Development of Predictive Models to Inform a Novel Risk Categorization Framework for Antibiotic Resistance in E. coli-Causing Uncomplicated Urinary Tract Infection.

BACKGROUND: In clinical practice, challenges in identifying patients with uncomplicated urinary tract infections (uUTIs) at risk of antibiotic non-susceptibility may lead to inappropriate prescribing and contribute to antibiotic resistance. We developed predictive models to quantify risk of non-susceptibility to four commonly prescribed antibiotic classes for uUTI, identify predictors of non-susceptibility to each class, and construct a corresponding risk categorization framework for non-susceptibility. METHODS: Eligible females aged ≥12 years with E. coli-caused uUTI were identified from Optum's de-identified Electronic Health Record dataset (10/1/2015‒2/29/2020). Four predictive models were developed to predict non-susceptibility to each antibiotic class and a risk categorization framework was developed to classify patients' isolates as low, moderate, and high risk of non-susceptibility to each antibiotic class. RESULTS: Predictive models were developed among 87487 patients. Key predictors of having a non-susceptible isolate to ≥3 antibiotic classes included number of previous UTI episodes, prior ß-lactam non-susceptibility, prior fluoroquinolone treatment, census bureau region, and race. The risk categorization framework classified 8.1%, 14.4%, 17.4%, and 6.3% of patients as having isolates at high risk of non-susceptibility to nitrofurantoin, trimethoprim-sulfamethoxazole, ß-lactams, and fluoroquinolones, respectively. Across classes, the proportion of patients categorized as having high-risk isolates was 3-12 folds higher among patients with non-susceptible isolates versus susceptible isolates. CONCLUSIONS: Our predictive models highlight factors that increase risk of non-susceptibility to antibiotics for uUTIs, while the risk categorization framework contextualizes risk of non-susceptibility to these treatments. Our findings provide valuable insight to clinicians treating uUTIs and may help inform empiric prescribing in this population.

Impact of the 2019 Food and Drug Administration Guidance for Uncomplicated Urinary Tract Infection on Treatment Response Rates: A Reanalysis of a Clinical Trial of Nitrofurantoin vs Fosfomycin.

Background: Current US Food and Administration (FDA) guidance recommends that the primary efficacy endpoint for uncomplicated urinary tract infection (uUTI) clinical trials be a composite of clinical and microbiological responses. We applied these criteria to a previous clinical trial to determine the impact on treatment outcomes. Methods: We conducted a patient-level reanalysis of a randomized clinical trial of nitrofurantoin versus fosfomycin for treatment of uUTI in nonpregnant adult women. Women were included in the reanalysis if they had 2 or more signs/symptoms of uUTI and a single bacterial species isolated from baseline urine culture at ≥105 colony-forming units (CFU)/mL. The applied primary efficacy endpoint-therapeutic response-required both clinical resolution of signs/symptoms and reduction of the infecting bacterial pathogen to <103 CFU/mL at day 14 post-treatment completion. Results: Two hundred eleven of 513 (41%) patients were eligible for inclusion in the reanalysis. Among these patients, 74% (76/103) and 69% (75/108) in the nitrofurantoin and fosfomycin groups, respectively, achieved clinical resolution by day 14. Similarly, 70% (72/103) and 67% (72/108) in each group achieved microbiological success at day 14. As such, 59% (61/103) and 57% (62/108) of women in each group met the primary efficacy endpoint-therapeutic success-at day 14. In comparison, 75% and 66% of patients in each group achieved clinical resolution at day 14 in the initial clinical trial. Conclusions: Applying current FDA guidance resulted in lower composite efficacy rates than clinical resolution alone as observed in the initial clinical trial. This may limit the ability to compare antibiotic treatment effects between historical and future clinical trials.

A systematic scoping review of faropenem and other oral penems: treatment of Enterobacterales infections, development of resistance and cross-resistance to carbapenems.

Background: Antimicrobial resistance is an urgent global healthcare concern. Beyond carbapenems as broad-spectrum, often 'last resort' antibiotics, oral penem antibiotics currently are approved only in Japan and India, used for the treatment of indications including urinary tract infections (UTIs). Exploring oral penem use to better understand the impact of antibiotic resistance on public health would help inform the management of infectious diseases, including UTIs. Scoping Review Methodology: This scoping review investigated the impact of faropenem and other oral penems on Enterobacterales infection treatment and evaluated evidence for faropenem resistance and cross-resistance to carbapenems. PubMed, Embase, J-STAGE and CiNii were searched for relevant English- or Japanese-language articles published between 1 January 1996 and 6 August 2021. Key Findings: From 705 unique publications, 29 eligible articles were included (16 in vitro studies; 10 clinical trials; 2 in vitro and in vivo studies; and 1 retrospective medical chart review). Limited evidence described faropenem to treat infectious disease; only four randomized clinical trials were identified. Faropenem dosing regimens varied broadly within and between indications. One study indicated potential dependence of penem efficacy on underlying antibiotic resistance mechanisms, while several studies reported UTI persistence or recurrence after faropenem treatment. In vitro MIC data suggested some potential bacterial resistance to faropenem, while limited clinical data showed resistance emergence after faropenem treatment. Preliminary in vitro evidence suggested faropenem resistance might foster cross-resistance to carbapenems. Overall, very limited clinical evidence describes faropenem for treating infectious diseases. Preclinical and clinical research investment and dedicated community surveillance monitoring is crucial for understanding faropenem treatment patterns, resistance and potential cross-resistance to carbapenems.