Legionella species, serogroups and subgroups found in the environment in Singapore.

Over a period of seven months, 87 samples of water collected from 48 air-conditioning cooling-towers on 15 sites in Singapore yielded 19 strains of Legionella. Legionellas were found in 7 of the 15 sites. The strains isolated fell into 7 species, serogroups or subgroups of the genus Legionella. Only 11% of them belonged to the more pathogenic Pontiac subgroup of Legionella pneumophila serogroup 1.