Experiences of the First 16 Hospitals Using Copper-Silver Ionization for Legionella Control:  Implications for the Evaluation of Other Disinfection Modalities

Janet E. Stout, PhD; Victor L. Yu, MD

Vol. 24 No. 8 Infection Control and Hospital Epidemiology

Stated in the ABSTRACT on the first page:

BACKGROUND AND OBJECTIVESHospital-acquired legionnaires’ disease can be prevented by disinfection of hospital water systems. This study assessed the long-term efficacy of copper–silver ionization as a disinfection method in controlling Legionella in hospital water systems and reducing the incidence of hospital-acquired legionnaires’ disease. A standardized, evidence-based approach to assist hospitals with decision making concerning the possible purchase of a disinfection system is presented.”

RESULTSAll 16 hospitals reported cases of hospital-acquired legionnaires’ disease prior to installing the copper–silver ionization system.”  “No cases of hospital-acquired legionnaires’ disease have occurred in any hospital since 1995.”

CONCLUSIONS: “This study represents the final step in a proposed 4-step evaluation process of disinfection systems that includes (1) demonstrated efficacy of Legionella eradication in vitro using laboratory assays, (2) anecdotal experiences in preventing legionnaires’ disease in individual hospitals, (3) controlled studies in individual hospitals, and (4) validation in confirmatory reports from multiple hospitals during a prolonged time (5 to 11 years in this study). Copper–silver ionization is now the only disinfection modality to have fulfilled all four evaluation criteria(Infect Control Hosp Epidemiol 2003;24:563-568).”

Stated on page 5 the last two paragraphs in the 2nd column:

“Advantages of copper–silver ionization are that it is more cost-effective than hyperchlorination, is easier to maintain, and does not corrode piping or plumbing fixtures, and in the event of mechanical failure, recontamination is delayed for weeks, allowing a safety buffer.33-35  In contrast, if a chlorinator fails, recontamination occurs rapidly.’

“The four evaluation criteria listed earlier have now been fulfilled for copper–silver ionization. We recommend that this process of evaluation be applied to other newer disinfection approaches such as those involving chlorine dioxide and monochloramine. It may be several years before sufficient controlled trials of these modalities are available for scientific scrutiny. This study documents the long-term efficacy of copper–silver ionization in reducing Legionella in hospital hot water distribution systems, as well as reducing or eliminating cases of hospital-acquired legionnaires’ disease.”

Download Full Study:  Experiences of the First 16 Hospitals