Emergence of Escherichia coli sequence type 410 (ST410) with KPC-2 β-lactamase

Abstract

Fifteen carbapenem-non-susceptible Escherichia coli isolates obtained during the period May 2010 to April 2011 in a hospital and a long-term care facility (LTCF) in Larissa (Central Greece) were investigated. Minimum inhibitory concentrations (MICs) to various antimicrobial agents were determined by Etest. Carriage of bla genes, including bla(KPC-2) and bla(CTX-M), was documented by polymerase chain reaction (PCR) and sequencing. Production of β-lactamases was confirmed by isoelectric focusing. Transfer of resistance was carried out by conjugation. Plasmid incompatibility groups were determined by PCR-based replicon typing and replicon sequence typing. Isolates were genotyped by multilocus sequence typing. Ten E. coli isolates with KPC-2 were derived from seven patients in the University Hospital of Larissa. Six patients had previously been treated for prolonged time periods in a LTCF located in the same city. The remaining isolate was from a patient previously treated in an Athens hospital. Screening of faecal samples from 20 randomly selected LTCF patients yielded eight enterobacteria with KPC-2, of which five were E. coli, showing the wide spread of KPC-2-producers in this institution and confirming that it was the focus of the outbreak. Fourteen of the isolates were classified as sequence type 410 (ST410); the remaining isolate belonged to a novel ST (ST2281). All 15 isolates carried a KPC-2-encoding plasmid of the Inc group FIIK. Additional plasmids encoding enzymes of the CTX-M-1 family were identified in 11 isolates. The bla(KPC-2)-carrying plasmid IncFIIK, widespread amongst Klebsiella pneumoniae in Greece, has probably been acquired by E. coli ST410 known to be associated with CTX-M production. Diffusion of bla(KPC-2) in common pathogens such as E. coli is of concern.