Distribution of fosfomycin and AmpC β-lactamase resistance genes in urinary Escherichia coli isolates obtained from patients admitted to an educational hospital in Ahvaz, southwest Iran

Abstract

BackgroundEscherichia coli is the most important etiologic agent of urinary tract infections (UTIs). Today, the emergence of antibiotic resistance in UTI-causing E. coli isolates is increasing. This study aimed to investigate the extended-spectrum β-lactamases (ESBLs) production, AmpC enzymes, and fosfomycin resistance genes in E. coli clinical isolates obtained from patients with UTIs. MethodsFrom December 2018 to June 2019, the E. coli isolates were collected from patients with UTI who were referred to Golestan teaching hospital in Ahvaz, Iran. Then, the antimicrobial susceptibility testing, ESBL and AmpC β-lactamase production were performed by disk diffusion method. Finally, the polymerase chain reaction was done to investigate the presence of fosfomycin resistance (fosC2, fosA3) and AmpC (blaCMY-2, blaACC) genes. ResultsIn total, 90 E. coli isolates were collected. The most effective antibiotics were fosfomycin, nitrofurantoin and imipenem with 86 (95.5%), 82 (91.1%), and 78 (86.7%) susceptibility, respectively. AmpC beta-lactamase was confirmed in 18 (20%) isolates. Moreover, 63 (90%) isolates were found as ESBL producers and 6 (6.6%) had both AmpC and ESBL β-lactamases. The frequency rates of blaCMY-2 and blaACC resistance genes in AmpC-producing isolates was 12 (13.3%) and 15 (83.3%), respectively. The fosC2 and fosA3 genes were not detected in E. coli isolates. ConclusionCurrent study revealed the emergence of E. coli isolates harboring ESBL and AmpC enzymes in southwest region of Iran. This study highlighted the need of our laboratories to adopt an appropriate method for continuous screening of ESBL and AmpC in clinical isolates on a daily basis.