Streptococcus pyogenes is a spherical gram-positive bacteria that grows in long chains an is the cause of Group A streptococcal infections. S. pyogenes displays group A antigen on its cell wall and beta-hemolysis when cultured on blood agar plate. S. pyogenes typically produces large zones of beta-hemolysis, the complete disruption of erythrocytes and the release of hemoglobin, and it is therefore called Group A (beta-hemolytic) Streptococcus (abbreviated GAS). Streptococci are catalase-negative. In ideal conditions, Streptococcus pyogenes has an incubation period of approximately 10 days.