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Chapter 113 : Controlling Legionella in Hospital Water Systems: Facts versus Folklore
Acute-care and long term-care facilities continue to experience cases of hospital-acquired Legionnaires’ disease. One of the major unresolved issues is whether the recommendations found in the guidelines will, if followed, result in the control and prevention of hospital-acquired Legionnaires’ disease. An evidence-based approach has been suggested as a way to resolve many of these issues. If applied to a guideline, the criteria should be that (i) the recommendations should be prospectively validated under controlled studies using a step-wise approach, (ii) the evaluation should be a prolonged observational period (>1 year) to evaluate the efficacy of the recommendations, and (iii) the recommended approach/actions should achieve the expected result-prevention of the disease through environmental control. Legionnaires’ disease is an environmentally acquired illness. One recommendation often found in guidance documents is “remove showerheads and aerators monthly for cleaning with chlorine bleach’’. The role of environmental monitoring in Legionella prevention has been a source of debate for many years. A number of disinfection methods have been used for control of Legionella in hospital water systems. These include thermal eradication (heat and flush), hyperchlorination, copper-silver ionization, point-of-use filters, and chlorine dioxide. Each of these methods has completed some of the evaluation criteria. All four steps of the evaluation criteria have been fulfilled for copper-silver ionization. The path to effective control of hospital acquired Legionnaires’ disease must be evidence based. Patients and healthcare facilities suffer when unconfirmed and untested recommendations become part of prevention guidelines.