Characterization of plasmid-mediated quinolone resistant genes among uropathogenic Escherichia coli isolates in Bushehr, south of Iran.

Objectives: Uropathogenic Escherichia coli (UPEC) is important in urinary tract infection (UTI). Quinolones and fluoroquinolones are broad-spectrum antibiotics for the treatment of UTI, although some of UPEC are resistant to these antibiotics. This study aims to investigate phenotypic and genotypic characterization of plasmid-mediated quinolone resistance UPEC isolated from patients with UTI in Bushehr. In this study, 105 isolates of UPEC were identified by standard microbiological tests and the susceptibility pattern of quinolone and fluoroquinolone were determined by the disc diffusion method. PCR was used to check the presence of plasmid-mediated quinolone resistance genes.

Results: Pattern of antibiotic susceptibility showed that more than 50% and 75% of isolates were resistant to fluoroquinolones and quinolones, respectively. The frequencies of qnrS and qnrB genes were 49.5% and 23.8%, respectively. Based on analysis, there was a significant relationship between the presence of the qnrB gene and resistance to ciprofloxacin, norfloxacin, ofloxacin and levofloxacin. There was a significant relationship between the presence of qnrS gene and resistance to the tested antibiotics. Our results showed a high level of resistance to fluoroquinolones. Therefore, it is necessary to treat and prevent UTI so that physicians can use alternative antibiotics to treatment of patients based on laboratory results.