Study of antibiotic resistance genes qnr and Shigella strains isolated from patients admitted to Children's Medical Center, Tehran
Subject Areas : Medical Microbiology
Majid Moghbeli
1
(Assistant Professor, Department of Microbiology, Faculty of Biological Science, Damghan Branch, Islamic Azad University, Damghan, Iran.)
Vahid Behnood
2
(MS.c., Department of Microbiology, Faculty of Biological Science, Damghan Branch, Islamic Azad University, Damghan, Iran.)
Reza Ranjbar
3
(Associate Professor, Molecular Biology Center. Baghiatallah University, Tehran, Iran.)
Keywords: PCR, Antibiotic resistant, Shigella, qnrS gene,
Abstract :
Background and Objectives: Fluoroquinolones are successfully being used for treatment of the infections caused by Shigella and multiple antimicrobiaol resistant strains, as well. Mutations in gyr A and carrying qnr are the main mechanisms of resistance to quinolone in microbial strains. This study was aimed to investigate the presence of qnr resistant genes and to evaluate the antibiotic resistant profile in Shigella strains isolated from patients. Methods and Materials: This study was carried out on 73 Shigella strains isolated from the patients admitted to Mofid’s children medical center, First, the bacteria and strains isolated from the patients were identified based on biochemical and serological tests. The antibiotic resistance profile was determined based on Kirby– Bauer test. The presence of qnr gene was finally determined using PCR reaction. Results: The antibiotic resistance profile showed that 97.2% of the isolates were resistant to at least one antibiotic among 18 antimicrobial agents. The most antibiotic resistance ability belonged to trimetoprim+ sulfametoxasol (94.5%) while the lowest antibiotic resistance were seen in the case of treatment with Ciprofloxacin and ceftizoxime (with 100% sensitivity ratio). Totally, 23 Shigella isolates showed resistance against nalidixic acid. Of these, four samples, belonging toS. flexeneri (2 strains), S. Soneie (1 strain) and S. Boiedie (1 strain) carried qnrS gene. None of qnrA and qnrB genes were detected in the isolated strains. Conclusion: Based on the data, the nalidixic resistance frequency and presence of qnrS gene was significant in these Shigella isolates.