Detection of clonal KPC-2-producing Klebsiella pneumoniae ST258 in Korea during nationwide surveillance in 2011

This study analysed the characteristics and genetic similarity of recent Klebsiella pneumoniae carbapenemase (KPC-2)-producing Klebsiella pneumoniae isolates from Korea. Recent laboratory surveillance detected an increase in carbapenemase-producing Enterobacteriaceae in Korea. A total of 6 KPC-2-producing K. pneumoniae were identified from 277 Enterobacteriaceae clinical isolates. All were sequence type (ST) 258 and they had the same pulsotype. They had high MICs for carbapenems and multi-drug resistance. TEM-1, SHV-11 and OXA type β-lactamases were detected in all isolates, whereas CTX-M type β-lactamases and plasmid-mediated AmpC β-lactamase (PABL) were not present. A conjugation experiment failed, but blaKPC-2-harbouring plasmids from the six isolates were used to transform Escherichia coli DH5-α by electroporation. Each of the transformants harboured a blaKPC-2-positive approximately 95 kb plasmid, which was typed in the IncFII incompatibility group and co-harboured TEM-1 and OXA-9 β-lactamases. They shared the same restriction profile. This study confirms the emergence of clonal ST258 KPC-2-producing K. pneumoniae in some regions of Korea.