A clinical KPC-producing Klebsiella michiganensis strain carrying IncFII/IncFIA (HI1)/IncFIB (K) multiple replicon plasmid.

is an increasingly important bacterial pathogen causing nosocomial infections in clinical patients. In this study, we described the molecular and genomic characteristics of a carbapenem-resistant strain KM166 cultured from a one-month premature baby's blood sample. KM166 showed lower biofilm forming ability in optical density (OD) than NTUH-K2044 (0.271 ± 0.027 vs. 0.595 ± 0.054,  = 0.001), and the median lethal dose (0.684 lg CFU/mL) was lower than strain NTUH-K2044 (6.679 lg CFU/mL). A IncFII/IncFIA(HI1)/IncFIB(K) multiple replicon plasmid in KM166 was identified carrying three replicon types. It has low homology to pMRY09-581ECO_1 and the highest homology similarity to the INcFIA/INcFII(p14)-type plasmid in strain fxq plasmid pB_KPC, suggesting that this multiple replicon plasmid was unlikely to have been transmitted from and probably a transfer of replicon genes from other strains into the INcFIA/INcFII(p14)-type plasmid of KM166 had occurred. Mapping of the gene environment revealed that in KM166 plasmid 3 had high identity and same Tn3-tnpR-IS481- -klcA_1 genomic context structure with strain JKP55, plasmid pKPC-J5501, and -carrying plasmid proved to be autonomously transferred under the help of mobile genetic elements into 600 by plasmid conjugation experiment. In conclusion, we have characterized a strain carrying multi-replicon IncFII/IncFIA(HI1)/IncFIB(K) plasmid and -carrying IncFII(p14)/IncFIA plasmid in this study, which provided insights about the evolutionary diversity of plasmids carried by .