In a school, a child had an abscess on the lower leg, Swab taken revealed gram-positive beta-hemolytic streptococci, and these were bacitracin sensitive. School physician observed that similar organism was isolated from throats of many other children. Which of the following is true statement with regards to this patient

Several protein antigens have been identified in the outer pa of the cell wall of Streptococcus. Streptococcus pyogenes can be typed based on: M protein: The most impoant protein used for typing as well as for virulence. The M protein is heat and acid stable but susceptible to tryptic digestion. It can be extracted by Lancefield's acid extraction method and typing is done with type-specific sera. Reference: Textbook of Microbiology; Anathanarayan and paniker's; 10th edition; Page no: 213