KPC-3 Carbapenemase Harbored in FIIk Plasmid from Klebsiella pneumoniae ST512 and Escherichia coli ST43 in the Same Patient

Five carbapenem-resistant strains (three Klebsiella pneumoniae, one Escherichia coli, and one Enterobacter aerogenes) were isolated between 2009 and 2012 at the Verona University Hospital, Italy, during an epidemiological analysis of antibiotic resistance determinants and plasmid profiles in Enterobacteriaceae. Two out of the five strains, K. pneumoniae E530 and E. coli E558, were cultured from bile and abdominal drainage, respectively, of a single patient. The strains were resistant to beta-lactams and fluoroquinolones, and susceptible to tigecycline and colistin. All the strains harboured blaKPC-3, blaTEM-1, and blaOXA-9, and the three K. pneumoniae additionally carried blaSHV-11 and aac(6')Ib. The blaKPC-3 was inserted in transposon Tn4401a. All the strains hosted an FIIk-type plasmid, and the three K. pneumoniae coharboured an colE-type plasmid. Transconjugants, besides blaKPC-3, harboured blaTEM-1 and blaOXA-9 genes on FIIk-type plasmid. K. pneumoniae E301 was ST258, while strain E530 and C525 belonged to the ST512, and E. coli E558 was ST43. To our best knowledge, this is the first report that strongly supports the transmission of blaKPC-3 from ST512 K. pneumoniae to E. coli ST43 in a single patient, a phenomenon of both clinical and microbiological importance.