DETECTION OF LEGIONELLA PNEUMOPHILA IN ENVIRONMENTAL AEROSOLS OF COOLING TOWERS BY IMPACT SAMPLING METHODS

摘要

To evaluate the efficiency of classic air sampling methods in case of suspicious bioaerosols of Legionella, we tested 3 biocollectors in outdoor conditions : a six-stage microbial air sampler (S6, Andersen sampler), a single-stage multiple-hole impactor (ATΩ) and a liquid impinger sampler (AGI 30). The 3 biocollectors were used simultaneously in 7 assays on-site near cooling towers. The selected sites were located in Paris city and the samples were obtained close to the installations in aerosols discharged from the towers. Each of the 3 sampling methods allowed the detection of airborne Legionella pneumophila (2 to 4 CFU /m~3) but was not related to the concentration of bacteria in water. The background flora present in the water of cooling towers could inhibit the growth of Legionella on culture media. The results showed that the impact sampling methods are useful in heterogeneous and variable conditions.