Control of Legionella contamination in a hospital water distribution system by monochloramine

Background: We report the results of 1-year application of monochloramine to control Legionella pneumophila contamination in a hospital hot water distribution system. Methods: In the main building of the hospital, a device continuously distributing monochloramine was installed. Legionella pneumophila and Pseudomonas spp contamination was followed in comparison with 2 other water networks in the same building using chlorine dioxide. Results: Monochloramine significantly reduced the number of contaminated sites compared with baseline (from 97.0% to 13.3%, respectively), chlorine dioxide device I ( from 100% to 56.7%, respectively), and device II (from 100% to 60.8%, respectively). No positive sample exceeded 104 colony-forming units/L versus 59.4% at baseline. Conclusion: Monochloramine could represent a good alternative to chlorine dioxide in controlling legionellae contamination in public and private buildings. Copyright (C) 2012 by the Association for Professionals in Infection Control and Epidemiology, Inc. Published by Elsevier Inc. All rights reserved.