ANTIBIOTIC DRUG CLASSES AND MECHANISM

Question 1

Give examples of antibiotics which inhibit protein synthesis

Answer 1

Chloramphenicol
Lincosamides
Macrolides
Amino glycosides
Pleuromutilin
Tetracyclines
Nitrofurans

Question 2

Give examples of antibiotics which inhibit cell membrane function

Answer 2

Polypeptides
Antimicrobial peptides

Question 3

Give examples of antibiotics that inhibit cell wall synthesis

Answer 3

B-lactam antibiotics
Vancomycin
Bacitracin

Question 4

Give examples of antibiotics that inhibit DNA dependent RNA polymerase

Answer 4

Rifampicins

Question 5

Give examples of antibiotics that disrupt DNA structure

Answer 5

Nitroimidazoles
Metronidazole

Question 6

How do antibiotics inhibit cell wall synthesis

Answer 6

Targets peptidoglycan (unique to bacteria)
Lysozyme produced by host breaks bonds in polysaccharide
Beta-lactam inhibits penicillin binding protein (transpeptidase) weakening cell wall => increased osmotic pressure => burst
Glycopeptides cap peptide chains to weaken cell wall => bursts

Question 7

Describe how Beta-lactam antibiotics work

Answer 7

Beta-lactam inhibits penicillin binding protein (transpeptidase) weakening cell wall => increased osmotic pressure => burst

Question 8

How do antibiotics inhibit protein synthesis

Answer 8

inhibit translation of RNA to proteins by binding to ribosomal complex

Question 9

How do aminoglycosides work?

Answer 9

Bacteriocidal
Inhibit protein synthesis by binding to 30S and effects a number of steps of protein synthesis leading to non-functional proteins
GRAM -VE

Question 10

How do tetracyclines work?

Answer 10

Bacteriostatic
Inhibit protein synthesis
Actively enter cell and bind to 30S subunit preventing tRNA attachment
GRAM -VE and +VE

Question 11

How does chloramphenicol work?

Answer 11

Bacteriostatic
Inhibits protein synthesis by binding to 50S subunit and preventing linkage of amino acids to growing peptides
Broad spectrum

Question 12

How do sulphonamides/trimethoprim (TMPS) work?

Answer 12

Affect DNA
Competitive inhibitors of dihydropteroate synthetase to inhibit dihydrofolate synthesis which is required for DNA synthesis

Question 13

How do Quinolones and Novobiocin work?

Answer 13

Affect DNA
Bind to and stops DNA Gyrase preventing packing of DNA, inhibits supercoiling of chromosome => disrupts associated processes

Question 14

How do Nitroimidazoles work?

Answer 14

Affect DNA
Reduction products are reactive with DNA causing DNA strands to break

Question 15

How does Rifampicin work?

Answer 15

~Inhibits DNA dependent RNA polymerase => blocks initiation of protein synthesis

Question 16

Describe the use of antimicrobial peptide

Answer 16

Topical application
Interact and disrupt membranes
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