Coccal infections

Question 1

how does staph aureaus escape from the host response

Answer 1

Protein A - on the surface of Staph aureus, it binds to the Fc of IgG, it allows the S. aureus to escape specific antibody

Question 2

how do the staph aureus damage tissues

Answer 2

cytolysins; pyogenic inflammation; alterations in coagulation; enzymatic digestion of host tissue (hyaluronidase, fibrinolysin, lipases, DNAas)

Question 3

how does Strep pyogenes escape host immune defenses

Answer 3

the M-protein. The m protein is antiphagocytic and has a hypervariable outer bit. It thus can exist in multiple serotypes

Question 4

What are the outcomes of streptococcal pharyngitis

Answer 4

Recovery 3-5 days
Scarlet Fever
Suppurative sequelae (otitis media, sinusitis, abscess, etc.)
nonsuppurative sequelae (rheumatic fever, actue glomerulonephritis)

Question 5

What is the manifestation of scarlet fever and the etiology

Answer 5

manifestation: rash (red, rough sandpapery rash on trunk and extremities), desquamation of tonge (goes from white tongue to red strawberry tongue). Face is flush, except around the mouth creating a circumoral pallor
etiology: erythrogenic exotoxin

Question 6

What is the manifestation and etiology of acute rheumatic fever

Answer 6

polyarthritis, pancarditis (valve damage), chorea, erythema marginatum.
etiology: autoimmune, Aschoff bodies, M-protein association
ABX will help with this

Question 7

what is the manifestation and etiology of postreptococcal acute glomerulonephritis

Answer 7

edema, increased BP, rusty urine
etiology: immune complex deposition.
ABX are ineffective