<prompt> In a school child had abscess on 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?Difference in surface protein can differentiate the pathogenic bacteria from the pharyngeal culture bacteriaComponent C carbohydrate can differentiate the pathogenic bacteria from the throat culture bacteriaMEG 3 positive are throat culture streptococciDepending on M protein the cutaneous pathogenic bacteria can be differentiated from the pharyngeal culture bacteria  <response>: Ans. is d i.e., Depending on M protein the cutaneous pathogenic bacteria can be differentiated from the pharyngeal culture bacteria Ref: Sherris Medical Microbiology, p. 716 Bacitracin sensitive gram positive beta hemolytic cocci is streptococcus pyogenes. Two most common sites of infection with streptococci are the upper respiratory tract pharyngitis, tonsillitis and the skin impetigo. S. pyogenes causing skin infection impetigo tend to belong to different M serotypes than those associated with respiratory infection pharyngitis.The M protein types of a S. pyogenes most commonly associated with skin infection impetigo are different from those causing respiratory infection pharyngitis. 