Legionellales

Legionellales is an order of Gram-negative bacteria. The most well-known genus within this order is Legionella, which contains the species Legionella pneumophila. This bacterium is the causative agent of Legionnaires' disease, a severe form of pneumonia, and Pontiac fever, a milder flu-like illness. Legionella bacteria are commonly found in freshwater environments, such as lakes, streams, and ponds, and can also proliferate in artificial water systems like cooling towers, hot tubs, and plumbing systems. They are facultative intracellular parasites, meaning they can survive and replicate both inside host cells and in the environment. Transmission to humans typically occurs through inhalation of contaminated aerosols. Other genera within the Legionellales order include Coxiella, which causes Q fever, and Rickettsiella. These bacteria share certain genetic and physiological characteristics, including a reliance on host cells for replication. Research into Legionellales focuses on understanding their pathogenesis, developing diagnostic methods, and creating effective treatments and prevention strategies.