Outbreak caused by a multidrug-resistant Klebsiella pneumoniae clone carrying blaVIM-12 in a university hospital.

From November 2006 to April 2007, nine nonrepetitive isolates of Klebsiella pneumoniae with reduced susceptibility or resistance to carbapenems were recovered from clinical specimens from separate patients hospitalized in a tertiary care hospital. The imipenem-EDTA synergy test was positive for all isolates. PCR, sequencing, and transferability experiments revealed the novel bla(VIM-12) metallo-beta-lactamase gene, which was plasmid mediated and located in a class 1 integron. Pulsed-field gel electrophoresis demonstrated a single macrorestriction pattern, indicating the clonal spread of VIM-12-producing K. pneumoniae.