Characterization of a rare bla VIM-4 metallo-ß-lactamase-producing Serratia marcescens clinical isolate in Hungary.

A carbapenem-resistant S. marcescens isolate was recovered from a patient with an inflammed pacemaker inplantation pocket from a Cardiac Surgery ward in a Hungarian University Hospital. Phenotypic tests and polymerase chain reaction (PCR) confirmed a very rare gene responsible for production of a carbapenemase ( bla VIM-4 ), which was further characterized by Sanger-sequencing. The characterization of this S. marcescens strain emphasizes the ongoing emergence of novel or rare carbapenemases. Strains expressing a weak carbapenemase like this strain might go unrecognized by routine diagnostics due to low minimum inhibitory concentrations (MICs) for the bacterial strains producing such enzymes.