Detection of the new metallo-β-lactamase VIM-19 along with KPC-2, CMY-2 and CTX-M-15 in klebsiella pneumoniae

Abstract

Objectives: To report the identification of the metallo-β-lactamase (MBL) variant VIM-19 in a Klebsiella pneumoniae clinical strain co-producing KPC-2 carbapenemase, CMY-2 cephalosporinase and CTX-M-15 extended-spectrum β-lactamase. Methods: MICs were determined by agar dilution. Phenotypic tests were performed to detect carbapenemase production. PCR and nucleotide sequencing were used for the identification of bla gene types and mapping of the integron carrying the MBL gene. The location of the MBL and KPC alleles was investigated by mating experiments, plasmid analysis and PCR assays. Results: Imipenem, meropenem and ertapenem MICs for the study strain were 32, 16 and 64 mg/L, respectively. The strain carried blaTEM-1, blaCMY-2, blaKPC-2 and blaCTX-M-15 genes along with the gene blaVIM-19, which was located in a class 1 integron as the first gene cassette, followed by aacA6, dfrA1 and aadA1 cassettes. Mating experiments, plasmid analysis and PCR assays revealed that blaVIM-19 and blaCMY-2 were carried on an ~150 kb self-transferable plasmid, while blaKPC-2 and blaTEM-1 were on an ~70 kb self-transferable plasmid; blaCTX-M-15 was non-transferable. Conclusions: The detection of the new MBL, VIM-19, which has enhanced carbapenemase activity, along with KPC-2, CMY-2 and CTX-M-15 is of concern. Further spread of the respective strains or plasmids may have serious consequences for antimicrobial chemotherapy. © The Author 2010.