Association between ESBLs Genes and Quinolone Resistance in Uropathogenic Escherichia coli Isolated from Patients with Urinary Tract Infection

 Urinary tract infection (UTI) is one of the most common infections worldwide. The aim of this study was to investigate the association between ESBLs genes and quinolone resistance in Uropathogenic Escherichia coli isolated from patients with urinary tract infection . A total of 150 E. coli isolates were collected from patients with urinary tract infection referring to Firouzgar Hospital in Tehran, Iran. Antimicrobial susceptibility of isolates were determined by disk diffusion method. Double-disk diffusion test was performed for phenotypic identification of extended-spectrum β-lactamase- (ESBL) producing isolates. PCR was used for the detection of ESBL-encoding genes in addition to quinolone (qnr) resistance genes.

There was a high resistance rate to most of the studied antimicrobial agents. Phenotypically, 75% of the isolates produced an ESBL enzyme and were resistant to different antimicrobial classes. In overall, 83% of the isolates carried ESBL genes, especially blaTEM and blaCTX-M  . 75% were positive for the quinolone resistance genes including qnrA , qnrB ,qnrS and qepA. These results indicate the association between the presence of various ESBLs genes and quinolone resistance in uropathogenic E. coli.


Resistance patterns show the increased incidence of antibacterial resistance in E. coli. Results of the current study indicate the high prevalence of ESBL-producing isolates and quinolone resistance genes. Simultaneous presence of genes responsible for antibacterial resistance has made the treatment of UTI more challenging than ever before.