Relative frequency of mutation in QRDR (quinolone resistance determining region) among ciprofloxacin-resistant and susceptible pseudomonas aeruginosa strain isolated from burns of hospitalized patients in Rasht Valayet Hospital in 2018

Introduction and Objective: Pseudomonas aeruginosa is one of the most common opportunistic pathogens which cause death in the patients with burn wounds infection. Fluoroquinolones such as ciprofloxacin could prevent DNA replication of bacterial agents via inhibiting DNA gyrase and topoisomerase IV. The main mechanism of resistance to floroqinolones in p. aeruginosa is alterations in quinolone resistance determining regions (QRDR) of gyrA and parC genes. The aim of present study was to find out the role of these mutations in ciprofloxacin resistant strain. Materials and Methods: 118 isolates of P. aeruginosa were collected from Rasht Valayet Hospital. Afterward isolates were analyzed for antimicrobial susceptibility, polymerase chain reaction amplification of quinolone resistance determining regions (QRDR), finally mutation detection with sequencing. Results: 54 isolates were resistant to ciprofloxacin Thr-83→Ile substitution in the (QRDR) of gyrA was found in ciprofloxacin resistant isolates. Ser-87→Leu substitution in parC was observed. All parC mutations were observed in isolates which carried a gyrA mutation. Conclusion: It was found that mutation in gyrA and parC genes might involve in resistance to ciprofloxacin of P. aeruginosa isolates.

Keywords:

Pseudomonas aeruginosa , Antibiotic Resistance , QRDR