Cell wall inhibitors 2.1

Question 1

MOA of Bacitracin

ADR of Bactiracin

Answer 1

MOA: inhibits bactoprenol phosphatase

ADR: Nephrotoxicity

Question 2

MOA of cycloserine

Use of cycloserine

Answer 2

MOA: inhibits alanine racemase (L-ala –> D-ala)

Use: Anti-tubercular

Question 3

MOA of Fosfomycin

Use of Fosfomycin

Answer 3

MOA: inhibits enolpyruvate transferase and blocks the addition of phosphoenolpyruvate to UDP-NAG

Use: UTI #barah

Question 4

MOA of polymixin B

Answer 4

destabilizes gram negative bacteria outer cell wall through ionic interactions

Question 5

MOA of gramicidin

Answer 5

allows uncontrolled ion transport (K+/Na+) across plasma membrane
Destroys ionic gradient

Question 6

Which Beta lactam antibiotic has no cross allergy w/ penicillin

Answer 6

Aztreonam

Question 7

MOA vancomycin

Answer 7

inhibits tranglycosylase (MG-MG link), inhibits transpeptidation

Question 8

MOA of penicillins

Answer 8

target the transpeptidase (PBP) –> prevent crosslinking of pentapeptide and peptidoglycan = weakening of cell wall

Bactericidal

Question 9

List classic penicillins (4)

What enzyme are they highly sensitive to?

Answer 9

Penicillin G
Benzathine penicillin G
Procaine penicillin G
Penicillin V (oral penicillin G)

Sensitive to lactamases (penicllinases)

Question 10

What bacteria are classic penicillins mainly used against? (4 groups)

Answer 10

Gram positive cocci and rods (Staphylococcus and Streptococcus)

Anaerobic bacteria (Clostridium, Actinomyces )

Syphilis (Treponema pallidum)

Gram negative cocci (N. Meningitidis)

Question 11

Which bacteria are the first choice when using penicillin G? (4)

Answer 11

Syphilis (Treponema Pallidum)

Gas gangrene (Clostridial perfringens)

Rheumatic fever prophylaxis (Streptococcus pyogene).
Penicillin benzathine once a month (life long, debatable- minimum 5 years or till 21 years age)

Listeria (Listeria monocytogenes) (ampicillin is equally effective, more often used)