Antimicrobial Resistance and ESBL-Associated Predictors Among Uropathogens: A 2019-2024 Isolate-Level Study

Area of Science:

• Clinical Microbiology
• Infectious Diseases
• Antimicrobial Resistance

Background:

• Urinary tract infections (UTIs) are common bacterial infections and a major driver of antimicrobial use.
• Increasing antimicrobial resistance, especially from extended-spectrum beta-lactamase (ESBL)-producing organisms, complicates UTI treatment.
• ESBL-producing organisms are linked to multidrug resistance, limiting empiric therapy options for UTIs.

Purpose of the Study:

• To characterize antimicrobial resistance patterns in uropathogens causing lower UTIs.
• To identify independent predictors of antimicrobial resistance in UTIs.
• To inform empiric treatment strategies and antimicrobial stewardship for UTIs.

Main Methods:

• Retrospective observational study of 1470 patients with suspected lower UTIs (2019-2024).
• Urine culture and antimicrobial susceptibility testing (AST) performed; interpreted using European Committee on Antimicrobial Susceptibility Testing (EUCAST) criteria.
• Multivariable generalized estimating equation (GEE) logistic regression used to identify resistance predictors, including ESBL production assessment.

Main Results:

• *Escherichia coli* was the most common uropathogen (66.0%).
• 17.3% of Gram-negative isolates were ESBL-positive.
• Resistance was high for ciprofloxacin (35.4%) and trimethoprim/sulfamethoxazole (31.7%); fosfomycin and nitrofurantoin remained active against *E. coli*.
• ESBL production was a strong predictor of resistance to multiple antibiotics (e.g., ciprofloxacin aOR 9.83, cefotaxime aOR 1337).

Conclusions:

• Antimicrobial resistance in uropathogens is heterogeneous, influenced by pathogen identity and ESBL production.
• ESBL status is a critical predictor of resistance, guiding empiric treatment decisions for UTIs.
• Findings underscore the importance of ESBL testing for effective antimicrobial stewardship in managing UTIs.