A study of Legionella pneumophilia in Tianjin, China

Legionella is a bacterium identified as the causative agent of Legionnaires' disease commonly found in water and soil in natural environments and human habitats. While most studies are focused on cooling tower water as the source of infection, few studies have compared Legionella from cooling-tower water and water in man-made environments. This cross-sectional study with a randomized cluster sampling design aims to provide information on Legionella found in cooling-tower water and water in man-made environments. Legionella was identified using a dual analytical approach: the serological and the 16SrRNA semi-nest PCR methods. Nine different types of Legionella were identified with the Lp7 type detected in China for the first time. Results indicated slight but insignificantly increased odds (OR = 1.64, 95%CI = 0.54-4.98) of Legionella detection in cooling tower water as compared to water obtained from fountains and parks, suggesting that the mechanism of exposure plays an important role in the causal pathway of outbreaks of Legionnaires' disease.