| Legionella pneumophila is a gram-negative bacterium and a facultative intracellular pathogen. Legionella pneumophila is ubiquitously found in fresh water environments, where it replicates in its protozoan hosts. Human inhalation of aerosol droplets contaminated by Legionella pneumophila may result in Legionnaires' disease caused by infection of human alveolar macrophages. Legionella pneumophila multiply in both protozoan and mammalian cells by inhibiting phagosome-lysosome fusion as well as remodeling of L. pneumophila-containing vacuoles into organelles resembling the Endoplasmic Reticulum (Iturbe-Ormaetxe, Burke et al.) in support of bacterial growth. Both processes are regulated by L. pneumophila effectors injected by the Type IV secretion apparatus Dot/Icm during infection. These effectors are predicted to target diverse host cellular pathways to re-direct L. pneumophila trafficking for the biogenesis of ER-like vacuoles that support intracellular replication of L. pneumophila. |
