Permissiveness of freshly isolated environmental strains of amoebae for growth of Legionella pneumophila

• Published in: FEMS microbiology letters Vol. 363; no. 5; p. fnw022
• Main Authors: Dupuy, Mathieu, Binet, Marie, Bouteleux, Celine, Herbelin, Pascaline, Soreau, Sylvie, Héchard, Yann
• Format: Journal Article
• Language: English
• Published: England Oxford University Press 01.03.2016; Wiley-Blackwell
• Subjects: Acanthamoeba; Acanthamoeba - microbiology; Amoeba; Bacteria; Biochemistry, Molecular Biology; Cellular Biology; Legionella pneumophila; Legionella pneumophila - growth & development; Legionnaires' disease bacterium; Life Sciences; Microbiology; Naegleria; Naegleria - microbiology; Phagocytes; Phagocytosis; Protozoa; Selectivity; Strains (organisms); Temperature; Water Microbiology; infection; environment; Legionella; amoeba; water
• ISSN: 1574-6968; 0378-1097; 1574-6968
• DOI: 10.1093/femsle/fnw022

Legionella pneumophila is a pathogenic bacterium commonly found in water and responsible for severe pneumonia. Free-living amoebae are protozoa also found in water, which feed on bacteria by phagocytosis. Under favorable conditions, some L. pneumophila are able to resist phagocytic digestion and even multiply within amoebae. However, it is not clear whether L. pneumophila could infect at a same rate a large range of amoebae or if there is some selectivity towards specific amoebal genera or strains. Also, most studies have been performed using collection strains and not with freshly isolated strains. In our study, we assess the permissiveness of freshly isolated environmental strains of amoebae, belonging to three common genera (i.e. Acanthamoeba, Naegleria and Vermamoeba), for growth of L. pneumophila at three different temperatures. Our results indicated that all the tested strains of amoebae were permissive to L. pneumophila Lens and that there was no significant difference between the strains. Intracellular proliferation was more efficient at a temperature of 40°C. In conclusion, our work suggests that, under favorable conditions, virulent strains of L. pneumophila could equally infect a large number of isolates of common freshwater amoeba genera. Our study shows that Legionella pneumophila is able to multiply in a wide range of freshly isolated amoebal hosts.