Vancomycin + Lipoglycopeptides

Question 1

What drug is this?

Answer 1

• vancomycin

Question 2

What drug is this?

Answer 2

• Teicoplanin

Question 3

What is the mechanism of action of vancomycin?

Answer 3

• vancomycin binds to the peptidyl side chain D-ala-Dala terminus in the peptidoglycan precursor before it cross-links.
• Because vanc has a high binding affinity to the peptidoglycan, the transpeptidase cannot perform the reaction for cross-linking
• Vanc also inhibits the transglycosylation step in peptidoglycan synthesis

• generally, vanc inhibits gram-positive cell wall biosynthesis

Question 4

What is the difference between the mechanism of vancomycin compared to penicillins?

Answer 4

• vancomycin binds to the peptidoglycan and prevents the transpeptidase from getting to it
• penicillins interact with the transpeptidase to inactivate it

• They both generally prevent crosslinking

Question 5

What is the spectrum of activity for vancomycin?

Answer 5

• active against gram-positive bacteria
• bacterium with an MIC 4 ug/mL is considered a susceptible strain

• streptococci are also generally susceptible

Question 6

What is the mechanism of bacterial resistance to vancomycin?

Answer 6

• Resistance is due to a mutation of the peptidoglycan cell wall precursor.
• D-ala-Dala mutates to D-ala-D-lactate.
• Vancomycin does not inhibit the transpeptidase when the substrate is D-ala-D-lactate because vanc has 1000 times less affinity for this precursor.

Question 7

What is the route of administration for vancomycin?

Answer 7

IV

Question 8

What are the main therapeutic uses of vancomycin?

Answer 8

• clostridium difficile pseudomembranous colitis
• methicillin-resistant staphylococcus aureus (MRSA)

Question 9

What are the toxic effects of vancomycin?

Answer 9

• hypersensitivity (skin rash, potential anaphylaxis)
• nephrotoxicity
• ototoxicity

Question 10

What drug is this?

Answer 10

• oritavancin

lipoglycopeptide

Question 11

What is the mechanism of action of oritavancin, telavancin, dalbavancin?

Answer 11

• inhibits transpeptidation and transglycosylation

Question 12

What is the spectrum of activity of oritavancin, telavancin, dalbavancin?

Answer 12

active against a broad spectrum of gram-positive bacteria, including MRSA

Question 13

What drug is this?

Answer 13

telavancin

lipoglycopeptides

Question 14

What drug is this?

Answer 14

dalbavancin

Question 15

What are the half-lives of vancomycin, telavancin, dalbavancin, and oritavancin?

Answer 15

• vancomycin –> 4-6 h
• telavancin –> 7-9 h
• dalbavancin –> 204 h
• oritavancin –> 245 h