Strep Pyogenes

Question 1

strep pyogenes identifiers

Answer 1

gram +
cocci in chains
beta hemolysis
catalase -
bacitracin sensitive

Question 2

non suppurative infections caused by GAS

Answer 2

acute rheumatic fever

acute post-strep glomerulonephritis

Question 3

toxin mediated infections caused by GAS

Answer 3

scarlet fever

TSS

Question 4

hyaluronic acid capsule

Answer 4

surface protein
camouflages cells
antiphagocytic propertines

Question 5

peptidoglycan

Answer 5

surface protein
stablilizes structure
endotoxin

Question 6

streptolysin S

Answer 6

surface protein

pokes holes in RBC membrane (beta hemolysis)

Question 7

streptokinase

Answer 7

surface protein

activates plasmin to degrade clots

Question 8

M protein

Answer 8

surface protein
binds to keratinocytes
antiphagocytic- blocks complement system, blocks phagocytosis/opsonization
binds fibrinogen

Question 9

lipoteichoic acid

Answer 9

surface protein

sticks to mucous membranes

Question 10

adhesions

Answer 10

surface protein

Fn binding proteins bind fibronectin

Question 11

M like proteins

Answer 11

surface protein
antiphagocytic
bind plasma inhibitors and IgG

Question 12

C5a peptidase

Answer 12

surface protein

cleaves C5a complement and prevents neutrophil recruitment

Question 13

streptolysin O

Answer 13

secreted

toxin detected by ASO antibody titer

Question 14

hyaluronidase

Answer 14

secreted

hydrolyzes HA to get it deeper into tissue

Question 15

pyogenic exotinx

Answer 15

secreted- cause scarlet fever and skin rash

Question 16

NADase

Answer 16

secreted

inhibits internalization and killing

Question 17

DNAase

Answer 17

secreted

degrades free DNA in pus

Question 18

superantigens

Answer 18

secreted

nonspecific activation of T cells causing a huge inflammatory response

Question 19

main disease caused by strep pyogenes

Answer 19

pharyngitis (viral is most common)

ARF

Question 20

epidemiology of pharyngitis

Answer 20

5-15yo
peaks in late winter
person to person spread
asymptomatic carriers

Question 21

diagnosis of pharyngitis

Answer 21

throat culture to determine strep or viral

plate culture- beta hemolysis

Question 22

treatment of pharyngitis

Answer 22

penicillin

macrolides

Question 23

jones criteria for ARF

Answer 23

migratory arthritis
carditis
subcutaneous nodules
syndeham's chorea
erythema marginatum

Question 24

signs of scarlett fever

Answer 24

scarlitinal rash- red on body

strawberry tongue

Question 25

basis of molecular mimicry

Answer 25

antigens “mimic” host proteins by sharing antigens

Question 26

what is acute glomerulonephritis

Answer 26

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

Question 27

PANDAS

Answer 27

autoimmune neuropsychiatric disorder in kids associated with strep
chorea, OCD
due to cross reactive antibodies for brain

Question 28

strep pyoderma

Answer 28

impetigo
superficial skin infection in kids 2-5s
spread due to poor hygiene
vesicles –> pustules –> crusty amber lesions

Question 29

strep cellulitis

Answer 29

spreading inflammation of skin and subcutaneous tissue

due to burns, wounds, or surgical infections

Question 30

necrotizing fascitis

Answer 30

highly invasive fascia infection
high mortality
treat by debridement, fasciotomy, or amputation