Phenotypic and Genotypic Evaluation of Resistance to Fluoroquinolones in Klebsiella pneumoniae Collected from Hospitalized Patients in Sari, Iran

Antibiotic resistance of Klebsiella pneumoniae to quinolones is a serious concern in treatment of nosocomial infections. There are limited reports on the prevalence of plasmid-mediated quinolone resistance genes in K. pneumoniae clinical isolates from Iran. The aim of this study was to investigate the rate of resistance to fluoroquinolone antibiotics, and also the frequency of qnrA, qnrB, and qnrS genes among K. pneumoniae isolates collected from hospitalized patients in Sari, Iran.

In this descriptive cross-sectional study, bacterial isolates were identified by conventional methods and biochemical tests. Resistance to fluoroquinolone antibiotics was evaluated by disk diffusion method. After resistance assessment, amplification of qnrA, qnrB, and qnrS genes in isolates was performed by polymerase chain reaction (PCR).

We analyzed 90 isolates and the antibiotic resistance of fluoroquinolone included: nalidixic acid (55%), ciprofloxacin (36%), ofloxacin (31%), levofloxacin (29%), and norfloxacin (22%). The PCR showed that 47 (52%), 22 (25%), and 21(23%) isolates harbored qnrB, qnrA, and qnrS genes, respectively.

The outbreak of plasmid-mediated quinolone resistance (PMQR) leads to expand and increases bacterial resistance to fluoroquinolones. Therefore, continuous monitoring of antibiotic sensitivity patterns of K. pneumoniae strains to these agents is necessary.