LAUSR

OBJECTIVES This study dealt with a detailed genomic characterization of IncR plasmids from China. METHODS Three IncR plasmids p13190-tetA, p02085-tetA and p30860-tetA from clinical isolates of Klebsiella pneumoniae, Enterobacter cloacae and Citrobacter freundii were fully sequenced by high-throughput genome sequencing, and then compared with five previously sequenced IncR plasmids pHN84KPC, pSH-01, pK245, pKPC_P16, and pKPC-LK30. RESULTS These eight IncR plasmids from China possessed conserved IncR backbones composed of repB, parAB, umuCD, retA and resD. Resistance accessory modules integrated into IncR backbones included the MDR regions in p30860-tetA, p02085-tetA, p13190-tetA and pK245, the blaKPC-2 regions in pHN84KPC, pKPC-LK30 and pKPC_P16, and the ΔTn1721-sil region in pSH-01. These resistance accessory modules were inserted at a site between retA and vagD, resulting in loss of backbone genes vagCD in some of these plasmids, and they differed dramatically from one another and carried distinct profiles of resistance makers. In particular, all of p13190-tetA, p02085-tetA and p30860-tetA, and pHN84KPC, pSH-01 and pK245 carried tetracycline-resistance tet gene modules and the carbapenemase gene blaKPC-2 was identified in pHN84KPC, pKPC-LK30 and pKPC_P16. In addition, one or more regions responsible for plasmid replication and/or maintenance were found in some of these resistance accessory modules, facilitating stable replication of corresponding IncR plasmids at steady-state copy numbers. CONCLUSIONS This is a detailed comparative genomics analysis of IncR plasmids from China, providing a deeper insight into diversification and evolution of IncR plasmids.