk Scores to Predict Nonsusceptibility to Trimethoprim-Sulfamethoxazole, Fluoroquinolone, Nitrofurantoin, and Third-Generation Cephalosporin Among Adult Outpatient Episodes of Complicated Urinary Tract Infection

Background

Clinical risk scores were developed to estimate the risk of adult outpatients having a complicated urinary tract infection (cUTI) that was nonsusceptible to trimethoprim-sulfamethoxazole (TMP-SMX), fluoroquinolone, nitrofurantoin, or third-generation cephalosporin (3-GC) based on variables available on clinical presentation.

Methods

A retrospective cohort study (1 December 2017-31 December 2020) was performed among adult members of Kaiser Permanente Southern California with an outpatient cUTI. Separate risk scores were developed for TMP-SMX, fluoroquinolone, nitrofurantoin, and 3-GC. The models were translated into risk scores to quantify the likelihood of nonsusceptibility based on the presence of final model covariates in a given cUTI outpatient.

Results

A total of 30 450 cUTIs (26 326 patients) met the study criteria. Rates of nonsusceptibility to TMP-SMX, fluoroquinolone, nitrofurantoin, and 3-GC were 37%, 20%, 27%, and 24%, respectively. Receipt of prior antibiotics was the most important predictor across all models. The risk of nonsusceptibility in the TMP-SMX model exceeded 20% in the absence of any risk factors, suggesting that empiric use of TMP-SMX may not be advisable. For fluoroquinolone, nitrofurantoin, and 3-GC, clinical risk scores of 10, 7, and 11 predicted a ≥20% estimated probability of nonsusceptibility in the models that included cumulative number of prior antibiotics at model entry. This finding suggests that caution should be used when considering these agents empirically in patients who have several risk factors present in a given model at presentation.

Conclusions

We developed high-performing parsimonious risk scores to facilitate empiric treatment selection for adult outpatients with cUTIs in the critical period between infection presentation and availability of susceptibility results.

Risk Factors and the Impact of Multidrug-Resistant Bacteria on Community-Acquired Urinary Sepsis

Risk factors for multidrug-resistant bacteria (MDRB) in nosocomial urinary tract infection (UTI) have been widely studied. However, these risk factors have not been analyzed in community-acquired urinary sepsis (US), nor have its outcomes been studied. The aim of our study is to determine risk factors for MDRB in community-acquired US and its influence on outcomes. Prospective observational study of patients with community-acquired US admitted to a university hospital. We compared epidemiological and clinical variables and outcomes of US due to MDRB and non-MDRB. Independent risk factors for MDRB were analyzed using logistic regression. A total of 193 patients were included, 33.7% of them with US due to MDRB. The median age of patients was 82 years. Hospital mortality was 17.6%, with no difference between the MDRB and non-MDRB groups. The length of hospital stay was 5 (4-8) days, with a non-significant tendency to longer hospital stays in the MDRB group (6 (4-10) vs. 5 (4-8) days, p = 0.051). Healthcare-associated US was found to be an independent risk factor for MDR bacteria by multivariate analysis. In conclusion, the impact of MDR bacteria on the outcomes of community-acquired urinary sepsis was mild. Healthcare-associated US was an independent risk factor for MDR bacteria.

PREDICTION OF MULTIDRUG-RESISTANT BACTERIA IN URINARY TRACT INFECTIONS IN THE EMERGENCY DEPARTMENT

BACKGROUND

Urinary tract infections (UTI) due to multidrug-resistant bacteria are a frequent reason for visiting the emergency department (ED).

OBJECTIVES

The aim of this study was to evaluate the applicability of a predictive model of infection by multidrug-resistant microorganisms in UTIs treated in an ED.

METHODS

This is a retrospective observational study. Adult patients admitted to an ED with a diagnosis of UTI and positive urine culture were included. The main objective was to evaluate the area under the curve of the receiver operating characteristic (AUC-ROC), the scale proposed by González-del-Castillo, considering infection by a resistant pathogen as the dependent variable and the scale score of the predictive model used as the independent variable.

RESULTS

The study included 414 patients with UTIs, 125 (30.2%) of which were caused by multidrug-resistant microorganisms. A total of 38.4% of patients were treated with antibiotics during the previous 3 months and a multidrug-resistant pathogen was isolated from 10.4% of the total during the previous 6 months. The AUC-ROC of the scale for predicting UTIs due to multidrug-resistant microorganisms was 0.79 (95% confidence interval 0.76-0.83), the optimal cut-off point being 9 points, with a sensitivity of 76.8% and a specificity of 71.6%.

CONCLUSIONS

The use of the predictive model evaluated is a useful tool in real clinical practice to improve the success of empirical treatment of patients presenting to the ED with a diagnosis of UTI and positive urine culture pending identification.

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.

Genetic Predictive Factors for Nonsusceptible Phenotypes and Multidrug Resistance in Expanded-Spectrum Cephalosporin-Resistant Uropathogenic Escherichia coli from a Multicenter Cohort: Insights into the Phenotypic and Genetic Basis of Coresistance

Antimicrobial resistance in urinary tract infections (UTIs) is a major public health concern. This study aims to characterize the phenotypic and genetic basis of multidrug resistance (MDR) among expanded-spectrum cephalosporin-resistant (ESCR) uropathogenic Escherichia coli (UPEC) causing UTIs in California patient populations. Between February and October 2019, 577 ESCR UPEC isolates were collected from patients at 6 clinical laboratory sites across California. Lineage and antibiotic resistance genes were determined by analysis of whole-genome sequence data. The lineages ST131, ST1193, ST648, and ST69 were predominant, representing 46%, 5.5%, 4.5%, and 4.5% of the collection, respectively. Overall, 527 (91%) isolates had an expanded-spectrum β-lactamase (ESBL) phenotype, with bla_CTX-M-15, bla_CTX-M-27, bla_CTX-M-55, and bla_CTX-M-14 being the most prevalent ESBL genes. In the 50 non-ESBL phenotype isolates, 40 (62%) contained bla_CMY-2, which was the predominant plasmid-mediated AmpC (pAmpC) gene. Narrow-spectrum β-lactamases, bla_TEM-1B and bla_OXA-1, were also found in 44.9% and 32.1% of isolates, respectively. Among ESCR UPEC isolates, isolates with an ESBL phenotype had a 1.7-times-greater likelihood of being MDR than non-ESBL phenotype isolates (P < 0.001). The cooccurrence of bla_CTX-M-15, bla_OXA-1, and aac(6')-Ib-cr within ESCR UPEC isolates was strongly correlated. Cooccurrence of bla_CTX-M-15, bla_OXA-1, and aac(6')-Ib-cr was associated with an increased risk of nonsusceptibility to piperacillin-tazobactam, cefepime, fluoroquinolones, and amikacin as well as MDR. Multivariate regression revealed the presence of bla_CTX-M-55, bla_TEM-1B, and the ST131 genotype as predictors of MDR. IMPORTANCE The rising incidence of resistance to expanded-spectrum cephalosporins among Escherichia coli strains, the most common cause of UTIs, is threatening our ability to successfully empirically treat these infections. ESCR E. coli strains are often MDR; therefore, UTI caused by these organisms often leads to treatment failure, increased length of hospital stay, and severe complications (D. G. Mark, Y.-Y. Hung, Z. Salim, N. J. Tarlton, et al., Ann Emerg Med 78:357-369, 2021, https://doi.org/10.1016/j.annemergmed.2021.01.003). Here, we performed an in-depth analysis of genetic factors of ESCR E. coli associated with coresistance and MDR. Such knowledge is critical to advance UTI diagnosis, treatment, and antibiotic stewardship.

Outpatient treatment and clinical outcomes of bacteriuria in veterans: A retrospective cohort analysis

OBJECTIVE

To conduct a contemporary detailed assessment of outpatient antibiotic prescribing and outcomes for positive urine cultures in a mixed-sex cohort.

DESIGN

Multicenter retrospective cohort review.

SETTING

The study was conducted using data from 31 Veterans' Affairs medical centers.

PATIENTS

Outpatient adults with positive urine cultures.

METHODS

From 2016 to 2019, data were extracted through a nationwide database and manual chart review. Positive urine cultures were reviewed at the chart, clinician, and aggregate levels. Cases were classified as cystitis, pyelonephritis, or asymptomatic bacteriuria (ASB) based upon documented signs and symptoms. Preferred therapy definitions were applied for subdiagnoses: ASB (no antibiotics), cystitis (trimethoprim-sulfamethoxazole, nitrofurantoin, β-lactams), and pyelonephritis (trimethoprim-sulfamethoxazole, fluoroquinolone). Outcomes included 30-day clinical failure or hospitalization. Odds ratios for outcomes between treatments were estimated using logistic regression.

RESULTS

Of 3,255 cases reviewed, ASB was identified in 1,628 cases (50%), cystitis was identified in 1,156 cases (36%), and pyelonephritis was identified in 471 cases (15%). Of all 2,831 cases, 1,298 (46%) received preferred therapy selection and duration for cases where it could be defined. The most common antibiotic class prescribed was a fluoroquinolone (34%). Patients prescribed preferred therapy had lower odds of clinical failure: preferred (8%) versus nonpreferred (10%) (unadjusted OR, 0.74; 95% confidence interval [CI], 0.58-0.95; P = .018). They also had lower odds of 30-day hospitalization: preferred therapy (3%) versus nonpreferred therapy (5%) (unadjusted OR, 0.55; 95% CI, 0.37-0.81; P = .002). Odds of clinical treatment failure or hospitalization was higher for β-lactams relative to ciprofloxacin (unadjusted OR, 1.89; 95% CI, 1.23-2.90; P = .002).

CONCLUSIONS

Clinicians prescribed preferred therapy 46% of the time. Those prescribed preferred therapy had lower odds of clinical failure and of being hospitalized.

Sheep and goat milk in Jordan is a reservoir of multidrug resistant extended spectrum and AmpC beta-lactamases Escherichia coli

Limited data is available on the prevalence and antimicrobial resistance of extended spectrum (ESBL) and AmpC β-lactamases Escherichia coli in sheep and goats in Jordan. This study determined the molecular prevalence and antimicrobial-resistance of ESBL and AmpC β-lactamases E. coli in 155 sheep and goat flocks across Jordan by testing 948 milk samples. The samples were enriched in MacConkey broth, and then plated on MacConkey agar with cefotaxime. The presence of ESBL and AmpC genes in the E. coli isolates was determined by PCR and the resistance toward critically important antimicrobials was tested by disc diffusion. In total, 1016 E. coli isolates were isolated from the cefotaxime supplemented MacConkey, 382 isolates harbored ESBL genes and 54 harbored bla_CMY. The prevalence of bla_CTX-M, bla_TEM, bla_CMY and bla_SHVE. coli in the milk samples were 33.5 %, 31.7 %, 5.7 %. and 1.1 %, respectively. At the flock level, 30.3 % flocks had β-lactamase E. coli, specifically 25.2 %, 20.7 %, 5.2 % and 2.6 % had bla_CTX-M, bla_TEM, bla_CMY and blaSHV E. coli, respectively. About 52.2 % of the isolates harbored both bla_CTX-M and bla_TEM. A high percentage (>59 %) of ESBL and AmpC β-lactamases E. coli resisted sulfamethoxazole/trimethoprim, tetracycline and nalidixic acid. Overall, 93.5 % and 96.3 % of ESBL and AmpC E. coli were resistant to ≥1 another antimicrobial class and 44.5 % and 44.4 % were resistant to ≥3 another antimicrobial class, respectively. This study shows that sheep and goat milk is a reservoir of multidrug resistant ESBL and AmpC β-lactamases E. coli, thus good hygienic practices and judicious antimicrobials use are important in small ruminants' farming.

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.

The immune responses to different Uropathogens call individual interventions for bladder infection

Urinary tract infection (UTI) caused by uropathogens is the most common infectious disease and significantly affects all aspects of the quality of life of the patients. However, uropathogens are increasingly becoming antibiotic-resistant, which threatens the only effective treatment option available-antibiotic, resulting in higher medical costs, prolonged hospital stays, and increased mortality. Currently, people are turning their attention to the immune responses, hoping to find effective immunotherapeutic interventions which can be alternatives to the overuse of antibiotic drugs. Bladder infections are caused by the main nine uropathogens and the bladder executes different immune responses depending on the type of uropathogens. It is essential to understand the immune responses to diverse uropathogens in bladder infection for guiding the design and development of immunotherapeutic interventions. This review firstly sorts out and comparatively analyzes the immune responses to the main nine uropathogens in bladder infection, and summarizes their similarities and differences. Based on these immune responses, we innovatively propose that different microbial bladder infections should adopt corresponding immunomodulatory interventions, and the same immunomodulatory intervention can also be applied to diverse microbial infections if they share the same effective therapeutic targets.

Urinary tract virulence genes in extended-spectrum beta-lactamase E. coli from dairy cows, beef cattle, and small ruminants

Extended-spectrum β-lactamase Escherichia coli is an important cause of urinary tract infections in humans. ESBL producers E. coli were reported in food-producing animals, but no previous study reported the virulence potential of these isolates. Thus, this study determined the virulence potential of ESBL producers E. coli isolates from 518 beef feces, 610 dairy cow feces, 305 dairy cow milk, 503 sheep milk and 445 goat milk samples. A total of 278 isolates; specifically, 130 from beef feces, 39 from the cow's feces, 42 from cow's milk, 44 from sheep milk and 23 from goats' milk were isolated and then tested for 14 virulence genes by polymerase chain reaction. After that, the correlation of virulence genes presence among the isolates was determined statistically. Overall, 97% of the isolates carried fimH, 39% carried iroN _{E. coli} and 32% carried papC. The kpsMT K1, cnf1, papAH, papG allele II & III, papG allele II, and kpsMT II were carried by 6 to 23% of the isolates, while less than 6% of the isolates carried papG allele III, papG allele I, Univcnf, iutA and hlyA. About 68.2% of the isolates carried two or more virulence genes and 41.8% carried three or more. Moreover, the isolates had 71 different profiles of virulence genes, where the most common profiles were fimH alone (86 isolate), fimH + iroN _{E. coli} (35 isolate), fimH + papC (20 isolate), and fimH + papC + iroN _{E. coli} (13 isolate). The adhesion, capsule synthesis and toxins secretion genes were significantly associated (p ˂ 0.01) with each other. These results call for awareness about the risk of food animals as reservoirs of ESBL uropathogenic E. coli that would threaten public health and limits the treatment options for urinary tract infections.

Epidemiology of Complicated Urinary Tract Infections due to Enterobacterales among Adult Patients Presenting in Emergency Departments Across the United States

In this multicenter study of adult patients who presented to the emergency department with an Enterobacterales complicated urinary tract infection (cUTI), high rates of resistance and co-resistance to commonly used oral antibiotics (fluoroquinolones, trimethoprim-sulfamethoxazole, nitrofurantoin, and third-generation cephalosporins) were observed.

Retrospective Cohort Study of the 12-Month Epidemiology, Treatment Patterns, Outcomes, and Healthcare Costs Among Adult Patients with Complicated Urinary Tract Infections

Background

Limited data are available in the United States on the 12-month epidemiology, outpatient (OP) antibiotic treatment patterns, outcomes, and costs associated with complicated urinary tract infections (cUTIs) in adult patients.

Methods

A retrospective observational cohort study of adult patients with incident cUTIs in IBM MarketScan Databases between 2017 and 2019 was performed. Patients were categorized as OP or inpatient (IP) based on initial setting of care for index cUTI and were stratified by age (<65 years vs ≥65 years). OP antibiotic treatment patterns, outcomes, and costs associated with cUTIs among adult patients over a 12-month follow-up period were examined.

Results

During the study period, 95 322 patients met inclusion criteria. Most patients were OPs (84%) and age <65 years (87%). Treatment failure (receipt of new unique OP antibiotic or cUTI-related ED visit/IP admission) occurred in 23% and 34% of OPs aged <65 years and ≥65 years, respectively. Treatment failure was observed in >38% of IPs, irrespective of age. Across both cohorts and age strata, >78% received ≥2 unique OP antibiotics, >34% received ≥4 unique OP antibiotics, >16% received repeat OP antibiotics, and >33% received ≥1 intravenous (IV) OP antibiotics. The mean 12-month cUTI-related total health care costs were $4697 for OPs age <65 years, $8924 for OPs age >65 years, $15 401 for IPs age <65 years, and $17 431 for IPs age ≥65 years.

Conclusions

These findings highlight the substantial 12-month health care burden associated with cUTIs and underscore the need for new outpatient treatment approaches that reduce the persistent or recurrent nature of many cUTIs.

Oral Tebipenem Pivoxil Hydrobromide in Complicated Urinary Tract Infection

BACKGROUND

There is a need for oral antibiotic agents that are effective against multidrug-resistant gram-negative uropathogens. Tebipenem pivoxil hydrobromide is an orally bioavailable carbapenem with activity against uropathogenic Enterobacterales, including extended-spectrum beta-lactamase-producing and fluoroquinolone-resistant strains.

METHODS

In this phase 3, international, double-blind, double-dummy trial, we evaluated the efficacy and safety of orally administered tebipenem pivoxil hydrobromide as compared with intravenous ertapenem in patients with complicated urinary tract infection or acute pyelonephritis. Patients were randomly assigned, in a 1:1 ratio, to receive oral tebipenem pivoxil hydrobromide (at a dose of 600 mg every 8 hours) or intravenous ertapenem (at a dose of 1 g every 24 hours) for 7 to 10 days (or up to 14 days in patients with bacteremia). The primary efficacy end point was overall response (a composite of clinical cure and favorable microbiologic response) at a test-of-cure visit (on day 19, within a ±2-day window) in the microbiologic intention-to-treat population. The noninferiority margin was 12.5%.

RESULTS

A total of 1372 hospitalized adult patients were enrolled; 868 patients (63.3%) were included in the microbiologic intention-to-treat population (50.8% of whom had complicated urinary tract infections and 49.2% of whom had pyelonephritis). An overall response was seen in 264 of 449 patients (58.8%) who received tebipenem pivoxil hydrobromide, as compared with 258 of 419 patients (61.6%) who received ertapenem (weighted difference, -3.3 percentage points; 95% confidence interval [CI], -9.7 to 3.2). Clinical cure at the test-of-cure visit was observed in 93.1% of the patients in the microbiologic intention-to-treat population who received tebipenem pivoxil hydrobromide and 93.6% of patients who received ertapenem (weighted difference, -0.6 percentage point; 95% CI, -4.0 to 2.8); the majority of patients with microbiologic response failures at the test-of-cure visit were asymptomatic patients with recurrent bacteriuria. Secondary and subgroup analyses were supportive of the primary analysis. Adverse events were observed in 25.7% of patients who received tebipenem pivoxil hydrobromide and in 25.6% of patients who received ertapenem; the most common adverse events were mild diarrhea and headache.

CONCLUSIONS

Oral tebipenem pivoxil hydrobromide was noninferior to intravenous ertapenem in the treatment of complicated urinary tract infection and acute pyelonephritis and had a similar safety profile. (Funded by Spero Therapeutics and the Department of Health and Human Services; ADAPT-PO ClinicalTrials.gov number, NCT03788967.).

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.

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

BACKGROUND

Urinary tract infections (UTIs), which are usually caused by bacteria in the Enterobacterales family, are a common reason for outpatient visits. Appropriate empiric therapy for UTIs requires an understanding of antibiotic resistance in the community. In this nationwide study, we examined trends in antibiotic resistance in urinary Enterobacterales isolates from ambulatory patients in the United States (US).

METHODS

We analyzed the antimicrobial susceptibility profiles (extended-spectrum beta-lactamase [ESBL]-producing phenotype and not susceptible [NS] to beta-lactams, trimethoprim/sulfamethoxazole [TMP/SMX], fluoroquinolones [FQ], or nitrofurantoin [NFT]) of 30-day non-duplicate Enterobacterales isolates from urine cultures tested at ambulatory centers in the BD Insights Research Database (2011-2020). The outcome of interest was the percentage of resistant isolates by pathogen and year. Multi-variable generalized estimating equation models were used to assess trends in resistance over time and by additional covariates.

RESULTS

A total of 338 US facilities provided data for > 2.2 million urinary Enterobacterales isolates during the 10-year study. Almost three-quarters (72.8%) of Enterobacterales isolates were Escherichia coli. Overall unadjusted resistance rates in Enterobacterales isolates were 57.5%, 23.1%, 20.6%, and 20.2% for beta-lactams, TMP/SMX, FQ, and NFT, respectively, and 6.9% had an ESBL-producing phenotype. Resistance to two or more antibiotic classes occurred in 16.4% of isolates and 5.5% were resistant to three or more classes. Among isolates with an ESBL-producing phenotype, 70.1%, 59.9%, and 33.5% were NS to FQ, TMP/SMX, and NFT, respectively. In multivariable models, ESBL-producing and NFT NS Enterobacterales isolates increased significantly (both P < 0.001), while other categories of resistance decreased. High rates (≥ 50%) of beta-lactam and NFT resistance were observed in Klebsiella isolates and in non-E. coli, non-Klebsiella Enterobacterales isolates.

CONCLUSIONS

Antimicrobial resistance was common in urinary Enterobacterales isolates. Isolates with an ESBL-producing phenotype increased by about 30% between 2011 and 2020, and significant increases were also observed in NFT NS Enterobacterales isolates. Resistance rates for all four antibiotic classes were higher than thresholds recommended for use as empiric therapy. Non-E. coli Enterobacterales isolates showed high levels of resistance to commonly used empiric antibiotics, including NFT. These data may help inform empiric therapy choices for outpatients with UTIs.

OUP accepted manuscript

Objectives

STM-001, a retargeted glycopeptide, is active against MDR E. coli expressing ESBLs including carbapenemases. Herein, we assessed its capability to combat E. coli complicated urinary tract infections (cUTI) in mice driven by clinically important serine (CTX-M-15) and metallo-β-lactamases (NDM-1).

Methods

Plasma and urine pharmacokinetics following IV administration of STM-001 (1–50 mg/kg) were determined in mice via LC-MS/MS. The effects on bacterial burden (kidney, bladder and urine) were determined in a 7 day mouse cUTI model whereby STM-001 was administered q12h or q24h at 2–100 mg/kg/day from Day 4. Efficacy was assessed by the change in log₁₀ cfu/g or log₁₀ cfu/mL from vehicle-treated infected mice.

Results

MICs of STM-001 for CTX-M-15 and NDM-1 E. coli were 8 and 16 mg/L, respectively. Blood pharmacokinetic profile was linear and dose-dependent with low clearance of 9.49 ± 0.31 mL/min/kg, V = 0.63 ± 0.02 L/kg and t_½ = 1.16 ± 0.03 h. High STM-001 concentrations were recovered in urine 0–8 h post-administration, reaching up to 120-fold above its MIC. In cUTI efficacy studies, STM-001 (1–50 mg/kg, q12h) reduced CTX-M-15 burden by log₁₀ 4.31 (kidney), 3.95 (bladder) and 4.82 (urine) compared with vehicle-treated animals (P < 0.0001). STM-001 also reduced NDM-1 burden by log₁₀ 3.89 (kidney), 3.76 (bladder) and 3.08 (urine) (P < 0.0001), with similar inhibitory effects following q24h dosing.

Conclusions

STM-001 was highly effective in reducing E. coli burden in kidney, bladder and urine in mouse cUTI models. The observed efficacy with either dosing regimen indicates potential low humanized doses of 1–5 mg/kg. These data support further development of STM-001 as an innovative, carbapenem-sparing antibiotic to combat human cUTIs.

Clinical impact of multidrug-resistant bacteria in older hospitalized patients with community-acquired urinary tract infection

Introduction

Previous studies have described some risk factors for multidrug-resistant (MDR) bacteria in urinary tract infection (UTI). However, the clinical impact of MDR bacteria on older hospitalized patients with community-acquired UTI has not been broadly analyzed. We conducted a study in older adults with community-acquired UTI in order to identify risk factors for MDR bacteria and to know their clinical impact.

Methods

Cohort prospective observational study of patients of 65 years or older, consecutively admitted to a university hospital, diagnosed with community-acquired UTI. We compared epidemiological and clinical variables and outcomes, from UTI due to MDR and non-MDR bacteria. Independent risk factors for MDR bacteria were analyzed using logistic regression.

Results

348 patients were included, 41.4% of them with UTI due to MDR bacteria. Median age was 81 years. Hospital mortality was 8.6%, with no difference between the MDR and non-MDR bacteria groups. Median length of stay was 5 [4–8] days, with a longer stay in the MDR group (6 [4–8] vs. 5 [4–7] days, p = 0.029). Inadequate empirical antimicrobial therapy (IEAT) was 23.3%, with statistically significant differences between groups (33.3% vs. 16.2%, p < 0.001). Healthcare-associated UTI variables, in particular previous antimicrobial therapy and residence in a nursing home, were found to be independent risk factors for MDR bacteria.

Conclusions

The clinical impact of MDR bacteria was moderate. MDR bacteria cases had higher IEAT and longer hospital stay, although mortality was not higher. Previous antimicrobial therapy and residence in a nursing home were independent risk factors for MDR bacteria.

Challenges to Early Discharge of Patients with Upper Urinary Tract Infections by ESBL Producers: TMP/SMX as a Step-Down Therapy for Shorter Hospitalization and Lower Costs

Background

Urinary tract infections (UTIs) caused by extended spectrum beta-lactamase (ESBL) producing pathogens have increased and are treated with carbapenem in general. Carbapenem use is associated with prolonged hospitalization or daily outpatient visit. The aim of this study was to investigate patients with UTIs by ESBL-producing pathogens for early discharge using an old oral antibiotic, trimethoprim-sulfamethoxazole (TMP-SMX), which is susceptible to ESBL-producing pathogens.

Methods

Data on UTIs caused by ESBL-producing pathogens from a single tertiary hospital were collected retrospectively. Patients who had been treated with intravenous carbapenems or oral TMP/SMX were included. Patients’ clinical and microbiological outcomes were compared between oral TMP/SMX and ertapenem treatment groups.

Results

A total of 103 patients were included, 21 of whom had been treated with TMP/SMX, whereas 82 with ertapenem. Clinical outcomes between the two groups were not significantly different (TMP/SMX: 90.5%; ertapenem: 84.1%, p = 0.73). The microbiological cure rate was higher in the TMP/SMX group than in the ertapenem group (90.5% vs 58.5%, respectively, p = 0.01). The mean duration of hospitalization was significantly shorter in the TMP/SMX group than in the ertapenem group (8.00 ± 10.50 days vs 14.00 ± 37.00 days, p = 0.07). The mean duration of antibiotic treatment was longer in the ertapenem group than in the TMP/SMX group (16.45 ± 4.77 vs 12.76 ± 5.37 days, p = 0.006).

Conclusion

For susceptible pathogens, TMP/SMX may enable early discharge as an effective oral antibiotic treatment option for UTIs caused by ESBL-positive pathogens. Additionally, use of oral antibiotics can shorten hospital stays and reduce medical costs.

Trends in prevalence of extended-spectrum beta-lactamase-producing Escherichia coli isolated from patients with community- and healthcare-associated bacteriuria: results from 2014 to 2020 in an urban safety-net healthcare system

BACKGROUND

The prevalence of infections caused by extended-spectrum beta-lactamase producing Escherichia coli (ESBL-E. coli) is increasing worldwide, but the setting in which this increase is occurring is not well defined. We compared trends and risk factors for ESBL-E. coli bacteriuria in community vs healthcare settings.

METHODS

We collected electronic health record data on all patients with E. coli isolated from urine cultures in a safety-net public healthcare system from January 2014 to March 2020. All analyses were stratified by healthcare-onset/associated (bacteriuria diagnosed > 48 h after hospital admission or in an individual hospitalized in the past 90 days or in a skilled nursing facility resident, N = 1277) or community-onset bacteriuria (bacteriuria diagnosed < 48 h after hospital admission or in an individual seen in outpatient clinical settings without a hospitalization in the past 90 days, N = 7751). We estimated marginal trends from logistic regressions to evaluate annual change in prevalence of ESBL-E. coli bacteriuria among all bacteriuria. We evaluated risk factors using logistic regression models.

RESULTS

ESBL-E. coli prevalence increased in both community-onset (0.91% per year, 95% CI 0.56%, 1.26%) and healthcare-onset/associated (2.31% per year, CI 1.01%, 3.62%) bacteriuria. In multivariate analyses, age > 65 (RR 1.88, CI 1.17, 3.05), male gender (RR 2.12, CI 1.65, 2.73), and Latinx race/ethnicity (RR 1.52, CI 0.99, 2.33) were associated with community-onset ESBL-E. coli. Only male gender (RR 1.53, CI 1.03, 2.26) was associated with healthcare-onset/associated ESBL-E. coli.

CONCLUSIONS

ESBL-E. coli bacteriuria frequency increased at a faster rate in healthcare-associated settings than in the community between 2014 and 2020. Male gender was associated with ESBL-E. coli bacteriuria in both settings, but additional risks-age > 65 and Latinx race/ethnicity-were observed only in the community.

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.

Antimicrobial Resistance Trends in Urine Escherichia coli Isolates From Adult and Adolescent Females in the United States From 2011-2019: Rising ESBL Strains and Impact on Patient Management

Background

Uncomplicated urinary tract infection (uUTI) is predominantly caused by Escherichia coli, which has increasing antimicrobial resistance (AMR) at the United States (US)-community level. As uUTI is often treated empirically, assessing AMR is challenging, and there are limited contemporary data characterizing period prevalence in the US.

Methods

This was a retrospective study of AMR using Becton, Dickinson and Company Insights Research Database (Franklin Lakes, New Jersey, US) data collected 2011–2019. Thirty-day, nonduplicate Escherichia coli urine isolates from US female outpatients (aged ≥12 years) were included. Isolates were evaluated for nonsusceptibility (intermediate/resistant) to trimethoprim-sulfamethoxazole, fluoroquinolones, or nitrofurantoin, and assessed for extended-spectrum β-lactamase production (ESBL+) and for ≥2 or ≥3 drug-resistance phenotypes. Generalized estimating equations were used to model AMR trends over time and by US census region.

Results

Among 1 513 882 E. coli isolates, the overall prevalence of isolates nonsusceptible to trimethoprim-sulfamethoxazole, fluoroquinolones, and nitrofurantoin was 25.4%, 21.1%, and 3.8%, respectively. Among the isolates, 6.4% were ESBL+, 14.4% had ≥2 drug-resistance phenotypes, and 3.8% had ≥3. Modeling demonstrated a relative average yearly increase of 7.7% (95% confidence interval [CI], 7.2–8.2%) for ESBL+ isolates and 2.7% (95% CI, 2.2–3.2%) for ≥3 drug-phenotypes (both P < .0001). Modeling also demonstrated significant variation in AMR prevalence between US census regions (P < .001).

Conclusions

Period prevalence of AMR among US outpatient urine-isolated E. coli was high, and for multidrug-resistance phenotypes increased during the study period with significant variation between census regions. Knowledge of regional AMR rates helps inform empiric treatment of community-onset uUTI and highlights the AMR burden to physicians.

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.