Emergence of Carbapenem-Resistant Enterobacter cloacae Carrying VIM-4 Metallo- β -Lactamase and SHV-2a Extended-Spectrum β -Lactamase in a Conjugative Plasmid

Enterobacter cloacae strains are still infrequently resistant to carbapenems. A carbapenem-resistant clinical isolate of E. cloacae producing a plasmid-mediated metallo-β-lactamase (MBL), VIM-4, was recovered from a Greek hospitalized patient. The bla_VIM-4 gene was located in the variable array of a class 1 integron structure repeatedly detected among bla_VIM-1-bearing Gram-negative pathogens in Greece. The isolate possessed also on the same conjugative plasmid an extended-spectrum β-lactamase (ESBL), SHV-2a, which contributed to the β-lactam-resistant phenotype. This is the first report showing co-transfer of an ESBL with a VIM-type MBL. It suggests also that different VIM-type gene cassettes have been incorporated in a common integron structure, which seems indigenous of Gram-negative pathogens in our region.