False about Streptococcus pyogenes: (A) Causes necrotizing fasciitis, (B) Beta haemolytic, (C) M protein is the virulence factor, (D) Resistant to bacitracin
Answer is D. A convenient method for the identification of S.pyogenes is based on Maxted's observation that they are more sensitive to bacitracin than other streptococci. a filter paper disc of 0.04 U is applied on the surface of an inoculated blood agar. After incubation, a wide zone of inhibition is seen with S.pyogenes, but not with other streptococci. Ref: Textbook of microbiology; Ananthanarayan and paniker's; 10th edition; Pg:217, 218