Strep Pyogenes Flashcards
strep pyogenes identifiers
gram + cocci in chains beta hemolysis catalase - bacitracin sensitive
non suppurative infections caused by GAS
acute rheumatic fever
acute post-strep glomerulonephritis
toxin mediated infections caused by GAS
scarlet fever
TSS
hyaluronic acid capsule
surface protein
camouflages cells
antiphagocytic propertines
peptidoglycan
surface protein
stablilizes structure
endotoxin
streptolysin S
surface protein
pokes holes in RBC membrane (beta hemolysis)
streptokinase
surface protein
activates plasmin to degrade clots
M protein
surface protein
binds to keratinocytes
antiphagocytic- blocks complement system, blocks phagocytosis/opsonization
binds fibrinogen
lipoteichoic acid
surface protein
sticks to mucous membranes
adhesions
surface protein
Fn binding proteins bind fibronectin
M like proteins
surface protein
antiphagocytic
bind plasma inhibitors and IgG
C5a peptidase
surface protein
cleaves C5a complement and prevents neutrophil recruitment
streptolysin O
secreted
toxin detected by ASO antibody titer
hyaluronidase
secreted
hydrolyzes HA to get it deeper into tissue
pyogenic exotinx
secreted- cause scarlet fever and skin rash
NADase
secreted
inhibits internalization and killing
DNAase
secreted
degrades free DNA in pus
superantigens
secreted
nonspecific activation of T cells causing a huge inflammatory response
main disease caused by strep pyogenes
pharyngitis (viral is most common)
ARF
epidemiology of pharyngitis
5-15yo
peaks in late winter
person to person spread
asymptomatic carriers
diagnosis of pharyngitis
throat culture to determine strep or viral
plate culture- beta hemolysis
treatment of pharyngitis
penicillin
macrolides
jones criteria for ARF
migratory arthritis carditis subcutaneous nodules syndeham's chorea erythema marginatum
signs of scarlett fever
scarlitinal rash- red on body
strawberry tongue
basis of molecular mimicry
antigens “mimic” host proteins by sharing antigens
what is acute glomerulonephritis
inflammatory disorder of renal glomeruli that happens after a skin strep infection–immune complexes of IgG/C3 accumulate on the basement membrane and damage it
PANDAS
autoimmune neuropsychiatric disorder in kids associated with strep
chorea, OCD
due to cross reactive antibodies for brain
strep pyoderma
impetigo
superficial skin infection in kids 2-5s
spread due to poor hygiene
vesicles –> pustules –> crusty amber lesions
strep cellulitis
spreading inflammation of skin and subcutaneous tissue
due to burns, wounds, or surgical infections
necrotizing fascitis
highly invasive fascia infection
high mortality
treat by debridement, fasciotomy, or amputation
