Streptococcus Pyogenes (Group A Strep)

Colonizes URT of healthy children and adultscolonization is transientsurvives well on dry surfaces and fomitesinfection occurs when organism penetrates normal defensestypically requires high infectious dosesequelae very severehistorically, related for puerperal fever (acquired during childbirth)

CapsuleM proteinlipoteichoic acidF proteinC5a peptidaseStreptococcal pyrogenic exotoxins (Spe)StreptolysinsStreptokinasesDNases

Non immunogeniccontains hyaluronic acid similar to that of our connective tissue

(surface protein) 100+ typesmajor antigenic variation (stays 1 step ahead)antiphagocytic - phagocytosis cannot happen unless develop antibodies against M proteininterferes with alternate complement pathwayfacilitates invasion into epithelial tissues

(found in cell wall) adhesionused to bind fibronectin in host tissue

Adhesionused to bind epithelial tissues

Destroys C5a which is a complement proteindisables activation of complement

Produced by lysogenic strains (carried by bacteriophage)4 distinct exotoxins (heat labile) - SpeA, SpeB, SpeC, SpeFcan serve as superantigen (leading to sepsis and shock)causes rash in scarlet feverinvolved in streptococcal TSS and necrotizing fasciitis

Types S and O serve as hemolysinsS - nonimmunogenic, lyse all types of blood cells and lysosomes in phagocytes - worse than OO - immunogenic, oxygen labile, antibodies readily made against these types

At least 2 types - A and Bbreak down fibrin, dissolving clotsfacilitates spreading

Depolymerize DNAreduces viscosity of pusfacilitates spreading

Pharyngitisscarlet feverskin infectionsnecrotizing fasciitisstreptococcal toxin shock syndrome (TSS)Rheumatic feverglomerulonephritis

Aka strep throat or tonsilitismost common ages 5-15transmission is respiratory dropletsincubation: 2-4 dayssymptoms: sore throat, 102 fever, pustules in throat****need treatment - immune system will resolve but should receive treatment within 10 days

Complication of pharyngitisseen when infecting strain is lysogenized and carries a pyrogenic exotoxin (Spe)symptoms of pharyngitis and:rash (red checks, pale around mouth) - eventually moves to chest and extremities with texture of sandpaper)strawberry tongue - white/yellow coating which later falls off to reveal rashlasts 5-7 days, rash disappears and skin desquamates complications: 104 fever and symptoms persist can lead to brain damage, protein and cell denaturing

Impetigo- pustules develop and crust over -S. aureus can cause this too-problems with secondary infectionscellulitis-acute infection of skin and deeper tissues-usually fever-lots of inflammation and swellingboth usually caused by tiny break in skin