Streptococcus pyogenes B. Knauss F2013 Modified by DYH Streptococcus pyogenes Gram positive cocci Pathogenic human skin flora Group A streptococci Capable of beta-hemolysis; Complete clearing of red blood cells Figure 2, S. pyogenes plated on blood agar Phylum Firmicutes Order Lactobacillales Family Streptococcaceae Utilize pili to attach to host Figure 1; http://textbookofbacteriology.net/normalflora.html Figure 2; http://textbookofbacteriology.net/pathogenesis_4.html

Streptococcus pyogenes Pathogenesis B. Knauss F2013 Modified by DYH Streptococcus pyogenes Pathogenesis Respiratory and skin infections, namely tonsillitis and pneumonia Spread by direct physical contact Capsule forming Capsule is non antigenic so it chemically matches the host’s connective tissue and is not targeted for phagocytosis Figure 3, S. pyogenes cells appear black with a white “halo” around them Contain M proteins, fimbrial proteins, fibronectin-binding proteins, and streptokinases on cell surface for adhesion to host M proteins also aide in resistance to phagocytosis Contain streptolysins, streptokinases, and hyaluronidase to break down host tissue and cause inflammation Several million cases of strep throat and impetigo are reported each year in the United States Severely susceptible to penicillin Figure 3; http://textbookofbacteriology.net/BSRP.html