Infections Caused by Pseudomonas maltophilia with Emphasis on Bacteremia: Case Reports and a Review of the Literature

Ten cases of Pseudomonas maltophilia bacteremia were identified over a five-year period at the University of Pittsburgh Medical Center. Our experience and a review of the literature show that P. maltophilia can cause a wide spectrum of disease. We present cases of pneumonia and infections of the biliary tract and urinary tract in which the organism was isolated simultaneously from blood. P. maltophilia endocarditis occurs in the context of iv drug abuse or as a postoperative complication of prosthetic valve surgery. Pseudobacteremia from contaminated equipment, disinfectants, and vascular catheters is the newest presentation for P. maltophilia infection. Hospitalization and prior antibiotic therapy are risk factors for serious P. maltophilia infection. Mortality due to P. maltophilia infection is low, despite the notable in vitro resistance of the organism to antibiotics. Trimethoprim-sulfamethoxazole, minocycline, doxycycline, and moxalactam are highly active in vitro against P. maltophilia. The triple combination of trimethoprim-sulfamethoxazole plus carbenicillin plus rifampin has been found to be synergistic in vitro and can be considered for serious infections.