Prolonged effect of two combined methods for Legionella disinfection in a hospital water system.
This study was conducted in our 650 bed general hospital, which is situated on the southern outskirts of Milan (Italy). After a first nosocomial case of pneumonia (caused by Legionella pneumophila serogroup 1), we first used a conventional method (heat shock) without success. To solve the problem we then tried a copper-silver ionization system combined with a chlorine dioxide device. During the four years after the installation of these two systems we recorded a significant (p < or = 0.05) reduction in Legionella colonization, and no new cases of Legionnaires' disease were observed. Our results suggest that the Cu-Ag ionization system, combined with a chlorine dioxide device, is a highly promising method for the control of Legionella pneumophila in a hospital water distribution system.
Casari
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Microbiology Unit, Clinical Laboratories, IRCCS Istituto Clinico Humanitas, Rozzano, Milan, Italy. erminia.casari@humanitas.it
Ferrario
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Montanelli
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D017606:Chlorine Compounds / Q000494:pharmacology; D003300:Copper / Q000494:pharmacology; D003428:Cross Infection / Q000517:prevention & control*; D004203:Disinfection / Q000379:methods*; D006361:Heating; D006769:Hospitals, General; D006801:Humans; D017053:Infection Control / Q000379:methods; D007558:Italy; D016952:Legionella pneumophila / Q000187:drug effects / Q000254:growth & development*; D007877:Legionnaires' Disease / Q000517:prevention & control*; D010087:Oxides / Q000494:pharmacology; D012834:Silver / Q000494:pharmacology; D014871:Water Microbiology; D014881:Water Supply
D017606:Chlorine Compounds; D010087:Oxides; D012834:Silver; D003300:Copper; C025109:chlorine dioxide