Emergence of Fosfomycin Resistance Among ESBL-Producing Escherichia coli in Abadan, Southwestern Iran

Escherichia coli is a key pathogen responsible for various infections, such as urinary tract infections, gastroenteritis, and wound infections. The increasing occurrence of antimicrobial resistance, particularly in extended-spectrum β-lactamase (ESBL)-producing strains, poses a significant global health threat. This study aimed to assess the prevalence of fosfomycin resistance genes in ESBL-producing E. coli isolates from Abadan, southwest Iran.

From December 2020 to June 2021, 90 E. coli isolates were obtained from clinical labs and healthcare centers affiliated with Abadan University of Medical Sciences. Antimicrobial susceptibility and ESBL production were determined using the disk diffusion method, while polymerase chain reaction was employed to detect relevant resistance genes.

Fosfomycin resistance was observed in 5.6% of E. coli isolates. ESBL production occurred in 31.1% of isolates, with over half (53.6%) carrying the bla _CTX-M gene. Among ESBL producers, the glpT gene was the most prevalent (50%), followed by fosA3 (10.7%) and fosC2 (3.6%). Notably, the fosA gene was absent in all examined isolates.

This study reveals a rising prevalence of fosfomycin resistance among ESBL-producing E. coli isolates in Abadan, Iran. Ongoing surveillance of fosfomycin resistance is crucial for informing effective antimicrobial stewardship and treatment strategies.