[Prevalence of glucosyl transferase Lgt among Legionella pneumophila strains isolated from various sources].

Aim: Determine various members of Lgt glucosyl transferase family among microorganisms of Legionellaceae genus from museum collection and legionellae strains recently isolated in the Russian Federation and Germany.
Materials and Methods: Presence of 3 types of glucosyl transferase were determined in 73 strains of L. pneumophila and Legionella spp. Glucosyl transferase activity of 3 types (Lgt1, Lgt2 and Lgt3) was determined by western blotting and PCR method.
Results: Lgt1 and Lgt3 were detected only in members of L. pneumophila independently of isolation source and were absent in Legionella spp. strains. Lgt2 is absent in Legionella spp. strains and is detected in not all the L. pneumophila strains. Comparative analysis of detection frequency of Lgt2 in clinical strains and L. pneumophila strains isolated from the environment showed that the protein is detected in clinical strains more frequently (46%) compared with strains from the environment (23%).
Conclusion: Lgt1 and Lgt3 as species specific markers could be used for practical purposes for identification of L. pneumophila strains. High frequency of Lgt2 isolation in clinical strains of L. pneumophila isolated from lung tissue in lethal cases of legionellosis compared with strains isolated from the environment requires a more detailed study of functional activity and substrate specificity of the glucosyl transferase.