Legiolert for detection and storage of various Legionella pneumophila subspecies

Presentation by Sébastien P. Faucher PhD of McGill University

Legiolert is a promising technology to detect Legionella pneumophila in water system. This system provides most probable numbers based on liquid culturing and enzymatic detection. Previous studies have shown good agreement between Legiolert and standard culture technique; however, it is unknown if the system can detect diverse sequence-based types (ST) and subspecies. By isolating and typing colonies directly from the Legiolert medium, we confirmed that this technique can detect a variety of STs, including ST1, ST378, ST1427, ST2859, ST3054, and ST3069, and all currently known L. pneumophila subspecies (Pneumophila, Fraseri, Pascuelli and Raphaeli). Further, we developed a procedure to easily preserve Legiolert culture by simply adding glycerol to a final concentration of 10% and storing at or less than -20°C. This could facilitate retrospective analysis of L. pneumophila positive samples for epidemiological investigation of outbreaks. In conclusion, Legiolert seems well suited for routine surveillance of L. pneumophila in water systems.