Resistance Mechanisms

Question 1

What are some resistance mechanisms against ß-lactams?

Answer 1

Exclusion:
- Outer membrane porin size

Altered Target:
- Mutant and new PBPs

Inactivation:
- ß-lactamases

Question 2

What are some resistance mechanisms against glycopeptides (vancomycin)?

Answer 2

Exclusion:
- Thickened outer wall

Altered Target:
- D-Ala D-Lac

Question 3

What are some resistance mechanisms against Aminoglycosides?

Answer 3

Exclusion:
- Oxidative transport required

Altered Target:
- Ribosomal binding site mutations

Inactivation:
- Adenylases, acetylases, phosphorylases

Question 4

What are some resistance mechanisms against Macrolides and Clindamycin?

Answer 4

Exclusion:

• OM porin size
• MDR pump

Altered Target:
- Methylation of rRNA

Inactivation:

• Phosphotransferase
• Esterase

Question 5

What are some resistance mechanisms against for chloramphenicol?

Answer 5

Altered Target:
- Methylation of rRNA

Inactivation:
- Acetyltransferase

Question 6

What are some resistance mechanisms against Tetracycline?

Answer 6

Exclusion:
- MDR pump

Altered Target:
- New protein protects ribosomal binding site

Question 7

What are some resistance mechanisms against fluroquinolones?

Answer 7

Exclusion:

• MDR pump
• permeability mutation

Altered Target:
- Mutant Topoisomerase

Question 8

What are some resistance mechanisms against Rifampin?

Answer 8

Altered target:

- Mutant RNA polymerase

Question 9

What are some resistance mechanisms against Folate inhibitors?

Answer 9

Altered Target:

• New Dihydropteroate synthetase
• Altered DHFR reductase