Stenotrophomonas maltophilia is an important pathogen in immunocompromised patients, such as patients with malignancies, long-term hospitalized patients, or patients receiving broad-spectrum antibiotic therapy. We confirmed an outbreak of S. maltophilia in allogenic bone marrow transplant patients in June 2007. To identify the source of the pathogens, environmental cultures were obtained from the transplantation unit. S. maltophilia strains were isolated from a bath chair, a shower head, and an automatic hot towel dispenser. Outbreak-related strains from 4 patients and 4 strains from the environment were compared by pulsed-field gel electrophoresis (PFGE). Two strains from blood cultures and one strain from the dispenser were identical, as confirmed by PFGE, which showed that the outbreak was associated with the automatic hot towel dispenser. Subsequently, many types of non-fermentative Gram-negative organisms were isolated from all automatic hot towel dispensers placed in other wards. These results indicate that medical equipment containing water requires careful attention to maintain sterility in use.
