The current study was aimed to detect qnrA, qnrB, qnrC, qnrD and qnrS genes in quinolone-resistance extended-spectrum beta-lactamases (ESBL)-producing Escherichia coli isolates that recovered from patients with urinary tract infection in Babylon Province, Iraq. Uropathogenic E. coli (UPEC) was regarded as the most important causative agent of urinary tract infections. Fluoroquinolones are regularly used in the management of these infections; on the other hand, in recent years, an increasing rate of quinolone resistance has been stated globally. Clinical isolates of UPEC were collected from patients with infection of urinary tract and identified by standard laboratory protocols. PCR was used for detection of quinolone resistance genes (qnrA, qnrB, qnrC, qnrD and qnrS) in ESBL-producing isolates, and sequencing of some qnr genes confirmed the results. Out of 208 urine specimens, 42 UPEC isolates of ESBL producing were detected; of them, 27 (64.28%) isolates were found to be resistant to quinolones. PCR results revealed that out of 27 UPEC, five (18.51%) isolates were found to carry both genes qnrS and qnrB, whereas four (14.81%) isolates were harbored qnrD and qnrA, and no isolate was found to have qnrC. Sequencing of qnrB and qnrS genes revealed that mutational changes were observed in qnrB gene; however, no mutational variation was observed in qnrS gene.
The results of the current study revealed the dissemination of ESBL genes in all UPEC isolates that carry the plasmid-mediated qnr genes with low frequency among the clinical isolates and UPEC isolates; these results confirmed that the quinolone resistance in Babylon Province, Iraq might be because of chromosomal genes for this resistance.