Molecular characterization of KPC-producing Klebsiella pneumoniae isolated from patients in a Public Hospital in Caracas, Venezuela.

INTRODUCTION: Klebsiella pneumoniae carbapenemase (KPC)-producing bacteria are amongst the most important causative agents of nosocomial infections worldwide. Isolates of this bacterium have been identified in Venezuela but little is known about their local spread. The aim of this study was to perform the molecular characterization of KPC-producing strains isolated from 2012 to 2013 in a public hospital in Caracas, Venezuela.

METHODS: Twenty-two K. pneumoniae clinical isolates phenotypically classified as KPC producing were subjected to PCR screening for the presence of blaKPC genes and their location within transposon Tn4401. The blaKPC PCR product was sequenced to identify the KPC alleles. Genotypic analysis was performed by means of repetitive extragenic palindromic PCR (rep-PCR) and Multi Locus Sequence Typing (MLST). Finally, conjugation and electroporation assays were used to determine whether the blaKPC genes were found in plasmids.

RESULTS: All isolates contained the blaKPC-2 variant, and 21 of the 22 were associated with the Tn4401b isoform. The strains were distributed in 8 sequence types (ST), three of which were new. Conjugation and electroporation assays indicated that 95.5% (n=21/22) of the isolates contained the blaKPC gene in plasmids.

CONCLUSIONS: This study on circulating bacterial strains and the identification of KPC alleles may help to understand the routes of dissemination and control their spread within this hospital.