Abstract: This work aims to establish a molecular detection method for the rapid detection of viable Legionella pneumophila based on 16S rRNA precursor,and the contamination level and status of L. pneumophila in the water environment of public places may be detected by this method and ISO method. The established method is based on the synthesis of 16S rRNA precursor in L. pneumophila via a nutritional stimulation,which is an indicator for cells’ viability. Pre-stimulated RT-qPCR method and ISO method were used to detect L. pneumophila and non-Legionella pneumophila,as well as other non-Legionella,and the specificity and sensitivity of these two methods were validated.Further,the pre-stimulated RT-qPCR method and ISO method were employed to detect L. pneumophila in the water environment of public places,and the consistency of the results between the 2 methods were compared.The 16S rRNA precursor of L. pneumophila increased slowly when the pre-stimulation time was > 3 h,thus the optimal pre-stimulation time was set to be 3 h. L. pneumophila were well detected by both pre-stimulated RT-qPCR method and ISO method,and the specificity for both was 100%. The Limit of Detection（LOD）by pre-stimulated RT-qPCR method was 10² cells/L,while LOD by ISO method was 10⁴ cells/L. The positive rate of L. pneumophila in the water environment of public places was 43.5%（30/69）by pre-stimulated RT-qPCR method and 40.6%（28/69）by ISO method,and the difference of detection by both methods was of no statistical significance（C²=0.119,P=0.730）. In conclusion,pre-stimulated RT-qPCR method is a rapid and effective method for detecting L. pneumophila with high sensitivity and specificity,and it can be used as a potential alternative to the ISO method.

Key words: Legionella pneumophila, PCR, water environment, public place, 16S rRNA, rapid detection method.