title: Are there effective interventions to prevent hospital-acquired Legionnaires' disease or to reduce environmental reservoirs of Legionella in hospitals? A systematic review.
abstract: 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.
authors.affiliation: Laboratory of Microbiology and Molecular Biology, Centro Hospitalar de Lisboa Ocidental, Lisbon, Portugal. Electronic address: dejaniradealmeida@gmail.com.
authors.forename: Dejanira
authors.initials: D
authors.lastname: Almeida
authors.affiliation: Laboratory of Microbiology and Molecular Biology, Centro Hospitalar de Lisboa Ocidental, Lisbon, Portugal.
authors.forename: Elisabete
authors.initials: E
authors.lastname: Cristovam
authors.affiliation: Laboratory of Clinical Pharmacology and Therapeutics, Faculty of Medicine, Universidade de Lisboa, Lisbon, Portugal; Clinical Pharmacology Unit, Instituto de Medicina Molecular, Lisbon, Portugal.
authors.forename: Daniel
authors.initials: D
authors.lastname: Caldeira
authors.affiliation: Laboratory of Clinical Pharmacology and Therapeutics, Faculty of Medicine, Universidade de Lisboa, Lisbon, Portugal; Clinical Pharmacology Unit, Instituto de Medicina Molecular, Lisbon, Portugal.
authors.forename: Joaquim J
authors.initials: JJ
authors.lastname: Ferreira
authors.affiliation: Laboratory of Microbiology and Molecular Biology, Centro Hospitalar de Lisboa Ocidental, Lisbon, Portugal.
authors.forename: Teresa
authors.initials: T
authors.lastname: Marques
mesh_terms: D003300:Copper / Q000494:pharmacology; D003428:Cross Infection / Q000453:epidemiology* / Q000517:prevention & control*; D004202:Disinfectants / Q000494:pharmacology; D004783:Environmental Microbiology; D006761:Hospitals; D006801:Humans; D017053:Infection Control / Q000379:methods*; D007875:Legionella / Q000187:drug effects / Q000254:growth & development; D007877:Legionnaires' Disease / Q000453:epidemiology* / Q000517:prevention & control*; D012834:Silver / Q000494:pharmacology
chemical_list: D004202:Disinfectants; D012834:Silver; D003300:Copper
keywords: Cross-infection; Disinfection; Legionellosis; Prevention and control; Treatment outcome