Double Copies of bla(KPC-3)::Tn4401a on an IncX3 Plasmid in Klebsiella pneumoniae Successful Clone ST512 from Italy

Abstract

A carbapenem-resistant sequence type 512 (ST512) Klebsiella pneumoniae carbapenemase 3 (KPC-3)-producing K. pneumoniae strain showing a novel variant plasmid content was isolated in Palermo, Italy, in 2014. ST512 is a worldwide successful clone associated with the spread of bla(KPC) genes located on the IncFIIk pKpQIL plasmid. In our ST512 strain, the bla(KPC-3) gene was unusually located on an IncX3 plasmid, whose complete sequence was determined. Two copies of bla(KPC-3)::Tn4401a caused by intramolecular transposition events were detected in the plasmid.

FIG 1

Major structural features of plasmids p45, pKpS90, and pIncX-SHV. Predicted open reading frames (ORFs) on plasmids are represented by white arrows. The ORFs of p45 were identified in this study; the ORFs of pKpS90 and pIncX-SHV were deduced from GenBank accession numbers JX461340 and JN247852, respectively. The transposase genes of the Tn44011a transposons flanked by IRR and IRL (thick black lines) are indicated by gray arrows; the bla_KPC-3 genes inside Tn4401a are indicated by black arrows. The DNA sequences of duplicated target sites are indicated above the IRR and IRL. The ygbK, IS3000, and topB genes targeted by Tn4401a transposition events that occurred in the different plasmids are indicated by arrows filled with stripes, dots, and black squares, respectively.