Detection of an international multiresistant clone belonging to sequence type 654 involved in the dissemination of KPC-producing Pseudomonas aeruginosa in Argentina

Abstract

The emergence of Klebsiella pneumoniae carbapenemase (KPC) has now become a global concern. KPC producers are mostly Enterobacteriaceae, but Pseudomonas aeruginosa have also been reported and mostly identified in the American continent.1–4 However, it is unknown if this is due to the spread of epidemic strains, since the multilocus sequence type (ST) has not been provided in most of those reports. The aim of this work was to characterize KPC-producing P. aeruginosa isolated in Argentina from 2006 to June 2011. Since 2005, we designed an algorithm to detect carbapenemases (metallo-β-lactamases, KPC, etc.) in P. aeruginosa at the level of the clinical microbiology laboratory, which was implemented among 432 hospitals. All P. aeruginosa were screened through that algorithm, and KPC production was suspected in isolates with high-level resistance to carbapenems and aztreonam (absence of disc zones) and a negative synergy test result between the carbapenems and EDTA, a phenotype consistent with the reported patterns of KPC-producing P. aeruginosa.