title: Updated molecular epidemiology of carbapenem-non-susceptible Escherichia coli in Taiwan: first identification of KPC-2 or NDM-1-producing E. coli in Taiwan.
abstract: BACKGROUND
  The global spread and increasing incidence of carbapenem-resistant Enterobacteriaceae have resulted in treatment and public health concerns. Here, we present an investigation of the molecular mechanisms and clonality of carbapenem-non-susceptible Escherichia coli (CnSEC) based on a nationwide survey in Taiwan.
  
  
  METHODS
  We collected 32 and 43 carbapenem-non-susceptible E. coli isolates in 2010 and 2012, respectively. The genes encoding cabapenemases and plasmidic AmpC-type and extended-spectrum β-lactamases (EBSLs) were analyzed by polymerase chain reaction (PCR). The major porin channels OmpF and OmpC were evaluated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). Molecular typing was performed with pulsed-field gel electrophoresis (PFGE) and multi-locus sequence typing (MLST).
  
  
  RESULTS
  The resistance rates of CnSEC isolates to cefazolin, cefotaxime, cefoxitin, ceftazidime, and ertapenem were all 100%, and most (94.7%) isolates were CMY producers. The main mechanism of CnSEC in Taiwan is via plasmidic AmpC β-lactamase CMY-2 and DHA-1 in combination with the loss of OmpC/F. In 2010, one isolate was confirmed to harbor blaIMP-8; a KPC-2 producer and an NDM-1 producer were detected in 2012. No isolate had VIM- or OXA-carbapenemases. ST131 was the predominant ST type (33.3%). PFGE revealed no large cluster in CnSEC isolates in Taiwan.
  
  
  CONCLUSIONS
  The co-existence of plasmidic AmpC β-lactamase and outer membrane protein loss is the main mechanism for CnSEC in Taiwan. The emergence of KPC-2 and NDM-1 in 2012 and the predominance of ST131 warrant close monitoring and infection control.
authors.forename: Ling
authors.initials: L
authors.lastname: Ma
authors.forename: L Kristopher
authors.initials: LK
authors.lastname: Siu
authors.forename: Jung-Chung
authors.initials: JC
authors.lastname: Lin
authors.forename: Tsu-Lan
authors.initials: TL
authors.lastname: Wu
authors.forename: Chang-Phone
authors.initials: CP
authors.lastname: Fung
authors.forename: Jann-Tay
authors.initials: JT
authors.lastname: Wang
authors.affiliation: Department of Internal Medicine, Kaohsiung Medical University Hospital, 100 Tzyou 1st Road, Kaohsiung City, Taiwan. d830166@cc.kmu.edu.tw.
authors.forename: Po-Liang
authors.initials: PL
authors.lastname: Lu
authors.forename: Yin-Ching
authors.initials: YC
authors.lastname: Chuang
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D015780:Carbapenems / Q000494:pharmacology*; D024881:Drug Resistance, Bacterial; D004926:Escherichia coli / Q000187:drug effects / Q000201:enzymology* / Q000235:genetics / Q000302:isolation & purification*; D004927:Escherichia coli Infections / Q000453:epidemiology / Q000382:microbiology*; D029968:Escherichia coli Proteins / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D008826:Microbial Sensitivity Tests; D017720:Molecular Epidemiology; D008969:Molecular Sequence Data; D058885:Multilocus Sequence Typing; D010802:Phylogeny; D013624:Taiwan / Q000453:epidemiology; D001618:beta-Lactamases / Q000235:genetics / Q000378:metabolism*
chemical_list: D000900:Anti-Bacterial Agents; D015780:Carbapenems; D029968:Escherichia coli Proteins; C491478:beta-lactamase KPC-2; D001618:beta-Lactamases; C552864:beta-lactamase NDM-1