title: Controlled evaluation of copper-silver ionization in eradicating Legionella pneumophila from a hospital water distribution system.
abstract: A controlled evaluation was made of the efficacy of copper-silver ionization in eradicating Legionella pneumophila from a hospital water supply. Copper-silver ionization units were installed on the hot water recirculation line of one building with water fixtures positive for Legionella species. Another building with the same water supply served as a control. Legionella species persisted within the system when copper and silver concentrations were < 0.3 and < 0.03 ppm, respectively. When copper and silver concentrations were > 0.4 and > 0.04 ppm, respectively, there was a significant decrease in Legionella species colonization, but the percentage of water fixtures positive for organisms was unchanged in the control building. When the ionization unit was inactivated, water fixtures continued to be free of Legionella species for 2 additional months. Copper-silver ionization can eradicate L. pneumophila in a water distribution system. The advantages of copper-silver ionization include relatively low cost, straightforward installation, easy maintenance, nontoxic by-products and the presence of a disinfecting residual.
authors.affiliation: Department of Medicine, University of Pittsburgh, Pennsylvania.
authors.forename: Z
authors.initials: Z
authors.lastname: Liu
authors.forename: J E
authors.initials: JE
authors.lastname: Stout
authors.forename: L
authors.initials: L
authors.lastname: Tedesco
authors.forename: M
authors.initials: M
authors.lastname: Boldin
authors.forename: C
authors.initials: C
authors.lastname: Hwang
authors.forename: W F
authors.initials: WF
authors.lastname: Diven
authors.forename: V L
authors.initials: VL
authors.lastname: Yu
mesh_terms: D003300:Copper; D004203:Disinfection / Q000379:methods*; D005069:Evaluation Studies as Topic; D006787:Hospitals, Veterans; D006801:Humans; D016952:Legionella pneumophila / Q000254:growth & development*; D010414:Pennsylvania; D012834:Silver; D014871:Water Microbiology; D014881:Water Supply
chemical_list: D012834:Silver; D003300:Copper