Clinical 8.2

Question 1

Where is the binding site and what are the biological effects of virbio cholera?

Answer 1

Bowel mucosa

Activation fo adenylate cyclase resulting in secretory diarrhoea

Question 2

Where is the binding site and what are the biological effects of Clostridium tetani?

Answer 2

NMJ

Decrease in NT release from inhibitory neurons causing septic paresis

Question 3

Where is the binding site and what are the biological effects of Clostridium botulinum?

Answer 3

Motor end plate

Decrease in peripheral, pre-synaptic ACh release causing flaccid paralysis

Question 4

What make a host susceptible to infection?

Answer 4

Anatomical and physical changes
Changes in normal flora
Prosthetic devices
Immune response: non specific, cell mediate, antibody responses
Congenital deficits
Acquired - Dugs, HIV, haematological disorders, splenectomy, chronic medical conditions

Question 5

What are the virulence factors of staph aureus?

Answer 5

Capsule - evade phagocytosis
Peptidoglycan - endotoxin like activity, leukocyte chemoattractant, inhibits phagocytosis
Teichoic Acid - binds to fibronectin
Protein A - Inhibits antibody mediated clearance by binding to IgG Fc receptors
Coagulase - converts fibrinogen to fibrin
Catalase - Catalyses removal of hydrogen peroxide
Hyaluronidase - hydrolyses hyaluronic acid
Fibrinolysin - dissolves fibrin clots
Lipases - hydrolyses lipids
Nucleases - Hydrolyses DNA