Streptococcal Infections: 11.16.2022. Study Questions Flashcards
Describe the typical scenario of strep throat
transmission?
carriers?
symptoms (4)
infectious or not?
droplet transmission, mainly 5-15 y/o
<5% of people are carriers
sore, red throat
whitish pus on tonsils
enlarged lymph nodes
No cough
very infectious
Considering that strep throat is typically a fairly minor illness, why is it important that the infection is treated with antibiotics?
Post-Streptococcal Sequelae is very dangerous
- rheumatic fever
- glomerulonephritis
- PANDAS
Describe the typical scenario of rheumatic fever
Post-Streptococcal Sequelae
damage to tissues (heart valves) caused by accumulation of bacteria. need antibiotics to flush it out.
Describe the typical scenario of glomerulonephritis
Post-Streptococcal Sequelae
damage to kidneys caused by accumulation of immune complexes (antigen bound to antibody)
Why is M protein significant medically? (3)
- antibodies to it are protective
- over 80 different antigenic types
- antibodies to it are associated with rheumatic fever
What are the functions of Protein F, Protein M, and protein G of S. pyogenes?
Fixes, Messes, Grabs
F: responsible for attachment to host cells
M: interferes with phagocytosis by causing breakdown of complement C3b, an opsonin
G: binds to Fc portion of antibody thereby interfering with opsonization
How does the capsule protect S. pyogenes from the immune system?
invisibility cloak from immune system
What diseases are caused by toxigenic strains of Group A strep?
scarlet - strep - csiitis
- Scarlet fever
- Streptococcal toxic shock
- Necrotizing fasciitis “flesh-eating disease)
What are superantigens?
trigger an extreme response in the immune system
What diseases involve superantigens?
Diseases Caused by Toxigenic Strains of Grp A Streptococci
- scarlet fever
- Streptococcal toxic shock
- Necrotizing fasciitis (flesh-eating disease)
How is scarlet fever different from rheumatic fever?
- caused by?
rheumatic fever:
- caused by Group A post-Streptococcal sequelae, cross-reacting antibodies
scarlet fever:
- caused by toxigenic strains of Group A Streptococci, erythrogenic toxin
Provide a disease scenario for Streptococcal flesh eating disease
- appear suddenly, are very serious
- severe pain at wound site
- swelling, discoloration, pain, stretched skin, fever, confusion, fatigue and vomiting. spread can lead to shock and death
Does there need to be a visible wound for flesh eating disease to occur?
nope
Fill out disease tables for all Streptococcal diseases
what toxin causes scarlet fever?
erythrogenic toxin
