title: The emergence of blaCTX-M-15-carrying Escherichia coli of ST131 and new sequence types in Western China.
abstract: BACKGROUND
  blaCTX-M-15, the most widely distributed gene encoding extended-spectrum β-lactamases globally, was not common in China. This study was performed to characterize blaCTX-M-15-carrying Escherichia coli in western China.
  
  
  RESULTS
  Out of 144 Escherichia coli isolates from 20 hospitals in western China, 8 were found carrying blaCTX-M-15. blaCTX-M-15 was carried by isolates of ST131and 5 new STs (ST3342, ST3513, ST3516, ST3517 and ST3518). The 5 new STs shared 5 identical alleles out of 7 but only had up to 2 alleles identical to ST131. blaCTX-M-15 was located on plasmids of IncI1 (ST16) or IncFII-related group (four replicon types). The co-transfer of a few antimicrobial resistance genes including qnrA, qnrB, qnrS, qepA, aac (6')-Ib-cr, aac (3)-II, tetA, blaTEM and blaOXA-1 with blaCTX-M-15 were examined but only blaTEM-1 was found co-transferring with blaCTX-M-15.
  
  
  CONCLUSIONS
  Five new STs of E. coli and three new types of IncFII-related plasmids carrying blaCTX-M-15 were identified. This study together with several reports suggested that blaCTX-M-15 has emerged in China and the interruption of both vertical and horizontal transmission of blaCTX-M-15 is required to hurdle its further spread.
authors.affiliation: Center of Infectious Diseases, West China Hospital, Sichuan University, Guoxuexiang 37, Chengdu 610041, China. zongzhiy@scu.edu.cn.
authors.forename: Lei
authors.initials: L
authors.lastname: Zhang
authors.forename: Xiaoju
authors.initials: X
authors.lastname: Lü
authors.forename: Zhiyong
authors.initials: Z
authors.lastname: Zong
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology; D002681:China; D021821:Communicable Diseases, Emerging / Q000188:drug therapy / Q000382:microbiology*; D004926:Escherichia coli / Q000187:drug effects* / Q000235:genetics / Q000302:isolation & purification; D004927:Escherichia coli Infections / Q000188:drug therapy / Q000382:microbiology*; D005798:Genes, Bacterial; D006801:Humans; D018440:beta-Lactam Resistance / Q000235:genetics*; D001618:beta-Lactamases / Q000235:genetics*; D047090:beta-Lactams / Q000494:pharmacology / Q000627:therapeutic use
chemical_list: D000900:Anti-Bacterial Agents; D047090:beta-Lactams; C473109:beta-lactamase CTX-M-15; D001618:beta-Lactamases