Legionella pneumophila: Difference between revisions

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*''[[Legionella]]'' is non-fermentative and is unable to [[hydrolysis|hydrolyse]] [[gelatin]] or produce [[urease]].
*''[[Legionella]]'' is non-fermentative and is unable to [[hydrolysis|hydrolyse]] [[gelatin]] or produce [[urease]].
*At least 46 species and 70 serogroups of ''[[Legionella]]'' have been identified.  
*At least 46 species and 70 serogroups of ''[[Legionella]]'' have been identified.  
Legionella grow on buffered charcoal yeast enriched with L-cysteine <ref name="pmid16751507">{{cite journal| author=Ewann F, Hoffman PS| title=Cysteine metabolism in Legionella pneumophila: characterization of an L-cystine-utilizing mutant. | journal=Appl Environ Microbiol | year= 2006 | volume= 72 | issue= 6 | pages= 3993-4000 | pmid=16751507 | doi=10.1128/AEM.00684-06 | pmc=1489648 | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=16751507  }} </ref>
*The natural habitat of Legionella is freshwater, where they often live within protozoa such as Vermamoeba vermiformis, Acanthamoeba spp., Tetrahymena pyriformis, and Naegleria spp <ref name="pmid11018138">{{cite journal| author=Swanson MS, Hammer BK| title=Legionella pneumophila pathogesesis: a fateful journey from amoebae to macrophages. | journal=Annu Rev Microbiol | year= 2000 | volume= 54 | issue=  | pages= 567-613 | pmid=11018138 | doi=10.1146/annurev.micro.54.1.567 | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=11018138  }} </ref>. It utilizes a similar method to enter and infect phagocytes.                                                                                         


==Life Cycle==
==Life Cycle==

Revision as of 05:14, 20 April 2022

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Legionella pneumophila
TEM image of L. pneumophila
TEM image of L. pneumophila
Scientific classification
Kingdom: Bacteria
Phylum: Proteobacteria
Class: Gamma Proteobacteria
Order: Legionellales
Family: Legionellaceae
Genus: Legionella
Species: L. pneumophila
Binomial name
Legionella pneumophila
Brenner DJ, Steigerwalt AG, McDade JE 1979
This page is about microbiologic aspects of the organism(s).  For clinical aspects of the disease, see Legionellosis.

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]

Overview

L.pneumophila is a ubiquitous aquatic organism that thrives in warm environments (32°- 45°C). L. pneumophila is a pleomorphic, aerobic, catalase-positive, oxidase-positive, non-spore-forming, non-capsulated, motile, Gram-negative bacteria. Although Legionella is categorized as a Gram-negative bacterium, it stains poorly to Gram stain due to its unique lipopolysaccharide-content in the outer psuedospamodulating leaflet of the outer cell membrane.

Microbiological Classification

Microbiological Characteristics

Legionella grow on buffered charcoal yeast enriched with L-cysteine [2]

  • The natural habitat of Legionella is freshwater, where they often live within protozoa such as Vermamoeba vermiformis, Acanthamoeba spp., Tetrahymena pyriformis, and Naegleria spp [3]. It utilizes a similar method to enter and infect phagocytes.

Life Cycle

  • There are two major phases to the life cycle.
  • The first is called the replicative phase. During this period, the bacteria are nonmotile and have a low toxicity.
  • In the second phase, called the infectious phase, the bacteria are shorter and thicker.

Gallery

Colorized scanning electron micrograph (SEM) depicted a large grouping of Gram-negative Legionella pneumophila bacteria under 8000x magnification.Courtesy of Janice Haney Carr, Public Health Image Library[4]
Colorized scanning electron micrograph (SEM) depicted a large grouping of Gram-negative Legionella pneumophila bacteria under 10,000x magnification.Courtesy of Janice Haney Carr, Public Health Image Library[5]
Legionella micdadei bacteria using TATLOCK conjugate in egg yolk sac suspension, DFA-stained photomicrograph with positive HEBA stain.Courtesy of Ann Herbert, Public Health Image Library[6]

References

  1. Ryan KJ; Ray CG (editors) (2004). Sherris Medical Microbiology (4th ed. ed.). McGraw Hill. ISBN 0-8385-8529-9.
  2. Ewann F, Hoffman PS (2006). "Cysteine metabolism in Legionella pneumophila: characterization of an L-cystine-utilizing mutant". Appl Environ Microbiol. 72 (6): 3993–4000. doi:10.1128/AEM.00684-06. PMC 1489648. PMID 16751507.
  3. Swanson MS, Hammer BK (2000). "Legionella pneumophila pathogesesis: a fateful journey from amoebae to macrophages". Annu Rev Microbiol. 54: 567–613. doi:10.1146/annurev.micro.54.1.567. PMID 11018138.
  4. Haney Carr, Janice. "Public Health Image Library". www.cdc.gov. Retrieved Jan 15 2016. Check date values in: |access-date= (help)
  5. Haney Carr, Janice. "Public Health Image Library". www.cdc.gov. Retrieved Jan 15 2016. Check date values in: |access-date= (help)
  6. Herbert, Anne. "Public Health Image Library". www.cdc.gov. Retrieved Jan 15 2016. Check date values in: |access-date= (help)