title: Molecular analysis of ciprofloxacin resistance mechanisms in Malaysian ESBL-producing Klebsiella pneumoniae isolates and development of mismatch amplification mutation assays (MAMA) for rapid detection of gyrA and parC mutations.
abstract: Ninety-three Malaysian extended-spectrum β-lactamase (ESBL)-producing Klebsiella pneumoniae isolates were investigated for ciprofloxacin resistance. Two mismatch amplification mutation (MAMA) assays were developed and used to facilitate rapid detection of gyrA and parC mutations. The isolates were also screened for plasmid-mediated quinolone resistance (PMQR) genes including aac(6')-Ib-cr, qepA, and qnr. Ciprofloxacin resistance (MICs 4- ≥ 32  μ g/mL) was noted in 34 (37%) isolates, of which 33 isolates had multiple mutations either in gyrA alone (n = 1) or in both gyrA and parC regions (n = 32). aac(6')-Ib-cr was the most common PMQR gene detected in this study (n = 61), followed by qnrB and qnrS (n = 55 and 1, resp.). Low-level ciprofloxacin resistance (MICs 1-2  μ g/mL) was noted in 40 (43%) isolates carrying qnrB accompanied by either aac(6')-Ib-cr (n = 34) or a single gyrA 83 mutation (n = 6). Ciprofloxacin resistance was significantly associated with the presence of multiple mutations in gyrA and parC regions. While the isolates harbouring gyrA and/or parC alteration were distributed into 11 PFGE clusters, no specific clusters were associated with isolates carrying PMQR genes. The high prevalence of ciprofloxacin resistance amongst the Malaysian ESBL-producing K. pneumoniae isolates suggests the need for more effective infection control measures to limit the spread of these resistant organisms in the hospital.
authors.affiliation: Department of Medical Microbiology, Faculty of Medicine, University of Malaya, 50603 Kuala Lumpur, Malaysia.
authors.forename: Farah
authors.identifier: 0000-0001-5711-6264
authors.initials: F
authors.lastname: Al-Marzooq
authors.affiliation: Department of Medical Microbiology, Faculty of Medicine, University of Malaya, 50603 Kuala Lumpur, Malaysia.
authors.forename: Mohd Yasim
authors.initials: MY
authors.lastname: Mohd Yusof
authors.affiliation: Department of Medical Microbiology, Faculty of Medicine, University of Malaya, 50603 Kuala Lumpur, Malaysia.
authors.forename: Sun Tee
authors.initials: ST
authors.lastname: Tay
mesh_terms: D000900:Anti-Bacterial Agents / Q000008:administration & dosage; D020137:Base Pair Mismatch / Q000235:genetics; D001483:Base Sequence; D002470:Cell Survival / Q000187:drug effects / Q000235:genetics; D002939:Ciprofloxacin / Q000008:administration & dosage*; D027081:DNA Gyrase / Q000235:genetics*; D004252:DNA Mutational Analysis / Q000379:methods*; D027101:DNA Topoisomerase IV / Q000235:genetics*; D007711:Klebsiella pneumoniae / Q000187:drug effects* / Q000201:enzymology / Q000235:genetics*; D008296:Malaysia; D008969:Molecular Sequence Data; D009154:Mutation / Q000235:genetics; D021141:Nucleic Acid Amplification Techniques / Q000379:methods; D018440:beta-Lactam Resistance; D001618:beta-Lactamases / Q000378:metabolism*
chemical_list: D000900:Anti-Bacterial Agents; D002939:Ciprofloxacin; D001618:beta-Lactamases; D027101:DNA Topoisomerase IV; D027081:DNA Gyrase