Are there effective interventions to prevent hospital-acquired Legionnaires' disease or to reduce environmental reservoirs of Legionella in hospitals? A systematic review

Published:August 11, 2016DOI:


      • The optimal method to prevent hospital-acquired LD is not well established.
      • There are no data regarding the efficacy of interventions in the reduction of the incidence of hospital-acquired LD.
      • Copper-silver ionization and Ultraviolet light decreased the risk of Legionella positivity in environmental samples.


      Legionnaires' disease (LD) is recognized as an important hospital-acquired disease. Despite the several methods available, the optimal method to control hospital-acquired LD is not well established and their overall efficacy requires further evaluation.


      To systematically review all controlled trials evaluating the efficacy of interventions to prevent hospital-acquired LD in patients at high risk of developing the disease and its effects on environmental colonization.


      A database search was performed through PubMed and the Cochrane Central Register of Controlled Trials (inception-November 2014). Eligible studies included all controlled studies evaluating interventions to prevent hospital-acquired LD in patients at high risk or evaluating the effect on environmental colonization. Both individual and pooled risk estimates were reported using risk ratio (RR) and 95% confidence intervals (95% CIs).


      There were no studies evaluating the risk reduction in hospital-acquired LD, but 4 studies evaluated the influence of copper-silver ionization and ultraviolet light in the reduction of environmental reservoirs of Legionella. The meta-analysis showed a significant 95% risk reduction of Legionella positivity in environmental samples using copper-silver ionization (RR, 0.05; 95% CI, 0.01-0.17) and 97% risk reduction with ultraviolet light (RR, 0.03; 95% CI, 0.002-0.41).


      The best available evidence suggests that copper-silver ionization and ultraviolet light are effective in reducing Legionella positivity in environmental samples. Nevertheless, the low quality of evidence weakens the robustness of conclusions.

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