Streptococci. Streptococcus Gram positive spherical or ovoid cells, arranged in chains or pairs Non spore forming, Non-motile Some species form capsules of polysaccharides or hyaluronic acid Small, non pigmented colonies
toxic shock syndrome, scarlet fever.
1-Blood agar: very small, white to grey colonies approximately 1mm in diameter surrounded by a zone of beta hemolysis.
2- Sensitive to bacitracin.
3-Serological test: streptolysin O stimulate Anti- streptolysin O (ASO) antibody:ASO test) is indicative of previous pharyngeal infection.
Not optochin sensitive
4-The Viridans Streptococci: