Publication:

Detection of ESBL and MBL among uropathogenic Escherichia coli in a tertiary care hospital in Maharashtra

Background Urinary tract infection (UTI) is one of the most common infections worldwide. Although the spectrum of etiological agents causing UTI has remained relatively constant, their antimicrobial susceptibility patterns have changed over time due to the emergence of resistant strains. Escherichia coli, a gram-negative bacillus, is the most common uropathogen. Antimicrobial resistance mediated by extended-spectrum β-lactamases (ESBL) and metallo-β-lactamases (MBL) in E. coli contributes significantly to prolonged hospital stay and increased treatment costs in patients with UTI.

Methods All urine samples received from inpatients and outpatients in the microbiology laboratory were processed for microscopy and cultured on Blood agar and MacConkey agar. Isolates were identified based on colony morphology and standard biochemical tests. Antimicrobial susceptibility testing was performed by the Kirby–Bauer disk diffusion method according to CLSI guidelines. ESBL production in E. coli was detected by the cephalosporin/clavulanate disk test and MBL production by the imipenem/EDTA disk test.

Results Of the 2234 urine samples processed, 845 yielded significant growth. E. coli was the most common isolate (41.89%). The uropathogenic E. coli (UPEC) strains showed more resistance to ampicillin (96.78%) and cephalosporins (93.55%) and comparatively less resistance to imipenem (11.93%) and nitrofurantoin (13.55%). ESBL and MBL production were observed in 55.81% and 10.65% of E. coli isolates, respectively.

Conclusions The increasing prevalence of ESBL- and MBL-producing E. coli among uropathogens is a major concern. Judicious and rational use of antimicrobial agents, guided by local susceptibility patterns, is essential to reduce treatment costs, limit morbidity and curb the further spread of resistance in UTI cases.