Legionellales

Legionellales is an order of proteobacteria. It includes two families, the Legionellaceae and the Coxiellaceae. The bacteria in this order are gram-negative and are primarily intracellular parasites.

Legionellaceae

The Legionellaceae family includes the genus Legionella, which contains over 60 species. These bacteria are found in freshwater environments and can cause Legionnaires' disease and Pontiac fever when inhaled by humans. The most well-known species is Legionella pneumophila, which is the primary cause of Legionnaires' disease.

Coxiellaceae

The Coxiellaceae family includes the genus Coxiella, which contains the species Coxiella burnetii. This bacterium is the cause of Q fever, a disease that can be transmitted to humans by inhalation of dust contaminated by infected animals.

Pathogenesis

The bacteria in the Legionellales order are primarily intracellular parasites, meaning they live and reproduce inside host cells. They are able to survive and multiply within macrophages, a type of white blood cell. This allows them to evade the immune system and cause disease.

Treatment

Treatment for diseases caused by Legionellales bacteria typically involves antibiotics. For Legionnaires' disease, the antibiotics macrolides, quinolones, and rifampin are commonly used. For Q fever, the antibiotic doxycycline is typically used.

See also

• Legionella
• Coxiella
• Legionnaires' disease
• Q fever

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  Legionella Plate 01