- The bacterium that causes Legionnaires' disease. This disease is due specifically to the bacterium Legionella pneumophila found in plumbing, shower heads and water-storage tanks. Outbreaks of Legionella pneumonia have been attributed to evaporative condensers and cooling towers. The bacterium thrives in the mist sprayed from air-conditioning ducts and so it can infest an entire building or airplane. Travelers are especially vulnerable in the closed space within a plane. Legionnaires' disease can cause a massive pneumonia associated with collapse of the respiratory function. It can be an overwhelming and sometimes fatal illness. The disease was first identified as a sequel of the 1976 convention of the American Legion in some of the Legionnaires who had attended the convention. It was therefore named Legionnaires' disease. The distinguished surgeon/writer Richard Selzer has recounted his own near-fatal experience with Legionnaires' disease in "Raising the Dead. A Doctor's Encounter with His Own Mortality" (Whittle/Viking, New York, 1993, ISBN 0-670-85414-X).
* * *A genus of aerobic, motile, nonacid-fast, nonencapsulated, Gram-negative bacilli (family Legionellaceae) that have a nonfermentative metabolism and require l-cysteine HCl and iron salts for growth; they are water-dwelling, airborne-spread, and pathogenic for humans. Over 40 species have been identified; the type species is L. pneumophila.- L. micdadei a bacterial species that may be acid-fast, and that causes Pittsburgh pneumonia, a variant of Legionnaires disease. Accounts for approximately 60% of L. pneumonias other than those caused by L. pneumophila. SYN: Pittsburgh pneumonia agent.- L. pneumophila a bacterial species that is the primary etiologic agent of Legionnaires disease; believed to grow in plumbing systems or in standing water in ventilation systems. The type species of the genus L..
* * *le·gion·el·la .lē-jə-'nel-ə n1) cap a genus of gram-negative rod-shaped bacteria (family Legionellaceae) that includes the causative agent (L. pneumophila) of Legionnaires' disease
* * *Le·gio·nel·la (le″jə-nelґə) [from legionnaires' disease] a genus of gram-negative, aerobic, rod-shaped bacteria of the family Legionellaceae, made up of motile, pleomorphic organisms that require cysteine and iron for growth. Their normal habitat is lakes, streams, and moist soil, but they have also been found as contaminants in human habitations, where they can cause legionellosis, a pneumonialike disease spread by the airborne route. The type species is L. pneumoґphila.
Medical dictionary. 2011.