Frequency of qnr genes in Escherichia coli strains resistant to quinolones isolated from Ilam Imam khomani hospital and Tehran Milad hospital

Extensive use of quinolones has been associated with raising level of resistance. In the current study, we focused on assessing the prevalence of Escherichia coli resistance to quinolones and frequency of qnr genes. One hundred and fifty Escherichia coli isolates were identified. PCR was performed for detection of qnrA، qnrB و qnrS genes. Of 150 isolates, sixty nine isolates (46%) were resistance to ciprofloxacin. Frequency of qnrA، qnrB و qnrS were 28. 9% (20 isolates), 56. 5% (39 isolates), 31. 8% (22 isolates) and 95. 65% (66 isolates) respectively. Among qnr genes resistance to ciprofloxacin qnrB had high freqency (56. 5%). One hundred six isolates (70. 6%) had one gene only. Seven isolates (10. 1%) had three genes. Twenty (28. 9%) isolates had two genes qnrA and qnrB, eleven (15. 9%) isolate had two genes qnrB and qnrS, and eight (11. 5%) isolates had two genes qnrA and qnrS. Our study showed high frequency of qnr quinolone resistance gense in Ilam and Tehran (Milad) hospitals. Keywords: Ciprofloxacin, quinolone, Ilam, Tehran