Further Spread of a bla KPC -Harboring Untypeable Plasmid in Enterobacteriaceae in China.

The wide spread of Klebsiella pneumoniae carbapenemase (KPC)-producing Enterobacteriaceae is great threat to public health in China. Plasmids are among the major factors mediating bla KPC gene dissemination. A total of 156 carbapenem-resistant Enterobacteriaceae (CRE) isolates were identified in a tertiary hospital in China. Six KPC-producing isolates, namely, E. coli ( n = 2), E. asburiae ( n = 1), C. freundii ( n = 1), C. portucalensis ( n = 1), and C. koseri ( n = 1), tested positive for the pCKPC18-1-like untypeable plasmid, which was described recently in C. freundii . All 6 plasmids could be easily transferred into E. coli by chemical transformation or conjugation and were confirmed by sequencing to harbor bla KPC-2 . Multilocus PCRs and EcoRI-RFLP revealed that the 6 untypeable plasmids belonged to 2 isoforms. High-throughput sequencing of representative plasmids (pCP40 and pEC86) led to the identification of 2 plasmids that shared the common backbone genes repA, DnaJ, StpA , and yafB , which were characteristic of the untypeable plasmid, and had similar bla KPC-2 genetic contexts of the Tn 3 -Tn 4401 chimera. Nucleotide comparison revealed high sequence identity of the 2 plasmids with previously reported bla KPC-2 -carrying untypeable plasmids. In particular, the pCP40 plasmid from C. portucalensis and the pHS062105-3 plasmid from K. pneumoniae differed by only 20 single-nucleotide polymorphisms (SNPs). To the best of our knowledge, this is the first report of a bla KPC -harboring untypeable plasmid spread into E. coli, E. asburiae , and C. koseri strains in China.