Antimicrobial Susceptibility Testing of Anaerobes

Question 1

Objective 1: Define empiric therapy

Answer 1

The treatment of disease based upon experience

Question 2

Objective 2: Describe the current treatment of anaerobic infections

Answer 2

1. Abscess drainage and surgical debridement of necrotic tissue
2. Selection of antimicrobials

Question 3

Objective 3: List three (3) groups (or genera) of anaerobes which are known to be more resistant to antimicrobials and may require susceptibility testing

Answer 3

1. Bacteroides fragillis group
2. Prevotella
3. Fusobacterium

Question 4

Objective 4: Recognize the three (3) antimicrobials (or class of antimicrobials) which are generally effective for anaerobic infections

Answer 4

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

Question 5

Objective 5: Recognize the susceptibility testing method that is NOT appropriate for anaerobes

Answer 5

Disk diffusion

Question 6

Objective 6: Recognize the reference method for anaerobe susceptibility testing

Answer 6

CLSI (Agar dilution)

Question 7

List the three (3) susceptibility testing methods that are appropriate for anaerobe susceptibility testing. Include any limitations for each method

Answer 7

1. Agar dilution
   
   • Swarming isolates causes issues
   • Not cost effective for few isolates
2. Broth microdilution
   
   • Only for B. fragilis group
3. E-test strip (epsilometer)