Legionella pathogenicity

Legionella pneumophila is the most frequent species among the Legionellaceae. In the environment it infects protozoa. When transmitted to humans it can cause influenza-like infection called Pontiac-fever or pneumonia, especially in immunocompromised patients. In cases of human infection it enters alveolar macrophages by coiling or conventional phagocytosis and replicates within a so called replicative phagosom that did not fuse with the endosome and lysosome. Legionella strains isolated from different water systems may vary in the capability to infect macrophages. Therefore the assessment of the risk at least fo…