Nosocomial infections with ceftazidime-resistant Pseudomonas aeruginosa: risk factors and outcome.

Prospective studies were conducted for nosocomial Pseudomonas aeruginosa infections from February 1, 1994, to October 30, 1995. Of 97 P. aeruginosa isolates from 97 patients, 35 were resistant to ceftazidime. Logistic regression revealed previous cephalosporin or piperacillin use as independent risk factors for nosocomial ceftazidime-resistant P. aeruginosa infection. Pulsed-field gel electrophoresis revealed that four nosocomial ceftazidime-resistant P. aeruginosa infections were caused by cross-infection, probably through medical personnel.