Surveillance of carbapenem-resistant Pseudomonas aeruginosa isolates from Puerto Rican Medical Center Hospitals: dissemination of KPC and IMP-18 beta-lactamases.

During a 6-month period, 37/513 (7.2%) Pseudomonas aeruginosa isolates belonging to 13 pulsed-field gel electrophoresis (PFGE) groups from Puerto Rican hospitals were carbapenem nonsusceptible. Seven of 37 isolates from four PFGE groups carried bla(IMP-18), and 25/37 isolates from seven PFGE groups carried bla(KPC). The results indicated the clonal spread of bla(KPC)-positive P. aeruginosa isolates into several Puerto Rican hospitals and the dissemination of bla(IMP-18) and bla(KPC) into genetically unrelated isolates.