title: [Legionella and other bacteria in air humidifiers and cooling systems of air conditioning units--a survey].
abstract: Air humidifiers using cold water and cooling towers of air-conditioning systems provide the best settings for the growth of bacteria. Hence, we investigated 90 water samples for humidifiers and 15 water samples from cooling towers of hospitals, authorities, schools, and factories. The colony forming units/ml at 20 degrees C and 36 degrees C, the biological activity of added biocidal substances, and the occurrence of legionella were determined. About 90 percent of the samples showed no activity of the biocidal substance added, suggesting the uselessness of such substances. Furthermore, they exercised neither an influence on the CFU of the water samples nor on the occurrence of legionella. Legionella were isolated in 7 per cent of the humidifiers investigated, in 3 per cent of air conditioned buildings, respectively. 13 per cent of the cooling towers contained legionella. The risk of infection by air conditioning systems, humidifiers, cooling towers, and other emitters of infections agents should be controlled by the public health service.
authors.affiliation: Staatliches Medizinaluntersuchungsamt Braunschweig.
authors.forename: A
authors.initials: A
authors.lastname: Dermitzel
authors.forename: H H
authors.initials: HH
authors.lastname: Geuenich
authors.forename: H E
authors.initials: HE
authors.lastname: Müller
mesh_terms: D000389:Air Conditioning; D000391:Air Microbiology; D015169:Colony Count, Microbial; D006761:Hospitals; D006801:Humans; D006813:Humidity; D007875:Legionella / Q000302:isolation & purification*; D014871:Water Microbiology
vernacular_title: Legionellen und andere Bakterien in Umlaufsprühbefeuchtern und Rückkühlwerken von Klimaanlagen--eine Bestandsaufnahme.