Outbreak of Stenotrophomonas maltophilia bacteremia in allogenic bone marrow transplant patients: Role of severe neutropenia and mucositis

From March 1997 through November 1997, 8 allogenic bone marrow transplant ( BMT) patients developed Stenotrophomonas maltophilia bacteremia on the hema tology service at UCLA Medical Center (Los Angeles), Five of these patients had undergone transplantation during the same hospitalization that S. malt ophilia bacteremia was detected (case patients), Compared with 7 concurrent ly hospitalized allogenic BMT patients (control patients), the 5 case patie nts were more likely to have been hospitalized in room A (P = .045), to hav e severe neutropenia on the culture date (P = .028), to have a longer durat ion of severe neutropenia (P = .05), to have severe mucositis (P = .028), a nd to have received total parenteral nutrition (P = .028), Pulsed-held gel electrophoresis revealed that 2 of 3 isolates from case patients hospitaliz ed in room A were identical. In allogenic BMT patients, severe neutropenia and severe mucositis may promote infection with S. maltophilia by impairing host defenses.