title: Prevalence and distribution of Legionella spp in potable water systems in Germany, risk factors associated with contamination, and effectiveness of thermal disinfection.
abstract: BACKGROUND
  Worldwide, Legionella spp are a common cause of community-acquired pneumonia. Potable water systems are a main reservoir; however, exposure in the community is unknown.
  
  
  METHODS
  Water samples from 718 buildings in Germany were collected. Possible risk factors were prospectively recorded. All samples were tested for Legionella spp using cultural microbiologic methods. Samples were assigned to 1 of 5 levels of contamination. Statistical analysis was performed to determine the influence of risk factors for contamination and, in a subgroup of buildings, for unsuccessful thermal disinfection.
  
  
  RESULTS
  In total, 4,482 water samples from 718 different water supply systems were analyzed. In 233 buildings (32.7%), Legionella spp were identified, 148 (63.5%) of which had a medium or higher level of contamination. The most common species was Legionella pneumophila (94%). Contamination was strongly associated with temperature in the circulation, but not with the size of the building, time of the year, or transport time to the laboratory. Thermal disinfection was successful in fewer than half of the buildings.
  
  
  CONCLUSIONS
  There is relevant exposure to Legionella spp in the community. Water systems are not always up to current technical standards. Although microbiological risk assessment remains a challenge, there is a case for monitoring for Legionella spp outside of hospitals.
authors.affiliation: Wisplinghoff Laboratories, Cologne, Germany. Electronic address: e.kruse@wisplinghoff.de.
authors.forename: Eva-Brigitta
authors.initials: EB
authors.lastname: Kruse
authors.affiliation: HCT HygieneConsult GmbH, Cologne, Germany.
authors.forename: Arno
authors.initials: A
authors.lastname: Wehner
authors.affiliation: Wisplinghoff Laboratories, Cologne, Germany; Institute for Medical Microbiology, Immunology, and Hygiene, University of Cologne, Cologne, Germany.
authors.forename: Hilmar
authors.initials: H
authors.lastname: Wisplinghoff
mesh_terms: D058491:Bacterial Load; D004203:Disinfection / Q000379:methods*; D060766:Drinking Water / Q000382:microbiology*; D005858:Germany; D006358:Hot Temperature; D007875:Legionella / Q000145:classification / Q000302:isolation & purification*; D015995:Prevalence; D011446:Prospective Studies; D012307:Risk Factors
chemical_list: D060766:Drinking Water
keywords: Microbiological monitoring; Technical assessment; Water-related infection risks