The IncP-6 Plasmid p10265-KPC from Pseudomonas aeruginosa Carries a Novel △ISEc33-Associated blaKpc-2 Gene Cluster

Pseudomonas aeruginosa strain 10265 was recovered from a patient with pneumonia in a Chinese public hospital, and it displays the carbapenem resistance phenotype due to the acquisition of a non-conjugative but mobilizable IncP-6-type plasmid p10265-KPC. p10265-KPC carries a Tn5563-borne defective mer locus, and a novel triangle ISEc33-associated bla(Kpc-2) gene cluster without paired inverted repeats and paired direct repeats at both ends. Mobilization of this triangle ISEc33-associated element in p10265-KPC would be attributed to homologous recombination-based insertion of a foreign structure Tn3-ISApu1-orf7-ISApu2- ISKpn27-triangle bla(TEM-1)-bla(Kpc-2)-triangle ISKpn6-korC-orf6-klcA-triangle repB into a pre-existent intact ISEc33, making ISEc33 truncated at the 3' end. The previously reported pCOL-1 represents the first sequenced KPC-producing IncP-6 plasmid, while p10265-KPC is the second one. These two plasmids carry two distinct bla(Kpc-2) gene clusters, which are inserted into the different sites of the IncP-6 backbone and have different evolutionary histories of assembly and mobilization. This is the first report of identification of the IncP-6-type resistance plasmid in China.