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Veterinary bacteriology: information about important bacteria
Veterinary bacteriology


Species/Subspecies: Rickettsia rickettsii
Category: Motile
Etymology: Genus namn: Named after Howard T. Ricketts, who showed which organism caused Rocky Mountain spotted fever, which resulted in his death
Species epithet: see Genus namn.
Significance:  [Of minor importance]   
Taxonomy:
Phylum
Proteobacteria
Class
Alphaproteobacteria
Order
Rickettsiales
Family
Rickettsiaceae 
Genus
Rickettsia
Type Strain: Smith = ATCC VR-149.
Macromorphology (smell): Cannot be cultivated on cell free substrates (for instance agar plates).
Micromorphology: Short (paired) motile rods (0.2-0.3 x 0.3-2 µm).R. rickettsia exhibits actin-based motility (see references 154 and 155 below).
Gram +/Gram -:G-
Metabolism: Aerobic
Catalase/Oxidase:
Fermentation of carbohydrates: Is not used for identification of Rickettsia spp.
Spec. Char.: Is obligate intracellular because the plasma membrane is leaky and the bacteria require correct osmolarity and constant supply of nutrients.
Vector: American dog tick or wood tick (Dermacentor variabilis) and Rocky Mountain wood tick (Dermacentor andersoni).
Disease:Rocky Mountain spotted fever
Hosts: Dog, man
Clinical Picture:
Genome Sequence:
Acc-noStrainSize (bp)Genome
NC_009882 Sheila Smith 1 257 710 1c + 0 

16S rRNA Seq.:
Acc-noStrainNumber of NTOperon
L36217 1440 

Taxonomy/phylogeny:
 
About 30 species have been described within the genus Ricketsia. This genus is relatively closely related to other genera within the orderRickettsialas (Anaplasma, Ehrlichia and Neorickettsia).
Legislation: R. rickettsia belongs to category C as a potential bioterrorism agent according to NIAID
Comment:Intracellular in endothelial cells where it is primarely growing freely in the cytoplasm. An evolutionary interesting bacterium, because its ancestors invaded cells and formed the mitochondria by endosymbiosis. Can use ATP from the hostcell, but also synthesize ATP by oxidative phosphorylation.
Reference(s): No. 154, 155
Updated:2020-10-28

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The revised taxonomy of the mollicutes

The revised taxonomy of mollicutes (mycoplasmas) has now been introduced on VetBact, which means that many of the species have been given new genus names or moved to another higher taxon. 

Published 2021-11-25. Read more...

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