|Description:||This Gram-stained photomicrograph, which had been subjected to a carbol fuchsin counterstain, revealed the presence of numerous Gram-negative Legionella pneumophila bacteria. The bacteria depicted here were taken from a Knoxville-1 strain sample, and had been cultivated on buffered charcoal yeast extract (BCYE) agar medium.|
Legionnaires' disease is caused by a type of bacteria called Legionella. The bacteria got its name in 1976, when many people who went to a Philadelphia convention of the American Legion suffered from an outbreak of this disease, a type of pneumonia (lung infection). Although this type of bacteria was around before1976, more illness from Legionnaires' disease is being detected now. This is because we are now looking for this disease whenever a patient has pneumonia.