HIGH BURDEN OF MULTIDRUG-RESISTANT UROPATHOGENIC ESCHERICHIA COLI AND PRESERVED SUSCEPTIBILITY TO NITROFURANTOIN AND FOSFOMYCIN: A CROSS-SECTIONAL STUDY FROM PESHAWAR, PAKISTAN

Abstract

Background: Urinary tract infections (UTIs) are among the most prevalent bacterial infections globally and are increasingly complicated by antimicrobial resistance (AMR). Uropathogenic Escherichia coli (UPEC) remain the principal causative agent, with rising multidrug resistance (MDR) compromising empirical treatment strategies. This study investigated the prevalence, antimicrobial susceptibility patterns, of UPEC isolates from UTI patients in Peshawar, Pakistan, with supplementary in silico analysis of β-lactamase enzymes.

Methods: A laboratory-based cross-sectional study was conducted between October and December 2025. Midstream urine samples (n = 70) from clinically suspected UTI patients were processed using standard microbiological methods. Identification of E. coli was confirmed via colony morphology, Gram staining, and biochemical assays. Antimicrobial susceptibility testing (AST) was performed using the Kirby–Bauer disk diffusion method following Clinical and Laboratory Standards Institute (CLSI 2024) guidelines. MDR was defined as resistance to at least one agent in three or more antimicrobial classes.

Results: E. coli was the predominant uropathogen, accounting for 35.7% of isolates. Antimicrobial susceptibility testing demonstrated markedly high resistance to commonly used antibiotics, including ampicillin (96%), cefotaxime (80%), azithromycin (80%), and amoxicillin–clavulanate and ceftriaxone (64% each). In contrast, nitrofurantoin, fosfomycin, and meropenem exhibited high efficacy, with 96% susceptibility rates. MDR was observed in 84% of isolates, with a small proportion (4%) classified as extensively drug-resistant (XDR).

Conclusion: The high prevalence of MDR E. coli limits the utility of commonly prescribed β-lactams for empirical therapy in this setting. Nitrofurantoin and fosfomycin remain effective first-line options. These findings underscore the necessity for routine AST-guided treatment and strengthened antimicrobial stewardship to mitigate the escalating AMR burden