Evaluation of resistance to fluoroquinolones and molecular analysis of resistance genes among Enterobacteriaceae isolated from clinical samples in Iran

Background and Aim : Fluoroquinolones (FQs) resistance due to their extensive clinical use has been a major problem in clinical settings that lead to limitation of treatment. This study aimed to investigate the resistance genes to FQs in Enterobacteriaceae isolates in Azerbaijan, Iran. Methods : In this descriptive-analytical study, eighty-eight Enterobacteriaceae isolated from clinical samples were collected. The biochemical and molecular diagnosis were evaluated for resistance to different antibiotics by disk diffusion agar according to CLSI recommendations and screening for ciprofloxacin-resistant isolates. The presence of mutations in quinolone resistance genes were detected by the PCR and direct sequencing.Results : Overall, ۶۳ isolates (۷۱.۶%) were resistant to at least one of the FQ antibiotics. The highest resistance rate was against ampicillin (۸۸.۶%) followed by trimethoprim-sulfamethoxazole (۷۰.۵%), ciprofloxacin (۵۴.۵%), and moxifloxacin (۵۳.۴%). All FQ-resistant Enterobacteriaceae had a mutation in gyrA. We found ۱۰۰% and ۷۶% mutation at Ser۸۳Leu and Asp۸۷Asn of gyrA, respectively. Mutations of gyrB were including Ser۳۵۹Ala+ Ser۳۶۷Thr (۱.۵%) and Ser۳۶۶Pro+ Arg۴۷۸Trp (۱.۵%). Forty-eight (۹۲%) of FQ-resistant Enterobacteriaceae were positive for plasmid-mediated quinolone resistance (PMQR) genes. A total of ۶۴.۲% (۲۷/۴۲) FQ-resistance Enterobacteriaceae that containing ۶۸.۵% (۲۴/۳۵) E. coli and ۵۷% (۴/۷) E. cloacae isolates presented a reduction in ompF expression level.Conclusion : The rate of resistance to FQ and multidrug resistance is high in Enterobacteriaceae clinical isolates in the northwest of Iran and the double mutations in gyrA and parC result in high-level FQ resistance.

کلیدواژه ها:

Enterobacteriaceae ، DNA Gyrase ، Quinolone resistance