[Occurrence and the susceptibility to antimicrobial agents in Pseudomonas aeruginosa and Acinetobacter sp. at a tertiary hospital in southern Brazil].

INTRODUCTION The main mechanism of emerging resistance in Pseudomonas aeruginosa and Acinetobacter sp. isolates is the production of metallo-β-lactamases (MβLs). MβLs are enzymes capable of hydrolyzing cephalosporins, penicillins and carbapenems, but not monobactams (aztreonam), which are often used as antimicrobial therapy to treat nosocomial infections. METHODS An observational descriptive and retrospective study was designed to assess the frequency of MβLs among strains of P. aeruginosa and Acinetobacter sp. obtained from a tertiary hospital in southern Brazil. RESULTS MβL production was observed in 77.6% (n = 173/223) for P. aeruginosa isolates and 22.4% (n = 50/223) of Acinetobacter sp. isolates. The Acinetobacter sp. isolates showed 92.8% sensitivity to amikacin and P. aeruginosa isolates showed 58.9% sensitivity to aztreonam. CONCLUSIONS The MβL indices determined confirm the global concern with this mechanism of resistance.