Comparative analysis of bla (KPC-2)- and rmtB-carrying IncFII-family pKPC-LK30/pHN7A8 hybrid plasmids from Klebsiella pneumoniae CG258 strains disseminated among multiple Chinese hospitals

BACKGROUND: We recently reported the complete sequence of a blaKPC-2- and rmtB-carrying IncFII-family plasmid p675920-1 with the pKPC-LK30/pHN7A8 hybrid structure. Comparative genomics of additional sequenced plasmids with similar hybrid structures and their prevalence in bla(KPC)-carrying Klebsiella pneumoniae strains from China were investigated in this follow-up study. METHODS: A total of 51 bla(KPC)-carrying K. pneumoniae strains were isolated from 2012 to 2016 from five Chinese hospitals and genotyped by multilocus sequence typing. The bla(KPC)-carrying plasmids from four representative strains were sequenced and compared with p675920-1 and pCT-KPC. Plasmid transfer, carbapenemase activity determination, and bacterial antimicrobial susceptibility test were performed to characterize resistance phenotypes mediated by these plasmids. The prevalence of pCT-KPC-like plasmids in these bla(KPC)-carrying K. pneumoniae strains was screened by PCR. RESULT: The six KPC-encoding plasmids p1068-KPC, p20049-KPC, p12139-KPC and p64917-KPC (sequenced in this study) and p675920-1 and pCT-KPC slightly differed from one another due to deletion and acquisition of various backbone and accessory regions. Two major accessory resistance regions, which included the blaKPC-2 region harboring blaKPC-2 (carbapenem resistance) and blaSHV-12 (β-lactam resistance), and the MDR region carrying rmtB (aminoglycoside resistance), fosA3 (fosfomycin resistance), bla(TEM-1B) (β-lactam resistance) and bla(CTX-M-65) (β-lactam resistance), were found in each of these six plasmids and exhibited several parallel evolution routes. The pCT-KPC-like plasmids were present in all the 51 K. pneumoniae isolates, all of which belonged to CG258. CONCLUSION: There was clonal dissemination of K. pneumoniae CG258 strains, harboring bla(KPC-2)- and rmtB-carrying IncFII-family pKPC-LK30/pHN7A8 hybrid plasmids, among multiple Chinese hospitals.