Abstract
Background: This study aimed to define prevalence of qnr genes and antibiotic susceptibility patterns among clinical isolates of K. pneumoniae in Lorestan province, west of Iran. Methods: Totally, 107 K. pneumoniae isolates were randomly collected since December until September 2012 from hospitalized patients at general hospitals in Lorestan, Iran. The isolates were from different clinical samples including urine, sputum, etc. Biochemical characterizations were performed for detecting isolates. Antibiotic susceptibility testing by disk diffusion method was performed according to recommendations of Clinical and Laboratory Standards Institute using 12 antibiotic disks. K. pneumonia isolates were screened by multiplex PCR amplification of qnrA, qnrB and qnrS using specific primers and sequence analysis of amplified regions of the isolates was also performed. Results: 43 (40.2%) out of 107 isolates were multidrug-resistant (MDR). Ciprofloxacin (Quinolone) susceptibility testing showed that 34 isolates were resistant, 7 isolates were intermediately resistant and 66 isolates were sensitive. 18 (16.8%) out of 107 K. pneumoniae clinical isolates were positive for qnr gene. Among all the qnr-positive isolates, 16 isolates (88.9%) carried qnrB, 1 isolate (5.55%) carried qnrS and the rest (5.55%) carried both qnrB and qnrS genes while no qnrA was detected in these clinical isolates. qnr determinants were detected in 8 (23.5%) of the ciprofloxacin-resistant isolates as well as 1 (14.3%) and 9 (13.6%) intermediate and sensitive isolates, respectively. No significant association was observed between ciprofloxacin resistance and presence of qnr genes (P>0.05). Conclusion: Findings of the present study indicated that emergence of qnr determinants contributed to development and spread of quinolone resistance in Iranian isolates of K. pneumonia.
Highlights
Klebsiella pneumonia is an opportunistic pathogen that usually causes hospital and community acquired bacterial infections in humans [1]
Frequency of qnr genes plasmidmediated quinolones resistance (PMQR) associated with the qnr genes in different human clinical enterobacterial isolates was determined first in the USA in 1994 using a K. pneumoniae isolate [9], which was widely reported worldwide [12,13,14,15,16,17,18,19]
Ciprofloxacin (Quinolone) susceptibility testing showed that 34 isolates (31.8%) were resistant, 7 isolates (6.5%) were intermediately resistant and 66 isolates (61.7%) were sensitive. 18 (16.8%) out of 107 K. pneumoniae clinical isolates screened by multiplex PCR, were positive for the qnr gene
Summary
Klebsiella pneumonia (family Enterobacteriaceae) is an opportunistic pathogen that usually causes hospital and community acquired bacterial infections in humans [1]. Mechanisms of plasmidmediated quinolones resistance (PMQR) by qnr genes have been reported [9] These qnr genes (qnrA, qnrB and qnrS) encode proteins of the pentapeptide repeat family that interfere with the action of quinolones on bacterial DNA gyrase and topoisomerase IV [9,10,11]. This study aimed to define prevalence of qnr genes and antibiotic susceptibility patterns among clinical isolates of K. pneumoniae from general hospitals in Lorestan province, west of Iran. This study aimed to define prevalence of qnr genes and antibiotic susceptibility patterns among clinical isolates of K. pneumoniae in Lorestan province, west of Iran
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