Phenotypic and Molecular Characterization of ESBL-Producing Escherichia Coli in Urinary Tract Infections at a Tertiary Care Centre In India

Background: Extended-spectrum beta-lactamase (ESBL)-producing Escherichia coli has emerged as a major uropathogen with significant therapeutic challenges. This study aimed to investigate the prevalence, antimicrobial resistance pattern, and molecular characteristics of ESBL-producing E. coli isolated from urine samples in a tertiary care hospital. Aim and Objective: To study the phenotypic and molecular characterization of ESBL-producing Escherichia coli in urinary tract infections at a tertiary care centre. Material and Methods: A total of 836 urine samples were processed; 366 (49%) yielded E. coli isolates. Phenotypic screening for ESBL was done using ceftazidime-clavulanic acid disk synergy test. PCR was performed for detection of blaTEM, blaCTX-M, and blaSHV genes in ESBL-positive isolates. Results: Out of 366 E. coli isolates, 82 (22.5%) were ESBL producers. Among them, 53.7% carried blaTEM, 35.4% blaCTX-M, and 10.9% blaSHV. Female predominance was seen (70.5%). Most isolates showed 100% susceptibility to meropenem, nitrofurantoin, fosfomycin, and ceftazidime-clavulanate, while high resistance was noted against ceftriaxone and ceftazidime. Conclusion: The high frequency of ESBL-producing E. coli among urinary isolates emphasizes the need for routine molecular detection and prudent antibiotic use in clinical settings.