First identification of an IMI-1 carbapenemase-producing colistin-resistant Enterobactercloacae in China

[摘要] BackgroundCarbapenem resistance among the Enterobacteriaceae is a serious healthcare challenge. blaIMI is a carbapenemase gene mediating resistance to carbapenems but has not been commonly found. A blaIMI-carrying Enterobactercloacae, which was also resistant to colistin, is reported here.FindingsE. 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 blaIMI-1, which has two silent mutations compared to the original blaIMI-1 variant, was found in strain WCHECl-1060. Conjugation and transformation experiments failed to transfer blaIMI-1, suggesting a likely chromosome origin.ConclusionsTo 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.

[发布日期] 2015-11-25

[关键词] β-Lactamases;Carbapenemases;Resistance plasmids;bla;Enterobacter cloacae