title: First identification of an IMI-1 carbapenemase-producing colistin-resistant Enterobacter cloacae in China.
abstract: BACKGROUND
  Carbapenem resistance among the Enterobacteriaceae is a serious healthcare challenge. bla IMI is a carbapenemase gene mediating resistance to carbapenems but has not been commonly found. A bla IMI-carrying Enterobacter cloacae, which was also resistant to colistin, is reported here.
  
  
  RESULTS
  E. cloacae strain WCHECl-1060 was recovered from a blood sample of a leukemia patient, who was not previously exposed to colistin. Strain WCHECl-1060 belongs to a new sequence type, ST410, and was resistant to carbapenems and colistin but was susceptible to third-generation cephalosporins. A new allelic variant of bla IMI-1, which has two silent mutations compared to the original bla IMI-1 variant, was found in strain WCHECl-1060. Conjugation and transformation experiments failed to transfer bla IMI-1, suggesting a likely chromosome origin.
  
  
  CONCLUSIONS
  To our knowledge, this is the first report of an IMI-1 carbapenemase-producing colistin-resistant E. cloacae in China. Microbiological laboratories should be aware of the unusual carbapenem-resistant but third-generation cephalosporin-susceptible profiles of these IMI-producing isolates. The trend of colistin resistance among the Enterobacteriaceae should be also monitored.
authors.affiliation: Center of Infectious Diseases, West China Hospital (Huaxi), Sichuan University, Guoxuexiang 37, 610041, Chengdu, China. 15201920@qq.com.|Division of Infectious Diseases, State Key Laboratory of Biotherapy, Chengdu, China. 15201920@qq.com.
authors.forename: Liang
authors.initials: L
authors.lastname: Huang
authors.affiliation: Center of Infectious Diseases, West China Hospital (Huaxi), Sichuan University, Guoxuexiang 37, 610041, Chengdu, China. melodywxh@aliyun.com.|Division of Infectious Diseases, State Key Laboratory of Biotherapy, Chengdu, China. melodywxh@aliyun.com.
authors.forename: Xiaohui
authors.initials: X
authors.lastname: Wang
authors.affiliation: Center of Infectious Diseases, West China Hospital (Huaxi), Sichuan University, Guoxuexiang 37, 610041, Chengdu, China. a1204350@qq.com.|Division of Infectious Diseases, State Key Laboratory of Biotherapy, Chengdu, China. a1204350@qq.com.
authors.forename: Yu
authors.initials: Y
authors.lastname: Feng
authors.affiliation: Laboratory of Clinical Microbiology, Department of Laboratory Medicine, West China Hospital, Sichuan University, Chengdu, China. xie_yi_77@163.com.
authors.forename: Yi
authors.initials: Y
authors.lastname: Xie
authors.affiliation: Department of Haematology, West China Hospital, Sichuan University, Chengdu, China. xielipingyx@163.com.
authors.forename: Liping
authors.initials: L
authors.lastname: Xie
authors.affiliation: Center of Infectious Diseases, West China Hospital (Huaxi), Sichuan University, Guoxuexiang 37, 610041, Chengdu, China. zongzhiy@scu.edu.cn.|Division of Infectious Diseases, State Key Laboratory of Biotherapy, Chengdu, China. zongzhiy@scu.edu.cn.
authors.forename: Zhiyong
authors.initials: Z
authors.lastname: Zong
mesh_terms: D000328:Adult; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D016470:Bacteremia / Q000382:microbiology; D001426:Bacterial Proteins / Q000235:genetics*; D015780:Carbapenems / Q000494:pharmacology; D002681:China; D003091:Colistin / Q000494:pharmacology*; D003227:Conjugation, Genetic; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D024881:Drug Resistance, Bacterial; D016972:Enterobacter cloacae / Q000187:drug effects* / Q000201:enzymology* / Q000235:genetics / Q000302:isolation & purification; D004756:Enterobacteriaceae Infections / Q000382:microbiology*; D006801:Humans; D007938:Leukemia / Q000150:complications; D008297:Male; D008969:Molecular Sequence Data; D058889:Molecular Typing; D017422:Sequence Analysis, DNA; D001618:beta-Lactamases / Q000235:genetics*
chemical_list: D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D015780:Carbapenems; D004269:DNA, Bacterial; D001618:beta-Lactamases; C063912:carbapenemase; D003091:Colistin