- Gram-negative aerobe, cause of legionellosis or Legionnaires’ disease.
- Common environmental organisms found in warm water sources (e.g., 32°- 45°C temperature range as in warm ponds, air chillers, industrial air conditioning systems, water systems include storage and hot water).
- Commonly infect free-living amoeba and other ciliated protozoa as natural hosts for this bacteria.
- Legionella spp. include >60 species and 70 serotypes.
- Most are capable of causing human disease.
- L. pneumophila serogroup 1: most common, accounting for 80-90% of cases of Legionnaires’ disease.
- The appellation is based on the first recognition of the disease in a pneumonia epidemic at the American Legion Convention in Philadelphia in 1976.
- Others: less frequent, occasional causes of legionellosis
- L. pneumophila serogroups 2-15
- L. micdadei
- Sometimes referred to as the "Pittsburgh pneumonia agent."
- Alternatively, the organism has been called Tatlockia micdadei
- L. dumoffi
- L. longbeachae
- L. bozemanii
- Legionella do not grow on the most commonly used microbiologic media; buffered charcoal yeast extract (BCYE) agar [Fig 1] is preferred.
- Legionella are poorly visualized with Gram stain but may be seen as a Gram negative [Fig 2]. Silver stains such as Warthin-Starry or Dieterle stains [Fig 3] are preferred.
- It may weakly stain acid-fast but loses this characteristic when grown in culture.
- An intracellular pathogen, effective drugs in animal models include fluoroquinolones, macrolides, TMP/SMX, rifampin and doxycycline.
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Last updated: April 16, 2023
Auwaerter, Paul G. "Legionella Species." Johns Hopkins ABX Guide, The Johns Hopkins University, 2023. Pediatrics Central, peds.unboundmedicine.com/pedscentral/view/Johns_Hopkins_ABX_Guide/540308/all/Legionella_species.
Auwaerter PG. Legionella species. Johns Hopkins ABX Guide. The Johns Hopkins University; 2023. https://peds.unboundmedicine.com/pedscentral/view/Johns_Hopkins_ABX_Guide/540308/all/Legionella_species. Accessed June 4, 2023.
Auwaerter, P. G. (2023). Legionella species. In Johns Hopkins ABX Guide. The Johns Hopkins University. https://peds.unboundmedicine.com/pedscentral/view/Johns_Hopkins_ABX_Guide/540308/all/Legionella_species
Auwaerter PG. Legionella Species [Internet]. In: Johns Hopkins ABX Guide. The Johns Hopkins University; 2023. [cited 2023 June 04]. Available from: https://peds.unboundmedicine.com/pedscentral/view/Johns_Hopkins_ABX_Guide/540308/all/Legionella_species.
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TY - ELEC T1 - Legionella species ID - 540308 A1 - Auwaerter,Paul,M.D. Y1 - 2023/04/16/ BT - Johns Hopkins ABX Guide UR - https://peds.unboundmedicine.com/pedscentral/view/Johns_Hopkins_ABX_Guide/540308/all/Legionella_species PB - The Johns Hopkins University DB - Pediatrics Central DP - Unbound Medicine ER -