title: Viable Legionella pneumophila bacteria in natural soil and rainwater puddles.
abstract: OBJECTIVE
  For the majority of sporadic Legionnaires' disease cases the source of infection remains unknown. Infection may possible result from exposure to Legionella bacteria in sources that are not yet considered in outbreak investigations. Therefore, potential sources of pathogenic Legionella bacteria--natural soil and rainwater puddles on roads--were studied in 2012.
  
  
  RESULTS
  Legionella bacteria were detected in 30% (6/20) of soils and 3·9% (3/77) of rainwater puddles by amoebal coculture. Legionella pneumophila was isolated from two out of six Legionella positive soil samples and two out of three Legionella positive rainwater samples. Several other species were found including the pathogenic Leg. gormanii and Leg. longbeachae. Sequence types (ST) could be assigned to two Leg. pneumophila strains isolated from soil, ST710 and ST477, and one strain isolated from rainwater, ST1064. These sequence types were previously associated with Legionnaires' disease patients.
  
  
  CONCLUSIONS
  Rainwater and soil may be alternative sources for Legionella.
  
  
  CONCLUSIONS
  The detection of clinically relevant strains indicates that rainwater and soil are potential sources of Legionella bacteria and future research should assess the public health implication of the presence of Leg. pneumophila in rainwater puddles and natural soil.
authors.affiliation: National Institute for Public Health and the Environment, Bilthoven, the Netherlands.
authors.forename: E
authors.initials: E
authors.lastname: van Heijnsbergen
authors.forename: A M
authors.initials: AM
authors.lastname: de Roda Husman
authors.forename: W J
authors.initials: WJ
authors.lastname: Lodder
authors.forename: M
authors.initials: M
authors.lastname: Bouwknegt
authors.forename: A E
authors.initials: AE
authors.lastname: Docters van Leeuwen
authors.forename: J P
authors.initials: JP
authors.lastname: Bruin
authors.forename: S M
authors.initials: SM
authors.lastname: Euser
authors.forename: J W
authors.initials: JW
authors.lastname: den Boer
authors.forename: J A C
authors.initials: JA
authors.lastname: Schalk
mesh_terms: D016952:Legionella pneumophila / Q000145:classification / Q000235:genetics / Q000302:isolation & purification*; D050296:Microbial Viability; D011891:Rain; D012988:Soil Microbiology; D014871:Water Microbiology
keywords: Legionella; Legionella pneumophila; amoebal coculture; natural soil; rainwater; source investigation