title: Investigation of mutation distribution in DNA gyrase and topoisomerase IV genes in ciprofloxacin-non-susceptible Enterobacteriaceae isolated from blood cultures in a tertiary care university hospital in South Korea, 2005-2010.
abstract: This study investigated the distribution of mutations in DNA gyrase (gyrA and gyrB) and topoisomerase IV (parC and parE) genes and compared the distribution of these mutations with the distribution of plasmid-mediated quinolone resistance (PMQR) genes and extended-spectrum β-lactamase (ESBL) production in 101 ciprofloxacin-non-susceptible Enterobacteriaceae from blood culture isolates (80 Escherichia coli and 21 Klebsiella pneumoniae) isolated in Kyung Hee University Hospital, a tertiary care university hospital in Seoul, South Korea. Among the 101 isolates, 80 (79.2%) contained PMQR genes and 28 (27.7%) produced ESBL. Mutations in the gyrA and parC genes were observed more frequently than in the gyrB and parE genes as well as more frequently in E. coli than in K. pneumoniae isolates, even in the same ciprofloxacin minimum inhibitory concentration (MIC) range of the two species. In E. coli isolates, the distribution of the codon 529 mutation (Ile→Leu) in parE was increased with an increase in the ciprofloxacin MIC. An increase in high-level resistance to quinolones may occur with double mutations compared with a single mutation in gyrA as well as with additional mutations in parC. However, this finding could not be applied to ciprofloxacin-resistant K. pneumoniae. A higher level of quinolone resistance may be correlated with an additional mutation in parE, especially Ile529→Leu.
authors.affiliation: Department of Biomedical Science, Kyung Hee University Graduate School, Seoul, South Korea.
authors.forename: You Sun
authors.initials: YS
authors.lastname: Nam
authors.forename: Sun Young
authors.initials: SY
authors.lastname: Cho
authors.forename: Hee Young
authors.initials: HY
authors.lastname: Yang
authors.forename: Kyung Sun
authors.initials: KS
authors.lastname: Park
authors.forename: Ji-Hyun
authors.initials: JH
authors.lastname: Jang
authors.forename: Yun-Tae
authors.initials: YT
authors.lastname: Kim
authors.forename: Joo-Won
authors.initials: JW
authors.lastname: Jeong
authors.forename: Jin-Tae
authors.initials: JT
authors.lastname: Suh
authors.forename: Hee Joo
authors.initials: HJ
authors.lastname: Lee
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology; D016470:Bacteremia / Q000382:microbiology*; D002939:Ciprofloxacin / Q000494:pharmacology*; D027081:DNA Gyrase / Q000235:genetics*; D027101:DNA Topoisomerase IV / Q000235:genetics*; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D024881:Drug Resistance, Bacterial; D004755:Enterobacteriaceae / Q000187:drug effects / Q000235:genetics* / Q000302:isolation & purification; D004756:Enterobacteriaceae Infections / Q000382:microbiology; D006785:Hospitals, University; D006801:Humans; D008826:Microbial Sensitivity Tests; D009154:Mutation; D056910:Republic of Korea; D017422:Sequence Analysis, DNA; D062606:Tertiary Care Centers
chemical_list: D000900:Anti-Bacterial Agents; D004269:DNA, Bacterial; D002939:Ciprofloxacin; D027101:DNA Topoisomerase IV; D027081:DNA Gyrase