Prevention of Legionella Infections in a Bone Marrow Transplant Unit: Multifaceted Approach to Decontamination of a Water System

Abstract

To evaluate measures intended to reduce Legionella infections in patients undergoing bone marrow transplantation (BMT). Ongoing clinical and microbiological surveillance for Legionella colonization or infection was undertaken. All neutropenic patients with pulmonary infiltrates and fever unresponsive to broad-spectrum antibiotics were tested for Legionella organisms. A 505-bed medical-surgical hospital with a designated BMT unit. Two hundred twenty-five patients underwent BMT; 201 were treated on a new BMT unit. The incidence of Legionella infections was compared to that seen in an estimated 150 neutropenic patients treated on other units. A combined approach to decontamination of a hospital water supply was assessed. This included heating, particulate filtration, ultraviolet sterilization, and monthly pulse hyperchlorination of water supplied to the BMT unit. The incidence of Legionella infections was assessed on the BMT unit and compared with the frequency elsewhere in the hospital. There were only three cases of Legionella pneumonia among 201 patients undergoing transplantation on a new BMT unit. In contrast, 33 cases of Legionella infections were detected from approximately 150 patients treated on general medical floors. A multifaceted approach to decontamination of a hospital water system led to a marked reduction in Legionella infections.