Comparison of quinolone and beta-lactam resistance among Escherichia coli strains isolated from urinary tract infections.

Tayebi, Zahra; Heidari, Hamid; Kazemian, Hossein; Ghafoori, Seyed Mohammad; Boroumandi, Shahram; Houri, Hamidreza

The growing frequency of antibiotic resistances is now a universal problem. Increasing resistance to new generations of β-lactam and quinolone antibiotics in multidrug-resistant Enterobacteriaceae isolates is considered an emergency health issue worldwide. The aim of this study was to evaluate plasmid-mediated quinolone resistance genes in ESBL-producing Escherichia coli isolated from urinary tract infections (UTIs). In our study ESBL-producing isolates were assessed by screening methods. After determination of antimicrobial susceptibility testing, detection of ESBLs and quinolone resistance genes was performed. A total of 97 ESBL-producing E. coli were determined. The bla-TEM, bla-SHV and bla-CTX-M genes were detected in 90 isolates. The bla-TEM was the most frequently detected gene (46.4%), followed by bla-SHV (31.9%) and bla-CTX-M (14.4%). The most prevalent quinolone resistance gene among ESBL-producing isolates was oqxAB which was found in 67 isolates (69.1%). The frequencies of the aac(6')-Ib-cr, qnr and qepA were 65 (67%), 8 (8.2%) and 6 (6.2%), respectively. Our data indicate that the prevalence of plasmid-mediated quinolone resistance genes in ESBL-positive isolates is increasing. The co-dissemination of PMQR and ESBL genes among E. coli isolates can be considered a threat to public health. Therefore, prescription of antibiotics against infectious disease should be managed carefully.