Serum levels of antibodies against Legionella pneumophila among workers in public places with centralized air conditioning system in southern area of China

ObjectiveTo investigate Legionella pneumophila(Lp)infection status among workers in public places with centralized air conditioning system in southern area of China.MethodsFrom 2008 to 2009,a total of 427 workers in 7 public places with centralized air-conditioning system and the cooling tower water of the system was contaminated by Lp and 435 workers from 14 public places without centralized air-conditioning system were selected.Questionnaire survey and detection of serum Lp1-Lp7 IgG were conducted among the participants.ResultsThe workers in the public places with centralized air-conditioning system had higher IgG levels(median:10.66 U/ml,95% confidence interval 95%CI6.36-17.95 U/ml)than the workers from the public places without centralized air-conditioning system(median:9.50 U/ml,95%CI:4.98-16.35 U/ml),with a significant difference(P<0.05).The multiple stepwise regression analysis showed that after adjustment for gender,age,smoking,alcohol drinking,and history of chronic diseases,whether using the centralized air-conditioning system in workplaces was an influencing factor of Lp infection(b'=0.075,P<0.05).ConclusionThe cooling tower water pollution of the centralized air-conditioning system is one of risk factors for Lp infection among workers in public places.