Antimicrobial agents

Question 1

Antiobiotics

Answer 1

Naturally occuring microbial products

Question 2

Antimicrobials

Answer 2

Semi-synthetic and synthetic compounds (includes antiobiotics)

Question 3

Name the 4 sites of action for antimicobials:

Answer 3

1) cell wall
2) Protein synthesis
3) Nucleic acid synthesis
4) Cell membrane

Question 4

Name the 3 mechanisms of antimicrobial resistance

Answer 4

1) Drug inactivating enzymes
2) Altered target with lowered affinity for the antimicrobial
3) Altered uptake (decreased permability of the membrane or increased efflux)

Question 5

List the inhibitors of the cell wall synthesis

Answer 5

1) Beta-lactam agents
2) Glycopeptides
3) Fosfomycin
(the three big ones)

4) Bacitracin (too toxic for systemic use)
5) Iosniazid
6) Cycloserin

Question 6

Name the main beta lactam agents

Answer 6

1) Penicillin
2) Cephalosporins
These two are the most important

3) Carbapenem
4) Oxacephem
5) Monbactam
6) Clavam
7) Sulphones

Question 7

How to recognize a penicillin

Answer 7

Ends with cillin

Question 8

Difference between cephalosproin and penicillin

Answer 8

Penicillin = 4 carbon ring connect to 5 carbon ring
Cephalosporin = 4 carbon ring fused to 6 carbonring - cephalosporin can in principle be used agaiunst MRSA (although it is beta-lactam derived)

Question 9

Glycopeptides

Answer 9

Big (can’t penetrate outer membrane of gram negatives) - also anti cell wall. Often used on coccy that are multi resistant.

Question 10

Name main classes of protein synthesis inhibition

Answer 10

1) Tetracyclines
2) Chloramphenicol
3) Aminglycosides
4) Macrolides
(de vigtigste)

5) Lincosamides
6) Fusidic acid
7) Linezolid
8) Streptogramin
9) Mupirocin

Question 11

Tetracyclin

Answer 11

Broad spectrum - Inhibits tRNA binding

Question 12

Chloramphenicol

Answer 12

Broad - inhibits AA-chain elongation - sometimes fatal side effects

Question 13

Aminoglycosides

Answer 13

Inhibit formation of ribosomal complex

e.g. streptomycin

Question 14

Macrolides

Answer 14

Large lactone ring - act by interfering with translocation of AA-chains oin the ribosome.

Question 15

Lincosamides

Answer 15

Binds to 50 S ribosome

Question 16

Fusidic acid

Answer 16

Blocks factor G (peptide elongation)

Question 17

Linezolid

Answer 17

narrow gram positive -hinders ribosome initiation complex

Question 18

Mupirocin

Answer 18

Inhibits isoleucine incorporation.

Question 19

Name the classes of nucleic acid synthesis:

Answer 19

1) Sulphonamides and diaminopyrimidines
2) Quinolones
3) Nitroimidazoles
4) Nitrofurans
5) Rifamycins

Question 20

Sulphonamides mechanism

Answer 20

Important to reduce a vitamin necessary for thymidine synthesis. Broad spectrumbut lots of resistance.

Question 21

Quinolones mechanism

Answer 21

Acts on DNA gyrase - cannot unwind DNA

Question 22

Disruptions of cell membranes:

Answer 22

1) Polymyxins

2) Daptomycin

Question 23

What is a topical agent?

Answer 23

Drug that works by cleaning, mechanically altering the site of infection locally etc. - often used for funghi