Biology 431 Gram (+) Cocci Chapters 22-24

Staphylococcus Major groups - coagulase (+) aureus vs. (-) others. External Structures Capsule - polysaccharide, 11 serotypes, antiphagocytic Peptidoglycan endotoxin-like - fever, WBC, complement Teichoic acid binds host mucosal fibronectin receptors Protein A - binds IgG, prevents Ab clearance

Toxins - mostly aureus Cytotoxins (A, B, D, G) - hemolytic, mostly WBC/RBC Exfoliative - protease, target skin desmosomes… causes SSSS/neonates; impetigo/nosocomial, AIDS… Enterotoxins (50%) - 8 different, acid/heat-stable, Sag TSS (15%) - tampon-associated, invasive and SAg

Flesh-Eating/Invasive Enzymes - most aureus Catalase: neutralize H2O2, metabolic or phagocytic Hyaluronidase: hydrolyze connective tissue, spread Lipase: survival in sebaceous areas, invasion Fibrinolysin/Staphylokinase: dissolve fibrin clots Penicillinase: plasmid-passed antibiotic resistance Coagulase: covered in lab

Other aureus Diseases - Most Hematogenous Enterocolitis - C. difficile-like, long-term antibiotics Bacteremia - bacteria in blood, 50% nosocomial Endocarditis - 50% fatal rapid deterioration Pneumonia - several, all associated with abscesses Osteomyelitis - bone infection, pain, high fever

Non-aureus Diseases UTI - mostly saprophyticus, lab Endocarditis - mostly epidermidis and lugdunensis… Native heart valves - malformed, genetic, disease Nosocomial plastic devices, prosthetics - 1 year later

Streptococcus Hemolysis subgroups - lab External Structures - pyogenes Capsule - polysaccharide, Lancefield (surface A-G)… pyogenes = Group A - 10% weight, NAG/rhamnose M Protein types, antiphagocytic/opsonization Lipoteichoic acid binds host mucosal fibronectin

Other Virulence Factors - pyogenes Pyrogenic Exotoxins - SAg, toxic shock, rash, fever… Streptolysin - hemolytic for RBC, WBC - more in lab Streptokinase - lysis of fibrin clots, disease spread DNAse - nucleases, target pus to reduce viscosity C5a Peptidase - destroys key complement protein Outcomes - pharyngitis, varying skin infections, Scarlet & Rheumatic Fever/Arthritis, glomerulonephritis.

agalactiae - Group B, beta hemolytic Historically puerperal sepsis - childbirth, war wounds Currently - neonatal septicemia, pneumonia, meningitis Group B Carbohydrate - NAG/rhamnose/galactose Colonize lower GI & GU, 10-30% pregnant women GU 60% infants colonized, increases with premature or prolonged delivery; post-delivery infection possible.

pneumoniae - Nongroupable, alpha hemolytic Diseases: pneumonia, sinusitis, otitis, meningitis Polysaccharide capsule - 90 types, antiphagocytic IgA protease - digests IgA, prevents binding Pneumolysin - digests cholesterol, pores Pneumococcal vaccine, anti-capsule for 23 strains Viridans group also nongroupable - cavities, endocarditis.

Enterococcus Will not cover extensive list of others, Table Enterococcus - Virulence, Disease, Treatment Surface adhesin protein - bind GI and vaginal mucosa Secrete - hemolysins, proteases, bacteriocins Inherently resist many antibiotics; serious nosocomial... UTI, surgical (peritoneum/heart), blood (endocarditis) Careful antibiotic selection, use - new drug development gallinarum more prominent human GI flora; faecalis more disease-associated.