Which of the following statement about Legionella pneumoniae is TRUE?

Legionella pneumophila is a gram negative bacillus. It is known to cause Legionnaire disease and Pontiac fever. It can be diagnosed by culturing sputum, tracheal aspirates or bronchoscopic specimens. Urine immunoassay for Legionella antigen is 70% sensitive and is highly specific. It can also be isolated from a lung biopsy material. Legionnaire disease is an acute, severe pneumonia that is frequently fatal in immunocompromised patients. Pontiac fever is a mild, flu like illness that spares the lungs and is characterized by fever, headache, myalgia, and ahralgia. Ref: Ogle J.W., Anderson M.S. (2012). Chapter 42. Infections: Bacterial & Spirochetal. In W.W. Hay, Jr., M.J. Levin, R.R. Deterding, J.J. Ross, J.M. Sondheimer (Eds), CURRENT Diagnosis & Treatment: Pediatrics, 21e.