Antibiotics

Question 1

How are prokaryotes (bacteria) different in structure to eukaryotes (human cells)?

Answer 1

DNA not nuclei bound, may be present as plasmids too.
Cell wall can either be gram positive (peptidoglycan) or negative (LPS).
May have other special features (flagellum, type 4 pili).

Question 2

What are the 5 main mechanisms of antimicrobials?

Answer 2

Inhibit cell wall synthesis 
Inhibit nucleic acid synthesis 
Stopping metabolite production 
Inhibiting cell membrane synthesis 
Inhibiting protein synthesis

Question 3

Name a class of drugs which prevent cell wall synthesis ?

Answer 3

Beta-lactams

Vancomycin

Question 4

Name an antimicrobial which prevents DNA/RNA synthesis ?

Answer 4

Fluoroquinolones

Rifamycins

Question 5

Name an antimicrobial which works to inhibit folate synthesis ?

Answer 5

Trimethoprim

Sulfonamides

Question 6

Name a antimicrobial which prevents cell membrane synthesis ?

Answer 6

Daptomycin

Question 7

Name a antimicrobial which inhibits protein synthesis

Answer 7

Linezolid
Tetracyclines
Macrolides
Aminoglycosides

Question 8

What is the difference between a bactericidal and a bacteriostatic?

Answer 8

Bactericidal- destroy/killing bacteria

Bacteriostatic - stopping divisions and replication of bacteria, slowing growth. Relies on immune system clearance.

Question 9

What type of resistance mechanisms have bacteria developed?

Answer 9

Efflux pumps
Immunity and bypass
Target modification
Inactivation enzymes

Question 10

Why must some drugs be monitored ?

Answer 10

Narrow therapeutic window
Risk of toxicity vs Maximum effect of antibiotic
MIC

Question 11

What is the difference between time dependant and concentration dependant bacteria?

Answer 11

Time- long half lives are beneficial

Concentration - certain amount at binding sites required

Question 12

Why might antibiotics be used?

Answer 12

Short term for management of bacterial infections

Prophylaxis for high risk procedures

Question 13

What are the drugs that are co-prescribed as co-amoxiclav and why are they prescribed together?

Answer 13

amoxicillin - acts on beta lactam cell walls
Clavulanic acid- inhibits effect of some beta-lactamase enzymes
Therefore synergistic effect

Question 14

What might determine the choice of antibiotic?

Answer 14

• source of infection
• trends/previous population results
• high risk group
• hepatic or renal impairment
• pregnancy
• allergy/reactions

Question 15

What are the 5 I’s of anti-microbial stewardship?

Answer 15

Identify- (abroad,blood born, colonised, diarrhoea/vomit, expectorating (cough), funny looking rash)
Isolate 
Investigate
Inform
Initiate treatment

Question 16

Aciclovir is used for?

Answer 16

Antiviral - HSV, but other conditions too

Dose is dependant on first or relapse presentation, immunocompromised