title: Prevalence of plasmid-mediated quinolone resistance and mutations in the gyrase and topoisomerase IV genes in Salmonella isolated from 12 tertiary-care hospitals in Korea.
abstract: BACKGROUND
  The aim of this study was to investigate the prevalence of plasmid-mediated quinolone resistance (PMQR) and mutations in quinolone resistance-determining regions (QRDRs) of Salmonella and their association with fluoroquinolone susceptibility in Korea.
  
  
  METHODS
  A total of 284 nonduplicated clinical isolates of Salmonella were collected from various clinical specimens at 12 tertiary-care hospitals in Korea. The qnrA, qnrB, and qnrS genes were detected by multiplex polymerase chain reaction (PCR). The qepA and aac(6')-Ib-cr genes were amplified by PCR. The QRDRs of gyrA, gyrB, parC, and parE were amplified by PCR from the DNA of selected nalidixic acid-resistant and qnr-positive isolates.
  
  
  RESULTS
  We detected six qnr-positive Salmonella (four qnrS1 and two qnrB19) and one aac(6')-Ib-cr-positive strain. A mutation in the QRDR of gyrA only (N=46) was the most common, followed by gyrA+parC (N=9), parC (N=7), gyrA+parE (N=3), parC+parE (N=3), gyrA+gyrB (N=2), and parE (N=1). There were seven novel mutations in the QRDR regions of gyrB, parC, and parE. Six of seven PMQR-positive isolates had high-level resistance to nalidixic acid, and all six strains had reduced susceptibility to ciprofloxacin. One qnrS1-positive isolate was resistant to ciprofloxacin, norfloxacin, and nalidixic acid. The resistant rates to nalidixic acid, ciprofloxacin, norfloxacin, and levofloxacin were 49.3%, 1.1%, 0.7%, and 0.4%, respectively.
  
  
  CONCLUSIONS
  We report the first detection of PMQR in Salmonella isolates from Korea. It is essential to continue surveillance and to watch for the spread of PMQR in Salmonella for public health control.
authors.affiliation: Department of Laboratory Medicine, Inje University College of Medicine, 633-165 Gaegeum-dong Busanjin-gu, Busan, Korea.
authors.forename: Haeng Soon
authors.initials: HS
authors.lastname: Jeong
authors.forename: Jeong A
authors.initials: JA
authors.lastname: Kim
authors.forename: Jeong Hwan
authors.initials: JH
authors.lastname: Shin
authors.forename: Chulhun L
authors.initials: CL
authors.lastname: Chang
authors.forename: Joseph
authors.initials: J
authors.lastname: Jeong
authors.forename: Ji-Hyun
authors.initials: JH
authors.lastname: Cho
authors.forename: Mi-Na
authors.initials: MN
authors.lastname: Kim
authors.forename: Sunjoo
authors.initials: S
authors.lastname: Kim
authors.forename: Young Ree
authors.initials: YR
authors.lastname: Kim
authors.forename: Chae Hoon
authors.initials: CH
authors.lastname: Lee
authors.forename: Kyungwon
authors.initials: K
authors.lastname: Lee
authors.forename: Mi Ae
authors.initials: MA
authors.lastname: Lee
authors.forename: Wee Gyo
authors.initials: WG
authors.lastname: Lee
authors.forename: Jong Hee
authors.initials: JH
authors.lastname: Shin
authors.forename: Jeong Nyeo
authors.initials: JN
authors.lastname: Lee
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001426:Bacterial Proteins; D003227:Conjugation, Genetic; D027081:DNA Gyrase / Q000235:genetics*; D027101:DNA Topoisomerase IV / Q000235:genetics*; D024881:Drug Resistance, Bacterial / Q000235:genetics*; D024841:Fluoroquinolones / Q000494:pharmacology; D006785:Hospitals, University; D006801:Humans; D008826:Microbial Sensitivity Tests; D009154:Mutation / Q000235:genetics*; D010957:Plasmids / Q000235:genetics*; D015995:Prevalence; D015363:Quinolones / Q000494:pharmacology*; D056910:Republic of Korea / Q000453:epidemiology; D012475:Salmonella / Q000187:drug effects* / Q000201:enzymology / Q000235:genetics / Q000302:isolation & purification; D012480:Salmonella Infections / Q000453:epidemiology* / Q000382:microbiology; D012486:Salmonella typhimurium / Q000187:drug effects / Q000201:enzymology / Q000235:genetics / Q000302:isolation & purification
chemical_list: D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D024841:Fluoroquinolones; D015363:Quinolones; D027101:DNA Topoisomerase IV; D027081:DNA Gyrase