Legionella in Dublin hospital water supplies.

An environmental survey was carried out which consisted of periodic and random sampling of water tanks and showers in two large Dublin hospitals. Of the samples 5.3% yielded Legionella bacteria. Legionella pneumophila of serogroups 3, 5 and 6 were isolated from these sites with viable counts ranging from 3.0 x 10(2) - 2.5 x 10(3) c.f.u./litre. The implementation of periodic sampling may, however, not be a worthwhile exercise unless an environmental site has been associated with cases of legionellosis. Emphasis should be placed on the prevention of contamination of environmental sites with legionellae and on the development and implementation of protocols and procedures for the isolation of legionellae to gain the necessary expertise should an epidemiological survey be required.