Characterization of bla(KPC-2)-Carrying Plasmid pR31-KPC from a Pseudomonas aeruginosa Strain Isolated in China

This work aimed to characterize a 29-kb bla(KPC-2)-carrying plasmid, pR31-KPC, from a multidrug resistant strain of Pseudomonas aeruginosa isolated from the sputum of an elderly patient with multiple chronic conditions in China. The backbone of pR31-KPC is closely related to four other bla(KPC-2)-carrying plasmids, YLH6_p3, p1011-KPC2, p14057A, and pP23-KPC, none of which have been assigned to any of the known incompatibility groups. Two accessory modules, the IS26-bla(KPC-2)-IS26 unit and IS26-ΔTn6376-IS26 region, separated by a 5.9-kb backbone region, were identified in pR31-KPC, which was also shown to carry the unique resistance marker bla(KPC-2). A comparative study of the above five plasmids showed that p1011-KPC2 may be the most complete plasmid of this group to be reported, while pR31-KPC is the smallest plasmid having lost most of its conjugative region. Regions between the iterons and orf207 in the backbone may be hot spots for the acquisition of exogenous resistance entities. The accessory regions of these plasmids have all undergone several biological events when compared with Tn6296. The further transfer of bla(KPC-2) in these plasmids may be initiated by either the Tn3 family or IS26-associated transposition or homologous recombination. The data presented here will contribute to a deeper understanding of bla(KPC-2) carrying plasmids in Pseudomonas.