Legionella

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Related to legionellae: Legionella pneumonia

Legionella

 [le″jun-el´ah]
a genus of gram-negative, aerobic rod-shaped bacteria, the cause of legionellosis. Species include L. micda´dei, the etiologic agent of Pittsburgh pneumonia, and L. pneumo´phila, the etiologic agent of legionnaires' disease and pontiac fever.

Legionella

(lē'jŭn-el'lă),
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 dwell in water, spread in air, and are pathogenic for humans. Over 40 species have been identified; the type species is Legionella pneumophila.

Legionella

/Le·gion·el·la/ (le″jah-nel´ah) a genus of gram-negative, aerobic, rod-shaped bacteria (family Legionellaceae), normal inhabitants of lakes, streams, and moist soil; they have often been isolated from cooling-tower water, evaporative condensers, tap water, shower heads, and treated sewage. L. micda´dei is the causative agent of Pittsburgh pneumonia. L. pneumo´phila is the causative agent of legionnaires' disease.

Le·gion·el·la

(lējŏ-nelă)
A genus of aerobic, motile, non-acid-fast, nonencapsulated, gram-negative bacilli; they dwell in water and are borne by air; pathogenic for humans. The type species is L. pneumophila.

Le·gion·el·la

(lējŏ-nelă)
A genus of aerobic, motile, non-acid-fast, nonencapsulated, gram-negative bacilli; they dwell in water and are borne by air; pathogenic for humans. The type species is L. pneumophila.

Legionella

(lē´jənel´ə),
n a genus of areobic, motile, non acid-fast, nonencapsulated, gram-negative bacilli that have a nonfermentative metabolism. They are water dwelling, airborne spread, and pathogenic for man.
L. pneumophila,
n the causative agent of Legionnaires' disease.
References in periodicals archive ?
14 12 6 12 8 pneumophila species Total all 22 19 17 19 14 Legionellae Legionella Type # in Q2 (Apr-Jun) '04 '05 '06 '07 '08 L.
Water samples from the homes of six culture-positive patients were negative for legionellae by culture, but samples from 10 of 24 CTs and one of three decorative fountains in downtown Providence were positive for Lp-1.
Culturing respiratory secretions for legionellae and testing urine for presence of antigen are not routinely performed for patients with community-acquired pneumonia.
Although legionellae can be cultured in up to 40% of CTs, these devices are rarely associated with outbreaks of LD (1).
Legionellae are fastidious organisms that are not readily recovered from routine diagnostic media; indeed, an American College of Pathologists' survey indicates that 32% of clinical microbiology laboratories could not grow a pure culture of L.
Serotyping, serogrouping, typing, and subtyping legionellae are technically challenging.
In the positive samples, the mean number of legionellae was 1.
6% of domestic hot water samples, with a mean number of legionellae in positive samples of 1.
Recent studies, however, found that contamination was consistent throughout the year, both in terms of the species of legionellae isolated and in the concentration of organisms (18), suggesting that the occurrence of Legionnaires' disease most frequently in the summer is not necessarily linked to a higher water contamination.
Conditions that affect the proliferation of legionellae include sludge, scale, rust, algae, and organic particulates thought to provide nutrients for growth.
Clinical cases have also occurred because of the inhalation of water droplets containing the blue-white fluorescent group of legionellae, e.
However, if the appropriate detection systems are in place to culture and detect nonculturable organisms, it is likely that legionellae will be found in distribution systems (12).