<prompt> A boy with skin ulcer on leg, culture revealed beta hemolysis. School physician said that similar hemolysis was seen in organism from sorethroat, what is the similarity between both?A protein is same for bothC carbohydrate antigen is differentC carbohydrate antigen is the sameStrain causing both are same  <response>: Ans. c C-carbohydrate antigen is the same 13 hemolytic streptococci causing both skin infection and sore throat can be none other than Group A streptococci. The basis by which Lancefield classified streptococci in to groups A-H and K-V is c carbohydrate. So, different Group A streptococci have same c carbohydrate. In group A, c carbohydrate is rhannose - N-acetyl glycosamine. Based on the M protein Griffith divided Group A carbohydrate in to 80 subtypes. Sore throat strains and skin strains of streptococci differ in their M-protein. Skin infection is usually caused by M-types . 