Anti fungals - Morris

Question 1

Fungal cell wall is bound together by

Answer 1

Beta glucans

Question 2

What is the steroid that maintains cell membrane permeability?

Answer 2

Ergosterol

Question 3

What enzyme strings together D-glucose molecules in cell wall?

Answer 3

1,3 B-glucan synthase

Question 4

Mechanism of action of AMPHOtericin B - Polyene

Answer 4

• Binds to ergosterol
• causing holes
  Leaky cell - K+ leaves - cell dies

Question 5

Side effects of Ampho B

Answer 5

Damages human cells
Leads to rigor fevers
NEPHROTOXIC - related to dose and duration

Question 6

How do you avoid the nephrotoxicity of AmphoB

Answer 6

Slow infusion rate

or add liposomes

Question 7

Azoles mechanism of action - more static than cidal

Answer 7

Prevent generation of ergosterol 
inhibit 14a demethylase - also  P450 enzyme
alter cell membrane permeability
toxic intermediates damage cell
DRUG interactions a problem

Question 8

Resistance to azoles due to

Answer 8

Overproduction of target enzyme
Altering the enzyme
Efflux 
Alter permeability
deactivate the drug

Question 9

Echinocandins MOA - end in fungin! - all expensive

Answer 9

Bind and inhibit 1,3 B glucan synthase, inhibit cell wall production
fungal version of beta lactams

Question 10

Resistance to Echnicandins due to

Answer 10

Changes in the structure of 1,3 Beta glucan synthase