Inhibitors of Cell Wall Synthesis

Question 1

Which class shouldn’t be used in combination with a beta lactam?

Answer 1

carbapenams (cuse increase in beta lactamases)

Question 2

Fosfomycin MoA

Answer 2

inhibits conversion of NAG to NAM by inhibiting enolpyruvate transferase enzyme

Question 3

Cycloserine MoA

Answer 3

inhibits incorporation of D-alanine into pentapeptide by inhibiting alanine racemase - also inhibits creation of d-alanine dipeptide by inhibiting its ligase Inhibits conversion of L-ala to D-ala*

Question 4

Bacitracin MoA

Answer 4

inhibits the binding of NAM to the cell membrane by inhibiting the dephosphorylation step in the cycling of the lipid carrier bactoprenol

Question 5

Vancomycin MoA

Answer 5

binds to the D-ala-D-ala terminus noncovalently, and the the pentaglycine bridge of the pentapeptide - inhibits transglycosylation and transpeptidation, preventing elongation of peptidoglycan

Question 6

Vancomycin resistance

Answer 6

bacteria can alter the D-ala-D-ala strain to prevent binding by replacing D-alanine with D-lactate. This is done by enterococci and VRSA strains. The other way is through VISA strains thickening the cell wall with increased D-ala residue

Question 7

Dalbavancin

Answer 7

lipoglycopeptide - the same as vancomycin, but has a lipophilic side chain that allows for enhanced binding

Question 8

Telavancin

Answer 8

disrupts the cell membrane depolarization - also a lipoglycopeptide. Depolarization is due to lipophilic side chain

Question 9

Oritavancin

Answer 9

also a lipoglycopeptide - increases membrane permeability - can dimerize and anchor to the cell membrane, can also inhibit bacterial RNA synthesis, has an affinity for binding with D-ala-D-lactate, so effective for bacteria with vancomycin resistance