Group A streptococci

Streptococcus pyogenes, a Group A Streptococcus, is a Gram-positive bacterium causing pharyngitis and various streptococcal diseases like scarlet fever, cellulitis, and necrotizing fasciitis. It produces numerous virulence factors including streptolysins and exotoxins. Diagnosis involves cultural, microscopic, and serological tests. Treatment includes antibiotics like penicillin, and no vaccines exist currently.