B and D B and D G, F – mutans mutans

M protein M protein M protein M protein fibrinogen fibrinogen r r r peptidoglycan peptidoglycan r r r IgG IgG Complement Complement IMMUNE IMMUNE NON-IMMUNE NON-IMMUNE Toxins Enzymes Hemolysis alpha beta gamma Pathogenesis of S pyogenes infections. • affect all ages peak incidence at affect all ages peak incidence at 5-15 years of age 5-15 years of age • non-invasive non-invasive – pharyngitis pharyngitis – skin infection, impetigo skin infection, impetigo • invasive bacteremia invasive bacteremia – toxic shock-like syndrome toxic shock-like syndrome – flesh eating bacteria flesh eating bacteria – pyrogenic toxin pyrogenic toxin • Scarlet fever Scarlet fever  rash rash  erythrogenic toxin erythrogenic toxin • rheumatic fever rheumatic fever  inflammatory disease inflammatory disease  life threatening life threatening  chronic sequalae chronic sequalae  fever fever  Heart Heart  Joints Joints  rheumatic NOT rheumatoid arthritis rheumatic NOT rheumatoid arthritis • Acute glomerulonephritis Acute glomerulonephritis immune complex disease of kidney immune complex disease of kidney Rheumatic fever -etiology Rheumatic fever -etiology  M protein M protein – cross-reacts heart myosin cross-reacts heart myosin – autoimmunity autoimmunity  cell wall antigens cell wall antigens – poorly digested poorly digested in vivo in vivo – persist indefinitely persist indefinitely Post-infectious diagnosis serology Post-infectious diagnosis serology • antibodies to streptolysin O antibodies to streptolysin O • important if delayed clinical sequelae important if delayed clinical sequelae occur occur • superantigen superantigen • T cell mitogen T cell mitogen • activates immune activates immune system system Group B streptococcus - Group B streptococcus - identification identification • neonatal meningitis neonatal meningitis • septicemia septicemia • transmission transmission – vaginal flora vaginal flora    hemolysis hemolysis • hippurate hydrolysis hippurate hydrolysis • CAMP reaction CAMP reaction – increases increases   hemolysis of hemolysis of S. aureus S. aureus Group D streptococcus Group D streptococcus • Growth on bile esculin agar Growth on bile esculin agar – black precipitate black precipitate • 6.5 saline 6.5 saline • grow grow – enterococci enterococci • no growth no growth – non-enterococci non-enterococci • distantly related to other streptococci distantly related to other streptococci • genus genus Enterococcus Enterococcus • gut flora gut flora – urinary tract infection urinary tract infection • fecal contamination fecal contamination – opportunistic infections opportunistic infections • particularly endocarditis particularly endocarditis • most common most common E. S. faecalis E. S. faecalis • resistant to many antibiotics resistant to many antibiotics – including vancomycin including vancomycin • terminal D-ala replaced by D-lactate terminal D-ala replaced by D-lactate Viridans streptococci Viridans streptococci • diverse species diverse species • oral oral • dental caries dental caries    hemolytic and negative for other tests hemolytic and negative for other tests • non-groupable. non-groupable. • includes includes S. mutans S. mutans – endocarditis endocarditis – tooth extraction tooth extraction

S. pneumoniae - diplococci

• capsule: capsule: • pneumolysin pneumolysin : : • Surface protein adhesinand Surface protein adhesinand secretory IgA protease. secretory IgA protease. • Teichoic acid and the Teichoic acid and the Peptidoglycan fragment, Peptidoglycan fragment, phosphorylchorine . phosphorylchorine . • leading cause pneumonia leading cause pneumonia – particularly young and old particularly young and old – after damage to upper after damage to upper respiratory tract respiratory tract e.g. following viral infection e.g. following viral infection • bacteremia bacteremia • meningitis meningitis • middle ear infections otitis media middle ear infections otitis media