The prevalence of plasmid-mediated quinolone resistance genesamong Escherichia coli strains isolated from urinary tract infections insouthwest Iran

Background and Aim : Background: The extensive and inappropriate use of quinolones,frequently used as an effective treatment for urinary tract infection (UTI) patients, has led toresistance to these antibiotics. This study was designed to determine the prevalence of quinoloneresistance and plasmid-mediated quinolone resistance (PMQR) genes among extended-spectrumbeta-lactamase (ESBL)-producing Escherichia coli isolates.Methods : Methods: One hundred and fourteen E. coli isolates were collected from patients’ urinesamples. The susceptibility of iso lates to selected antibiotics was tested by the Kirby-Bauer diskdiffusion method. ESBL-producing isolates were identified phenotypically using a combinationdisk test. Using specific primers, the frequency of aac (۶’)-Ib, qnrA, qnrB, qnrC, qnrD, qnrS, andqepA genes was investigated by polymerase chain reaction (PCR).Results : Results: Among ۲۶ ESBL-producing isolates, the highest resistance rate was observedtoward nalidixic acid (۸۰.۸%) and ciprofloxacin (۶۱.۵%), respectively. Ninety-seven (۸۵%) of allisolates harbored at least one PMQR gene, the most frequent one being the aac (۶’)-Ib-cr variant(۴۷.۴%). The coexistence of aac (۶’)-Ib-cr variant and qnrB were the most broadly distributedgenotype among quinolone resistance isolates. Notably, none of the isolates contained the qnrC,qnrD, and qepA genes.Conclusion : Conclusions: Our results highlight the significant prevalence of PMQR genes inESBL-producing E. coli isolates in this region. Also, the aac (۶’)-Ib-cr variant was the mostfrequent gene, particularly in ESBL-positive isolates. A regular periodic monitoring program isneeded to control and hinder the spread of antibiotic resistance and contributed genes among UTIcausingE. coli isolates.

کلیدواژه ها:

Escherichia coli ، Urinary tract infection ، Quinolone ، ESBL ، qnr