Backgroud： The prevention of Legionella spp. colonization of water distribution systems is a critical issue in healthcare settings and only an effective disinfection of water systems and appropriate environmental sur...Backgroud： The prevention of Legionella spp. colonization of water distribution systems is a critical issue in healthcare settings and only an effective disinfection of water systems and appropriate environmental surveillance strategies allow to prevent nosocomial legionellosis. Methods： Due to the temporary effectiveness （increase of the temperature of water in boilers and shock hyperchlorination）, the high costs （point-of-use water filters） or the ineffectiveness （hydrogen peroxide, H202） of the previous control procedures, 3 devices （one for each hot water loop） continuously injecting monochloramine have been installed in two different Italian hospitals heavily contaminated by Legionellapneumophila SG3 and SG6. Aim： To evaluate the efficacy of continuous disinfection by monochloramine for control of Legionella on domestic hot water （DHW） distribution system of health-care facilities. Findings： One month after the disinfection of DHW with monochloramine, the load ofL. pneumophila SG3 and SG6 （previous mean count ranging from 103 to 105 CFU/L）, as well as the Heterotrophic Plate Count （HPC） （previous mean count ranging from 〉 10^2 to 〉 10^4 CFU/mL）, decreased at undetectable levels in 100% of the sampling points in the two hospitals. Conclusion： The results suggest that continuous injection of monochloramine on DHW systems can fully control L. pneumophila and HPC in contaminated hospitals since the beginning of its application.展开更多
文摘Backgroud： The prevention of Legionella spp. colonization of water distribution systems is a critical issue in healthcare settings and only an effective disinfection of water systems and appropriate environmental surveillance strategies allow to prevent nosocomial legionellosis. Methods： Due to the temporary effectiveness （increase of the temperature of water in boilers and shock hyperchlorination）, the high costs （point-of-use water filters） or the ineffectiveness （hydrogen peroxide, H202） of the previous control procedures, 3 devices （one for each hot water loop） continuously injecting monochloramine have been installed in two different Italian hospitals heavily contaminated by Legionellapneumophila SG3 and SG6. Aim： To evaluate the efficacy of continuous disinfection by monochloramine for control of Legionella on domestic hot water （DHW） distribution system of health-care facilities. Findings： One month after the disinfection of DHW with monochloramine, the load ofL. pneumophila SG3 and SG6 （previous mean count ranging from 103 to 105 CFU/L）, as well as the Heterotrophic Plate Count （HPC） （previous mean count ranging from 〉 10^2 to 〉 10^4 CFU/mL）, decreased at undetectable levels in 100% of the sampling points in the two hospitals. Conclusion： The results suggest that continuous injection of monochloramine on DHW systems can fully control L. pneumophila and HPC in contaminated hospitals since the beginning of its application.
