Emergence of Raoultella ornithinolytica Coproducing IMP-4 and KPC-2 Carbapenemases in China

We report here the emergence of seven IMP-4-producing Raoultella ornithinolytica isolates obtained from one patient. All isolates carried the bla IMP-4 carbapenemase gene, five isolates also carried bla SHV-12 , four contained bla TEM-1 , and one contained bla OXA-1 . Notably, the R. ornithinolytica isolate Ro25724 also expressed Klebsiella pneumoniae carbapenemase (KPC)-2. The bla KPC-2 gene was located on a Tn 3 -Tn 4401 integration structure on a plasmid of ∼450 kb. This is the first description of the coexistence of bla KPC-2 and bla IMP-4 from the genus Raoultella .