Bacteremia due to Stenotrophomonas (Xanthomonas) maltophilia: a prospective, multicenter study of 91 episodes.

We identified 91 cases of bacteremia due to Stenotrophomonas (Xanthomonas) maltophilia in a prospective, multicenter observational study. The patients were highly compromised; the majority had an underlying malignancy, had received immunosuppressive therapy, and had indwelling venous catheters. Although 94% of patients received an antimicrobial agent to which the blood isolate was susceptible, the mortality among these patients 14 days after the onset of bacteremia was 21%. Mortality was significantly correlated with the presence of a hematologic malignancy or neutropenia or transplantation, immunosuppressive therapy, and a severity-of-illness score of > 4. S. maltophilia infection is associated with substantial morbidity and mortality among highly compromised patients. The organism is typically resistant to expanded spectrum beta-lactam agents and aminoglycoside antibiotics. Trimethoprim-sulfamethoxazole should be administered if the isolate is susceptible to this combination; addition of another agent to which the isolate is susceptible should be considered in treating patients who are neutropenic, immunocompromised, or critically ill.