Identification of an imipenem-resistant Pseudomonas aeruginosa clone among patients in a hospital in Rio de Janeiro

A total of 85 Pseudomonas aeruginosa isolates were obtained from October 1999 to April 2000 in a tertiary care hospital in Rio de Janeiro, Brazil. The imipenem susceptibility was evaluated by disk diffusion and agar dilution methods, and the clonal relationship among 67 isolates was examined by macrorestriction profile analysis following pulsed-field gel electrophoresis. Imipenem resistance was observed in 52 (61.2%) isolates. Imipenem-resistant P. aeruginosa isolates were separated into 10 genotypes, 73% of which belonged to genotype A. Identification of a single P. aeruginosa clone with a high rate of imipenem resistance emphasizes the need to control the transmission of this organism among patients.