Peer-Reviewed Research Study

Controlling Legionella in Hospital Water Systems: Experience With the Superheat-and-Flush Method and Copper-Silver Ionization

Janet E. Stout, Yu-Sen E. Lin, Angella M. Goetz, Robert R. Muder
Cambridge University Press, Infection Control and Hospital Epidemiology, December 1998

This study evaluated the efficacy of superheat-and-flush and copper-silver ionization for Legionella control in an acute care hospital. The hospital had been using the superheat-and-flush method for 13 years but was still experiencing incidences of Legionnaires’ disease.

Legionnaires’ cases decreased once the copper-silver ionization system was installed, with no cases reported in the last year evaluated by the study (1997). The average number of Legionnaires’ cases from 1979 to 1996 are included below.

  • 1979-1981 (no disinfection method): 25 cases per year
  • 1982-1994 (superheat-and-flush method): 6 cases per year
  • 1995-1997 (copper-silver ionization method): 2 cases per year

Copper-silver ionization was found to be more effective in controlling Legionella than superheat-and-flush. The study notes that hospitals must conduct routine Legionella testing and closely monitor ion concentrations for copper-silver ionization to remain effective.

Related studies

Examining the Efficacy of Copper-Silver Ionization for Management of Legionella

Hospitalizations Due to Selected Infections Caused by Opportunistic Premise Plumbing Pathogens and Reported Drug Resistance in the United States Older Adult Population

Controlling Legionella in Hospital Drinking Water: An Evidence-Based Review of Disinfection Methods

Highlighted author

Dr. Janet E. Stout

Dr. Janet E. Stout is the president and director of the Special Pathogens Laboratory, and a research associate professor at the University of Pittsburgh. A clinical and environmental microbiologist, Dr. Stout is internationally recognized for more than 30 years of research in Legionella and is credited as the first to demonstrate the link between Legionnaires' disease and the presence of Legionella in hospital water systems. Dr. Stout was instrumental in developing the first US prevention strategy for hospital-acquired Legionnaires' disease that now serves as the model for national Legionella guidelines. She serves on the Legionella standards committees for the America Society of Heating, Refrigerating and Air-Conditioning Engineers' (ASHRAE) Standards 12 and the proposed Legionella standard.

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