Legionnaires' disease: Further evidence to implicate water storage and distribution systems as sources

Abstract

The nine-storey hotel was built about 14 years ago and has 48 bedrooms; it is not air-conditioned but has an extract ventilation system for the dining room, kitchens, and bathrooms. During the summer of 1979 small volume water samples of up to a litre were taken from taps, and other sites in the hotel but L. pneumophila was not isolated. Further water samples were collected in October. Serological studies in December on guinea-pigs inoculated with shower water suggested the presence of legionellae. When more samples were taken early in 1980 the organism was isolated from samples of water (ranging from 2 to 25 litres) from two storage tanks, hot and cold water taps, and shower outlets but not from the mains water supply or from tap water in five other buildings nearby. In view of these findings and the association with confirmed cases of Legionnaire's disease, the hotel was closed temporarily for cleaning and chlorination (with 50 parts per million of free chlorine) of its tanks and water distribution system. Subsequently a continuous chlorination unit was installed and is now in operation. Gas-liquid chromatography studies have since confirmed the identification of L. pneumophila.