Infection

Question 1

Staph. aureus virulence factors?

Answer 1

1. coagulase: local blood clot formation, limiting PMN access
2. haemolysin: RBC osmotic lysis
3. Panton-Valentine leukocidin: pore-forming toxin causing neutrophil lysis - abscess formation

Question 2

Antibiotics for MSSA and MRSA?

Answer 2

MSSA: flucloxacillin
MRSA: vancomycin

Question 3

C. difficile exotoxins?

Answer 3

1. enterotoxin A - excessive fluid secretion (diarrhoea), inflammatory response and some cytopathic effect
2. cytotoxin B - disrupts protein synthesis, cytoskeleton disorganisation

Both glycosylate and inactivate Rho-family GTP binding proteins.

Question 4

C. difficile gram stain appearance?

Answer 4

Gram positive rods

Question 5

Causative agent, presentation and management of infectious mononucleosis?

Answer 5

Organism = Epstein-Barr Virus

Presentation - classical trial:
- fever
- pharyngitis
- cervical lymphadenopathy 
Can also present with headache, malaise and splenomegaly.

Management: avoid alcohol, take paracetamol