Evaluation of the frequency of plasmid-mediated quinolone resistance genes in clinical isolates of Escherichia coli and Klebsiella spp. in Tehran

The qnr gene is a plasmid carrying resistant genes involved in bacterial resistance to quinolone resistance plasmid factors. The aim of this study was to evaluate the presence of either gene qnr, a plasmid resistant gene, and aac (6) -Ib-cr, from Escherichia coli and Klebsiella spp isolated from clinical samples.
In this sectional study, 132 E. coli and 98 Klebsiella isolates were collected from patients with the UTI referred to the ayatollah Taleghani Hospital in Tehran. Antibiotic resistance was evaluated using Kirby-Bauer and CLSI criteria. After DNA extraction, qnr and aac(6)-Ib-cr genes were amplified using PCR method.
In this study, E. coli strains were resistant to ciprofloxacin and nalidixic acid in a ratio of 47.72 % and 62.12 %, respectively. Also, Klebsiella isolates were resistant to ciprofloxacin and nalidixic acid in a ratio of 38.77 % and 51.02 %, respectively. In the present study, the frequency of aac(6)-lb-cr, qnrA , qnrB, qnrS genes in E. coli were 30.18, 37.73, 67.92, 33.96 %. Also these frequency were 31.42, 22.58, 68.57, 31.42 % in Klebsiella.
This study showed high frequency of the ciprofloxacin resistant qnr gense in E. coli and Klebsiella isolates from Tehran.