title: Replicon sequence typing of IncF plasmids and the genetic environments of blaCTX-M-15 indicate multiple acquisitions of blaCTX-M-15 in Escherichia coli and Klebsiella pneumoniae isolates from South Korea.
abstract: OBJECTIVE
  The purpose of this study was to investigate variations in IncF plasmids and the genetic environments of bla(CTX-M-15) in CTX-M-15-producing Escherichia coli and Klebsiella pneumoniae isolates from South Korea.
  
  
  METHODS
  A total of 56 E. coli and 15 K. pneumoniae isolates, which were previously characterized for CTX-M-15 production, sequence type by multilocus sequence typing and replicon type, were included in this study. Replicon sequence typing for IncF plasmids was performed and the genetic environments of bla(CTX-M-15) were determined using PCR and sequencing.
  
  
  RESULTS
  A total of 34 and 10 IncF-replicon sequence types (RSTs) were identified among the E. coli and K. pneumoniae isolates, respectively. Only eight and four IncF-RSTs were found in multiple isolates of E. coli and K. pneumoniae, respectively. No common IncF-RSTs were found between E. coli and K. pneumoniae isolates. Five and three different bla(CTX-M-15) genetic environments were identified in E. coli and K. pneumoniae isolates, respectively. Even in the same E. coli clone, diverse IncF-RSTs and bla(CTX-M-15) genetic environments were identified.
  
  
  CONCLUSIONS
  Diverse IncF plasmids have incorporated into diverse strains of E. coli and K. pneumoniae, contributing to the spread of the CTX-M-15 extended-spectrum β-lactamase in South Korea. It can also be inferred that bla(CTX-M-15) has not been transferred directly from E. coli to K. pneumoniae.
authors.affiliation: Department of Molecular Cell Biology,  Samsung Biomedical Research Institute, Sungkyunkwan University School of Medicine, Suwon 440-746,  Korea.
authors.forename: Juyoun
authors.initials: J
authors.lastname: Shin
authors.forename: Myung-Jin
authors.initials: MJ
authors.lastname: Choi
authors.forename: Kwan Soo
authors.initials: KS
authors.lastname: Ko
mesh_terms: D004926:Escherichia coli / Q000201:enzymology* / Q000235:genetics* / Q000302:isolation & purification; D004927:Escherichia coli Infections / Q000382:microbiology; D019143:Evolution, Molecular; D014644:Genetic Variation; D005838:Genotype; D006801:Humans; D007710:Klebsiella Infections / Q000382:microbiology; D007711:Klebsiella pneumoniae / Q000201:enzymology* / Q000235:genetics* / Q000302:isolation & purification; D010957:Plasmids; D016133:Polymerase Chain Reaction; D012093:Replicon; D056910:Republic of Korea; D017422:Sequence Analysis, DNA; D001618:beta-Lactamases / Q000235:genetics*
chemical_list: C473109:beta-lactamase CTX-M-15; D001618:beta-Lactamases