T1: Antimicrobial Susceptibility Testing of Anaerobes

Question 1

“treatment of disease based upon experience”

Answer 1

Definition of empiric therapy

Question 2

current treatment for anaerobic infections

Answer 2

1. Abscess drainage and surgical debridement of necrotic tissue
2. Selection of appropriate antimicrobial agents if needed

Question 3

What 3 groups of anaerobes are known to be more resistant to antimicrobials and may require susceptibility testing

Answer 3

1. Bacteroides fragilis group
2. Prevotella
3. Fusobacterium

Question 4

What 3 antimicrobials are generally effective for anaerobic infections

Answer 4

1. Carbapenems
2. Beta-lactam/Beta-lactamase inhibitor combinations
3. Metronidazole

Question 5

What susceptibility testing method is NOT appropriate for anaerobes?

Answer 5

Disk diffusion

Question 6

What is the reference method for anaerobe susceptibility testing?

Answer 6

Agar dilution

Question 7

Three susceptibility testing methods that are appropriate for anaerobe susceptibility testing

Answer 7

1. Agar dilution
2. Broth microdilution
3. E-test strip

Question 8

Agar dilution limitations

Answer 8

• only practical for large-scale testing
• swarming isolate cause problem
• not cost effective for few isolates

Question 9

Broth microdilution limitations

Answer 9

• only for B. fragilis group