5 min DENTISTRY

Streptococcus pyogenes  streptococci  cocci means - round or spherical shaped bacteria  streptos means - twisted or coiled in appearance  the name pyogenes is given because it is found in suppurative lesions ( that is pus-forming diseases) Therefore the name streptococci pyogenes. FEATURES  - either aerobic, facultative anaerobes or obligate anaerobes   - aerobic and facultative anaerobes alone have hemolytic properties - based on the hemolytic properties we have alpha, beta and gamma bacteria  -the alpha bacteria show partial hemolysis therefore a green discoloration is seen  -the beta hemolytic bacteria show complete hemolysis and colorless zone is seen in the blood agar culture medium  - whereas the gamma type of bacteria does not show any hemolytic properties and are non-hemolytic  T he beta hemolytic streptococci are again divided into 20 groups by Lancefield  and these 20 groups are classified based on these C carbohydrate antigen present on the cell wall of the bacteria. Lance