Legionella pneumophila are rod-shaped, strictly aerobic, gram negative bacteria. They are slow-growing bacteria and can take 3 to 5 days to produce visible colonies which appear in ground-glass coloured border morphology .
Legionella pneumophila can multiply rapidly in contaminated water sources, for example, cooling towers for large buildings, air conditoner systems, fountains, even baths and showers. The bacteria can be transmitted to human and thrive human's lung through inhalation of contaminated water droplets, leading to pneumonia such as Legionaires' disease. However, Legionella bacteria are not contagious as the bacteria cannot be transmitted from person to person .
The symptoms of Legionnaires' disease will develop 2 to 14 days after exposure to the bacteria which will normally begin with headache, chills and muscle pain. This is followed by more severe symptoms which include high fever, fatigue, persistent cough, breathing difficulty and chest pain . Detection of Legionella pneumophila can be done by urine test, blood test and chest X-ray . In addition, several antibiotics work to kill Legionella bacteria 
- ↑ http://emedicine.medscape.com/article/220163-workup
- ↑ http://www.nhs.uk/Conditions/Legionnaires-disease/Pages/Causes.aspx
- ↑ http://www.nhs.uk/Conditions/Legionnaires-disease/Pages/Symptoms.aspx
- ↑ http://www.nhs.uk/Conditions/Legionnaires-disease/Pages/Diagnosis.aspx
- ↑ http://www.nhs.uk/Conditions/Legionnaires-disease/Pages/Treatment.aspx