Mix and match of KPC-2 encoding plasmids in Enterobacteriaceae-comparative genomics

We performed comparative sequence analysis of 3 bla(KPC-2) encoding plasmids to examine evolution of these plasmids and their dissemination. We found that all of them have an IncN replicon with a newly determined IncN plasmid sequence type (ST), ST15. The 2 Klebsiella pneumoniae (KPN) plasmids also harbor an IncF2A1-B1- replicon. The bla(KPC-2) is located in the Tn4401c transposon with a newly discovered mutation in the P2 promoter. Screening of the 27 additional bla(KPC-2) carrying plasmids from Enterobacter cloacae, Escherichia coli (EC), and K. pneumoniae showed that: all KPN and EC plasmids are IncN plasmids belonging to ST15; 4/7 KPN and 1/6 EC plasmids contain an additional IncF2A1-B1- replicon; all Enterobacter plasmids belong to neither IncN nor IncF2A1-B1- replicon plasmids; 6/7 KPN and 2/5 EC plasmids carry the mutated P2 promoter. Study of the bla(KPC-2) environment, transposon, pMLST, and Inc group suggests transposon and plasmid inter- and intra-species dissemination and evolution. (C) 2014 Elsevier Inc. All rights reserved.