title: Characterization of IncF plasmids carrying the blaCTX-M-14 gene in clinical isolates of Escherichia coli from Korea.
abstract: OBJECTIVE
  The purpose of this study was to investigate the molecular epidemiology of CTX-M-14-producing Escherichia coli clinical isolates from Korea.
  
  
  METHODS
  A total of 138 non-duplicate E. coli clinical isolates showing reduced susceptibility or resistance to ceftazidime and/or cefotaxime were included in the study. Resistance genes, genetic environment, R plasmid size and replicon type, sequence type (ST) and XbaI-macrorestriction patterns were determined.
  
  
  RESULTS
  Among 138 isolates, 35 were found to carry the bla(CTX-M-14) gene. The ISEcp1 element was identified in the upstream region of the bla(CTX-M-14) gene in 32 isolates. The bla(CTX-M-14) gene was located on an IncF plasmid in 21 isolates, on an IncA/C plasmid in 1 isolate, on the chromosome in 8 isolates and on both the chromosome and an IncF plasmid in 5 isolates. The most prevalent ST was ST405 (n = 8), followed by ST354 (n = 4), ST38 (n = 3), ST69 (n = 3) and the intercontinental ST, ST131 (n = 3). PFGE and multilocus sequence typing experiments demonstrated no major clonal relationship among the CTX-M-14-producing isolates.
  
  
  CONCLUSIONS
  The bla(CTX-M-14) gene was probably mobilized by IncF plasmids, which can readily spread in E. coli, causing horizontal dissemination of the resistance gene in Korea.
authors.affiliation: Department of Laboratory Medicine and Research Institute of Bacterial Resistance, Yonsei University College of Medicine, Seoul, Korea.
authors.forename: Juwon
authors.initials: J
authors.lastname: Kim
authors.forename: Il Kwon
authors.initials: IK
authors.lastname: Bae
authors.forename: Seok Hoon
authors.initials: SH
authors.lastname: Jeong
authors.forename: Chulhun L
authors.initials: CL
authors.lastname: Chang
authors.forename: Chae Hoon
authors.initials: CH
authors.lastname: Lee
authors.forename: Kyungwon
authors.initials: K
authors.lastname: Lee
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology; D015373:Bacterial Typing Techniques; D002439:Cefotaxime / Q000494:pharmacology; D002442:Ceftazidime / Q000494:pharmacology; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D015252:Deoxyribonucleases, Type II Site-Specific / Q000378:metabolism; D004926:Escherichia coli / Q000145:classification / Q000201:enzymology* / Q000235:genetics / Q000302:isolation & purification*; D004927:Escherichia coli Infections / Q000453:epidemiology* / Q000382:microbiology*; D022761:Gene Transfer, Horizontal; D007723:Korea / Q000453:epidemiology; D017720:Molecular Epidemiology; D008969:Molecular Sequence Data; D058889:Molecular Typing; D010957:Plasmids; D012150:Polymorphism, Restriction Fragment Length; D017422:Sequence Analysis, DNA; D018440:beta-Lactam Resistance; D001618:beta-Lactamases / Q000235:genetics*
chemical_list: D000900:Anti-Bacterial Agents; D004269:DNA, Bacterial; D002442:Ceftazidime; C025580:endodeoxyribonuclease XBAI; D015252:Deoxyribonucleases, Type II Site-Specific; C456080:beta-lactamase CTX-M-14; D001618:beta-Lactamases; D002439:Cefotaxime