Emergence of a colistin-resistant KPC-2-producing Klebsiella pneumoniae ST258 clone in Hungary

Nine Klebsiella pneumoniae isolates showing non-susceptibility to carbapenems were collected from three centres in the north-eastern region of Hungary. The minimum inhibitory concentrations (MICs) of antibiotics were determined by Etest. The putative production of a carbapenemase was tested by the modified Hodge test. The presence of bla (KPC) genes was verified by polymerase chain reaction (PCR) and sequencing. Furthermore, molecular typing was performed by pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing (MLST). All isolates showed extensively drug-resistant (XDR) phenotype, and of these, eight isolates were highly resistant to colistin. The isolates carried bla (KPC-2), bla (SHV-12), bla (TEM-1) and bla (SHV-11). PFGE analysis of the nine KPC-2-producing Hungarian ST258 K. pneumoniae isolates, two KPC-2-producing Norwegian ST258 isolates and 33 CTX-M-15-producing ST11 isolates revealed the existence of one genetic cluster at an 88% similarity level. The overall results of the PFGE clustering, MLST and the presence of SHV-11 in both ST11 and ST258 suggest that this is the first hyperepidemic clonal complex of multidrug-resistant K. pneumoniae, probably CC258/CC340, possibly undergoing worldwide spread.