Phenotypic and genotypic investigation of fluoroquinolones resistance in Klebsiella pneumoniae clinical isolates in Bushehr province, Iran

BACKGROUND AND OBJECTIVESThe emergence of antimicrobial resistance is one of the main global health problems, and the alarming spread of microorganisms resistant to antimicrobial drugs is considered a serious threat. The aim of this study was to investigate the phenotypic and genotypic fluoroquinolones resistance in Klebsiella pneumoniae clinical isolates in Bushehr province, Iran.MATERIALS AND METHODSA total of ۲۱۵ of K. pneumoniae isolates collected from six hospitals in Bushehr province during ۲۰۱۷-۲۰۱۹ were used. Antimicrobial susceptibility test for fluoroquinolones was determined by disk diffusion and E-test methods. The presence of plasmid mediated quinolone resistance (PMQR) genes including qnrA, qnrB, qnrC, qnrD, qnrS, OqxA, aac (۶ʹ)-Ib-cr, and qepA was detected by PCR method. In addition, mutations in gyrA and parC genes in ciprofloxacin-resistant K. pneumoniae isolates were identified by PCR and sequencing.RESULTS AND DISCUSSIONOut of ۲۱۵ K. pneumoniae isolates, ۴۹ isolates (۲۲.۷%) were resistant to ciprofloxacin in disc diffusion method. Among ۴۹ ciprofloxacin-resistant isolates, ۴۰ isolates were resistant by E-test. MIC to ciprofloxacin ranged from ۴μg/ml to ≥۳۲ μg/ml. In addition, PCR results revealed that among ۴۰ ciprofloxacin-resistant isolates, ۱۳ isolates (۳۲.۵%), ۷ isolates (۱۷.۵%), ۴۰ isolates (۱۰۰%) and, ۲۵ isolates (۶۲.۵%) harbored qnrB, qnrS, oqxA and aac(۶ʹ)-Ib-cr genes, respectively. In this study qepA, qnrC, qnrD and qnrA genes were not found. Mutation analysis of gyrA and parC genes showed that out of ۴۰ ciprofloxacin-resistant isolates, ۳۵ (۸۷.۵%) and ۳۴ isolates (۸۵%) had mutations in gyrA and parC gene, respectively. The most mutations were observed in codon ۸۰ of gyrA and codon ۸۳ of parC gene.CONCLUSIONDespite the presence of PMQR genes, mutations in the chromosomal genes play a major role in the occurrence of fluoroquinolone resistance among K. pneumoniae clinical isolates in Bushehr province .

کلیدواژه ها:

Klebsiella pneumoniae ، Quinolone ، Mutation ، parC ، gyrA ، PMQR