Cell Wall Synthesis Inhibitors

Question 1

Betalactam Antibiotics

Answer 1

Penicillin

Question 2

Penicillin MOA

Answer 2

Penicillins are bactericidal

Bind to penicillin-binding proteins and inactivate transpeptidase,

which prevents the cross linking of peptidoglycan chains in the bacterial cell wall,

leading to loss of cell rigidity and cell death.

Question 3

Penicillin Mechanism of Resistance (MOR)

Answer 3

Penicillinases (b-lactamases) break the betalactam ring: Staphylococci

Alteration of penicillin-binding proteins: Staph. Aureus: MRSA, penicillin resistant pneumococci

Reduced permeability in Gram-negative cell membranes (change in porin structure): Pseudomonas

Question 4

Bactericidal antibiotics:

a) How do they work?
b) examples

Answer 4

a) Cause death of the microorganism
b)
• Penicillins
• Aminoglycosides
• Cephalosporins

Question 5

Bacteriostatic antibiotics:

a) What do they do?
b) examples

Answer 5

a) Inhibits the growth of the microorganism

b)
• Sulfonamides,
• Tetracyclines
• Erythromycin

Question 6

Antimicrobials that inhibit cell wall synthesis

Answer 6

• Penicillins
• Cephalosporins
• carbapenems
• monobactum
• Vancomycin

Question 7

Antimicrobials that Inhibit bacterial protein Synthesis

Answer 7

• Tetracyclines
• macrolides
• Chloramphenicol
• Aminoglycosides
• streptogramins
• linezolid

Question 8

Antimicrobials that inhibit nucleic acid synthesis

Answer 8

• Fluroquinolones

* rifampin

Question 9

Which drug has this MOA:

Bind to penicillin-binding proteins and inactivate transpeptidase,

which prevents the cross linking of peptidoglycan chains in the bacterial cell wall,

leading to loss of cell rigidity and cell death.

Answer 9

Penicillin

Question 10

Staphylococci MOA

Answer 10

Penicillinases (b-lactamases) break the betalactam ring

Question 11

Feature of Gram + wall

Answer 11

• teichoic acid (causes endotoxic shock)

* thick peptidoglycan layer and no outer membrane.

Question 12

Features of Gram - cell wall

Answer 12

• outer membrane,
• then peptidoglycan layer
• LPS (causes endotoxic shock)

Question 13

Which drugs have this MOR:

Alteration of penicillin-binding proteins

Answer 13

• Staph. Aureus: MRSA,

* penicillin resistant pneumococci

Question 14

Which drug has this MOR?

Reduced permeability in Gram-negative cell membranes

Answer 14

Pseudomonas

Question 15

Narrow spectrum Penicillins

Answer 15

• penicillinase susceptible = Penicillin G (parenteral)
• Penicillin V (oral)

• Used against Streptococci, pneumococci, meningococci (only gram – cocci that responds to penicillin), treponema pallidum

Question 16

how are penicillin V and Penicillin G given?

Answer 16

• Penicillin G = parenteral

* Penicillin V (oral)

Question 17

Pseudomonas MOA

Answer 17

Reduced permeability in Gram-negative cell membranes (change in porin structure)