First report of Klebsiella oxytoca strain coproducing KPC-2 and IMP-8 carbapenemases.

The study shows for the first time the presence of the Klebsiella oxytoca strain fp10 coproducing plasmid-mediated KPC-2 and IMP-8 carbapenemases. The strain was obtained from the fecal sample of an inpatient and showed high-level resistance to imipenem and ertapenem (MICs > 32 μg/ml). Conjugation experiments demonstrated the transferability of the carbapenem-resistant determinants. The results of plasmid analysis and Southern hybridization revealed that the bla(KPC-2) gene was located on transferable plasmid pFP10-1 (∼54 kb), whereas the bla(IMP-8) gene was on transferable plasmid pFP10-2 (∼180 kb). Analysis of the genetic environment of these two genes has demonstrated that ISKpn6 and ISKpn8 are involved in the spread of the bla(KPC-2) gene, while the transposable elements IS26, intI1, and tniC might contribute to the dissemination of the bla(IMP-8) gene. The chimera of several transposon-associated elements indicated a novel genetic environment of IMP-type metallo-β-lactamase gene in Enterobacteriaceae from China.