Chances are that you’ve heard of Pneumonia at some point throughout your life. However, it is likely that you aren’t familiar with Legionella. Legionella Pneumophila is an aerobic bacilli that is responsible for causing both lobal and interstitial Pneumonia.

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First identified at the American Legion Convention, Legionella is a monopolar flagellum that grows both inside and outside of host cells.

Legionella is both oxidase and catalase positive. Although it is a gram negative rod, when this bacteria is gram stained, it typically stains poorly. To properly stain Legionella, scientists must use a silver stain on buffered charcoal yeast extract agar. If there is no time to wait for a culture, Legionella can also be identified through a urine antigen test.

In addition to Pneumonia, Legionella can cause Legionnaires disease. Symptoms of this disease are gastrointestinal issues, nausea, and abdominal pain. Another mild illness caused by this bacteria is Pontiac Fever, which has similar symptoms to the flu.

Legionella causes infection when aerosolized bacteria is inhaled, although it is not considered an airborne pathogen. Thankfully, Legionella cannot be spread from person to person. If you do find yourself infected with Legionella, you can treat this with Fluoroquinolone and Macrolides.


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