Legionella
From Free net encyclopedia
{{Taxobox
| color = lightgrey
| name = Legionella
| image = Legionella_Plate_01.png
| image_width = 240px
| image_caption = Legionella sp. under UV illumination.
| regnum = Bacteria
| phylum = Proteobacteria
| classis = Gamma Proteobacteria
| ordo = Legionellales
| familia = Legionellaceae
| genus = Legionella
| genus_authority = Brenner et al. 1979
| subdivision_ranks = Species
| subdivision =
Legionella adelaidensis
Legionella anisa
Legionella beliardensis
Legionella birminghamensis
Legionella bozemanii
Legionella brunensis
Legionella busanensis
Legionella cherrii
Legionella cincinnatiensis
Legionella donaldsonii
Legionella drancourtii
Legionella drozanskii
Legionella erythra
Legionella fairfieldensis
Legionella fallonii
Legionella feeleii
Legionella geestiana
Legionella gratiana
Legionella gresilensis
Legionella hackeliae
Legionella israelensis
Legionella jamestowniensis
Legionella jordanis
Legionella lansingensis
Legionella londiniensis
Legionella longbeachae
Legionella lytica
Legionella monrovica
Legionella moravica
Legionella nautarum
Legionella oakridgensis
Legionella parisiensis
Legionella pneumophila
Legionella quateirensis
Legionella quinlivanii
Legionella rowbothamii
Legionella rubrilucens
Legionella sainthelensi
Legionella santicrucis
Legionella shakespearei
Legionella spiritensis
Legionella steigerwaltii
Legionella taurinensis
Legionella tucsonensis
Legionella wadsworthii
Legionella waltersii
Legionella worsleiensis
}}
Legionella is a Gram negative bacterium, including species that cause legionellosis or Legionnaires' disease, most notably L. pneumophilia <ref>Template:Cite book</ref>. Legionella are common in many environments, with at least 48 species and 70 serogroups identified. On the side-chains of the cell wall are carried the bases for the somatic antigen specifity of these organisms. The chemical composition of these side chains both with respect to components as well as arrangement of the different sugars determines the nature of the somatic or O antigen determinants, which are such important means of serologically classifying many Gram-negative bacteria.
Pathogenesis
Legionella species are the causative agent of the human Legionnaires' disease and the lesser form Legionnaires', Pontiac fever. Legionella transmission is via aersols—the inhalation of mist droplets containing the bacteria. Common sources may include cooling towers, domestic hot water systems, fountains, and similar diseminators that tap into a public water supply. Natural sources of Legionella include freshwater ponds and creeks. Person-to-person transmission of Legionella has not been demonstrated.<ref>Template:Cite book</ref>
Once inside a host, the bacteria incubation may take up to 2 weeks. Initial symptoms are flu-like, including fevers, chills, and dry coughs. Advanced stages of the disease causes problems with the gastrointestinal tract and the nervous system and lead to diarrhea and nausea. Other advanced symptoms of pneumonia may also present.
However, the disease is generally not a threat to most healthy individuals, and only tend to lead to harmful symptoms in those with a compromised immune system and the elderly. Due to this nature, it is actively checked for in the water systems of hospitals and nursing homes. In the United States, the disease affects between 8,000 to 18,000 individuals a year.
References
<references/>da:Legionella de:Legionellen es:Legionella it:Legionella ja:レジオネラ no:Legionella nn:Legionella-bakterie sv:Legionella zh:軍團菌屬