Molecular characterization of Klebsiella pneumoniae carbapenemase-producing isolates in southern Brazil.

Carbapenem-resistant Enterobacteriaceae have been frequently reported worldwide. They represent a serious concern because of the limited therapeutic options. The aim of this study was to investigate the molecular epidemiology of 14 Klebsiella pneumoniae carbapenemase (KPC) producers among 345 clinical isolates of Enterobacteriaceae with reduced susceptibility to carbapenems recovered from 11 separate hospitals in southern Brazil. The blaKPC-2 gene was detected in 14 isolates (4 %): six Enterobacter cloacae, five K. pneumoniae and three Serratia marcescens. Most of these isolates exhibited high-level resistance against β-lactams and ciprofloxacin, while the most active drugs were polymyxin B and amikacin. Genetic environment analysis, based on the classical Tn4401 structure, revealed six distinct platforms. Plasmids carrying blaKPC-2 were not typable and most were approximately 20 kb. Only KPC carbapenemases were found among the isolates studied, highlighting the local relevance of these enzymes in acquired resistance to carbapenems in Enterobacteriaceae. Our results contribute to the understanding of carbapenem resistance in Enterobacteriaceae and to the molecular characterization of KPC-2-producing isolates in Brazil.