Plasmid Mediated Fluoroquinolone Resistance Determinants in Clinical Isolates of Escherichia coli
Publisher: IJAMHR, Category: Current Issues
Introduction: Fluoroquinolones are among the most commonly prescribed antimicrobials because of their broad-spectrum antimicrobial activity. The major mechanisms of fluoroquinolones resistance are plasmid mediated quinolone resistance. However, fluoroquinolone resistance in gram-positive and gram-negative bacteria has emerged and increased globally.> Aim: The aim of the current study was to investigated the frequency of qnr genes and aac(6')-Ib-cr gene, among the ciprofloxacin resistant clinical isolates of Escherichia coli. Materials and Methods: The study included 150 E. coli clinical isolates. Disc diffusion technique was used to determine the co-resistance to other antimicrobials. Minimum inhibitory concentration (MIC) was determined by agar dilution method for ciprofloxacin. The presences of qnr genes and aac(6')-Ib-cr gene were screened by PCR. Transfer of the plasmids for qnr positives was studied by conjugation assay. Results: The rates of resistance to the other antibiotics were: ampicilin (92%), cefotaxime (89%), piperacillin/tazobactam (64%), imipenem (11%) and amikacin (32%). MIC of ciprofloxacin ranged from 4μg/ml to ≥ 256μg/ml. Twenty-one (14%) isolates harbored qnr genes of which qnrB was detected in 12 (8%) and eight isolates (5.3%) harbored qnrS. In one isolates (0.6%) both qnrA and qnrS co-existed. The acc(6’)-Ib-cr gene was found in 118 (78.6%) isolates. Among 21 qnr determinants 16 (76%) transconjugants were successfully transferred. Conclusion: In our study the prevalence of acc(6’)-Ib-cr gene in E. coli is found to be significant.
VIEW & DOWNLOAD THIS ARTICLE : Click Here