Infection 10

Question 1

What is a bactericidal antimicrobial?

Answer 1

Substance that kills bacteria

Question 2

What is a bacteriostatic antimicrobial?

Answer 2

Biological or chemical agent that prevents bacteria reproducing

Question 3

What are the 3 main mechanisms of action of antibacterials?

Answer 3

Interfere with cell wall synthesis - Beta-lactams, glycopeptides
interfere with protein synthesis (toxins are proteins) - Tetracyclines, Aminoglycosides, macrolides
Interfere with nucleic acid synthesis - Quinolones

May also interfere with cell membrane function - polymixins

Question 4

What is the aim of antimicrobials?

Answer 4

Effective prevention and treatment of infections whilst minimising resistance, unwanted side effects and avoidable costs

Question 5

What are the potential unwanted effects of antibiotics?

Answer 5

GI upsets
Allergies
Haematological disturbances
Organ toxicity
Super-infections

Question 6

What are the 2 areas of antimicrobial usage?

Answer 6

Intrinsic empiric therapy
Specific or definitive treatment
Prophylaxis

Question 7

How is an antibiotic selected?

Answer 7

“Best guess”: Clinical diagnosis > probable pathogen > predicted sensitivities

Specific: Specimens > pathogens > sensitivity testing

Question 8

What influences your choice of antibiotic?

Answer 8

Spectrum of activity
Site of infection
Patient factors
Guidance
Hospital/primary care guidance

Question 9

When would combined therapies of antibiotics be used?

Answer 9

Broad spectrum when pathogen unknown or multiple pathogens present
Prevent emergence of resistant strains
Enhanced activity - addition or synergy (difficult to treat)