MOA Of Antibiotics

Question 1

What is selective toxicity?

Answer 1

*antibiotic must be effective against pathogen but have no effect against host

Question 2

How to B lactams inhibit cell wall synthesis ?

Answer 2

Bind PBP’s- disrupt peptidoglycan cell wall

Question 3

How do glycopeptides (vancomycin) inhibit cell wall synthesis?

Answer 3

Disrupt cross linkage of peptidoglycan

Question 4

Why do antibiotics inhibit protein synthesis in bacteria but not mammalian cells?

Answer 4

The difference in ribosomes- bacteria have 70S

Question 5

What is the MOA of macrolides? (Erythromycin, clarithromycin)

Answer 5

*bind to 50S
*block translocation
*bacteriostatic

Question 6

How does tetracyclines work?

Answer 6

*bind to 30S
*inhibit aa-tRNA binding to a site
*bacteriostatic

Question 7

How does inhibition of nucleic acid synthesis work?

Answer 7

*inhibit DNA gyrase
*stops supercoiling

Question 8

Why does inhibition of folic acid synthesis affect bacteria?

Answer 8

*folic acid essential for DNA and RNA synthesis

Question 9

What are the 5 ways antibiotics work?

Answer 9

*inhibit cell wall synthesis- disrupt peptidoglycan synthesis or cross linkage
*inhibit protein synthesis- produces defective proteins- opens cell membrane into channels, lets more antibiotic in
*inhibit nucleic acid synthesis- inhibit DNA gyrase synthesis- stops supercoiling
*inhibit folic acid synthesis- essential in bacteria for RNA and RNA synthesis
*alternation of cell membrane- leakage of nucleic acid- cell death