Streptococcus viridans
From Free net encyclopedia
{{Taxobox | color = lightgrey | name = Streptococcus viridans | image = Streptococcus_viridans_01.png | image_width = 200px | regnum = Eubacteria | phylum = Firmicutes | classis = Bacilli | ordo = Lactobacillales | familia = Streptococcaceae | genus = Streptococcus }}
Streptococcus viridans is a pseudo-taxonomic term for a large group of generally non-pathogenic, commensal streptococcal bacteria that are α-hemolytic and produce a green (hence the name viridans) coloration on blood agar plates.
Viridans can be differentiated from Streptococcus pneumoniae using an optochin test, as S. viridans is optochin resistant. Viridans streptococci also lack either the polysaccharide-based capsule typical of S. pneumoniae or the Lancefield antigens of the pyrogenic members of the genus. The organisms are most abundant in the mouth and one member of the group, S. mutans, is the etiologic agent of dental caries. Others may be involved in other mouth or gum infections. If they are introduced into the bloodstream they have the potential of causing endocarditis, particularly in individuals with damaged heart valves.
Site and Sources:
- Mouth
- Skin
- Nasopharynx
- Heart
- Oropharynx
The diagnosis can be done by letting it grow on blood agar.