Legionella spp in cooling tower water and air samples were detected by using PCR and reverse dot blot analysis The sequences used for PCR amplification included 5S rDNA

16S rDNA and mip gene Seminested PCR method was used for 16S rRNA gene sequence amplification Eleven cooling tower water samples were analysed

and 100% of the samples was Legionella positive and 45% contained L pneumophila In the experiments of artificial aerosolization of Legionella cells

airborne Legionella cells were successfully collected and detected Two air samples collected respectively from sites above two cooling towers were Legionella positive These results indicated that the 5S rRNA gene PCR and probe hybridization method (Perkin Elmer EnviroAmp Legionella Kits) and 16S rRNA gene seminested PCR method can used to detect Legionella spp in water samples as well as in air samples