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What is Which of the following factor is mainly respon-sible for virulence in Streptococcus : and explain in detail?
M Protein

It is major virulence factor of group A Strep. pyogenes.
It is hair like projection of cell wall.
It is of 80 types (basis of Griffith classification) so immunity is type specific.
M protein is also found in Group G streptococci.

Remember :

Carbohydrate is used as the basis of Lancefields classification.
Streptokinase or fibrolysin and streptodornase or DNAse liquefy pus so used in enzymatic debridement