Streptococcus pyrogene Streptococcus agalacticiae

Question 1

virulence factors of strep pyrogenes

Answer 1

M protein - interferes with opzonization
fibronectin - binding protein F
lipoteichoic acid- attachment to host cells
capsule- prevent phagocytosis
hyaluronidase- breaks down hyaluronic acid that hold cell together
C5a peptidase- inhibits macrophage and neutrophils chemotaxis

Question 2

Infection and disease caused by group b/ strep agalactiae

Answer 2

neonatal disease
endometritis
wound infection
UTI
bacteremia
pneumonia
skin & soft tissue infection

Question 3

Infections caused by strep pyrogene/group a

Answer 3

pharyngitis - strep throat
scarlett fever - diffuse rash start from chest
rheumatic fever - inflammed heart, joint, blood vessel
cellulitis - infection of skin, subcunteneous tissue
necrotizing fasciitis - flesh eating disease
step toxic shock syndrome - multiorgan systematic infec. similar to staph but with fasciitis
pyoderma- skin infection (pulus) blisters

Question 4

strep pyrogene toxins and enzymes

Answer 4

1. exotoxins (spe) -acts a superantigen and interacts with macrophages and helper T cells = release of cytokines= strep toxic shock
2. steptolysin S- oxygen stable, lyses erythrocytes, leukocytes, platelets, produced in serum, responsible for B hemolysis
3. streptolysin O- oxygen labile, capable of lyses blood and cultured cells
4. streptokinase a&b- cleavage of plasminoge. lyse blood clot and fibrin deposit cause rapid spread of strep pyrogene

Question 5

types of hemolysis

Answer 5

alpha (partial lysis)
beta (complete lysis)
gamma (clear no lysis)

Question 6

what are the carbohydrates A-U important for?

Answer 6

differentiates streptococcus based on carb composition in the cell wall

Question 7

Where is group a normally found and how does it spread?

Answer 7

staph pyrogenes
normally found in upper resp tract
spread by person to person (respiratory droplets), break in the skin (direct), fomite, vectors

Question 8

what is the initial host parasite interaction of strep pyrogenes

Answer 8

1. hyaluronic acid capsule
2. M protein
3. C5a peptidase

Question 9

what is hemolysis?

Answer 9

destruction of blood cells