Objective To evaluate the condition of Legionella contamination in some hospitals and hotels and provide a basis in a drstrict of Beijing for preventing and controlling Legionaires disease.
Methods Altogether 3 hospitals and 44 hotels were selected and water samples were taken from their cooling towers to examine for Legionella each month during July through September in 2007. The environment of the cooling towers and the maintenance procedures dealing with them were also investigated.
Results Legionella were detected in all the 3 hospitals and 26 hotels. The total percentage of meeting the standard among all the 47 units was 38.30%. Among the 265 samples collected, Legionella were detected in 76 samples, with a positive rate of 28.68%. In which 17 samples were collected from hospitals and 9 found positive, with the positive rate of 52.94%, another 248 samples were collected from hotels and 67 found positive, with the positive rate of 27.02%. Among the 76 positive samples 63 detected Legionella type LP1 and 7 detected type LP2-14, another 6 samples detected both LP1 and LP2-14. The environment of cooling towers was suitable for the growth of Legionella. The main maintenance procedure of cooling water was chemical processing and the composition of most chemicals were unknown.
Conclusion The contamination of cooling towers with Legionella is serious and the contamination in the hospitals is more severe than that in the hotels. The main type of Legionella is LP1. The maintenance procedures of the cooling towers need to be regulated.
DownLoad: