Carbapenem-resistant Acinetobacter spp. and Pseudomonas aeruginosa at the University Hospital of Santa Maria, Rio Grande do Sul state, Brazil

Abstract

AIMS: To evaluate the characteristics of antimicrobial susceptibility of carbapenem-resistant Acinetobacter spp. and Pseudomonas aeruginosa isolated from August 2011 to January 2012 from inpatients at the University Hospital of Santa Maria, Santa Maria, Rio Grande do Sul, Brazil. METHODS: A retrospective study was conducted by consulting the database of the Microbiology Laboratory, which included all isolates of Acinetobacter spp. and P. aeruginosa from different clinical specimens collected from hospitalized patients who had resistant or intermediate profile to carbapenemic antimicrobials used in this hospital (imipenem, meropenem and ertapenem) verified through conventional methodology by disc diffusion (Kirby-Bauer) or automated method (MicroScan ® - Siemens) according to the standards recommended by the Clinical and Laboratory Standards Institute. RESULTS: In the studied period 58 samples of nonfermenters Gram-negative bacilli resistant to carbapenems were found, 32 of the genus Acinetobacter and 26 of P. aeruginosa. Acinetobacter spp. was more isolated in the intensive care unit, while P. aeruginosa prevailed in the emergency and outpatient departments. Both microorganisms came mainly from respiratory secretions. CONCLUSIONS: In this study, Acinetobacter spp. and P. aeruginosa showed high antimicrobial resistance. Polymyxin B was a good antimicrobial for the treatment of infections caused by microorganisms resistant to carbapenems in this hospital.