Video - Streptococcus pyogenes (Group A Strep)

Streptococcus pyogenes, often called group A streptococcus (GAS), is a gram-positive, beta-hemolytic, and bacitracin-sensitive bacteria. Group A streptococcus normally colonize the pharynx, vagina, or the skin, where they're part of the normal flora, but in some cases, they may take advantage of a weakened immune system and causes infections like strep pharyngitis, scarlet fever, impetigo, necrotizing fasciitis. Infections due to certain strains of this bacteria can involve certain bacterial toxins, leading to scarlet fever or toxic shock syndrome. Group A streptococcus is also associated with post-infectious sequelae, like acute rheumatic fever and post-streptococcal glomerulonephritis. Treatment involves antibiotics like penicillin G, cephalosporins such as ceftriaxone, and macrolides such as azithromycin.