Molecular characterization of an Escherichia coli clinical isolate that produces both metallo-beta-lactamase VIM-2 and extended-spectrum beta-lactamase GES-7: identification of the In8 integron carrying the blaVIM-2 gene.

OBJECTIVES: We have previously reported the isolation of a VIM-2-producing Escherichia coli clinical isolate and the coexistence of blaVIM-2 and blaGES-7 in the same isolate. The aim of this study was to elucidate the genetic environment of these genes.
METHODS: PCR and sequence analysis were used to identify and analyse the blaVIM-containing integron. The location of the blaVIM-2 and blaGES-7 genes was identified by hybridization experiments on I-CeuI-digested genomic DNA after PFGE.
RESULTS: Only the blaVIM-2 gene has been found on a class I integron, designated In8 (1474 bp). Hybridization with the blaVIM-2, the blaGES-7 and the 16S-23S rRNA probes confirmed the chromosomal location of both genes. The blaVIM-2 probe hybridized with a 710 kb fragment whereas the blaGES-7 probe hybridized with a 144 kb fragment of genomic DNA of the E. coli isolate.
CONCLUSIONS: This report provides evidence for the chromosomal location of both blaVIM-2 and blaGES-7 genes carried by an E. coli clinical isolate. In8, containing blaVIM-2, presents an emerging threat of carbapenem resistance among E. coli isolates in Greece.