Antimicrobial agents Flashcards
Antiobiotics
Naturally occuring microbial products
Antimicrobials
Semi-synthetic and synthetic compounds (includes antiobiotics)
Name the 4 sites of action for antimicobials:
1) cell wall
2) Protein synthesis
3) Nucleic acid synthesis
4) Cell membrane
Name the 3 mechanisms of antimicrobial resistance
1) Drug inactivating enzymes
2) Altered target with lowered affinity for the antimicrobial
3) Altered uptake (decreased permability of the membrane or increased efflux)
List the inhibitors of the cell wall synthesis
1) Beta-lactam agents
2) Glycopeptides
3) Fosfomycin
(the three big ones)
4) Bacitracin (too toxic for systemic use)
5) Iosniazid
6) Cycloserin
Name the main beta lactam agents
1) Penicillin
2) Cephalosporins
These two are the most important
3) Carbapenem
4) Oxacephem
5) Monbactam
6) Clavam
7) Sulphones
How to recognize a penicillin
Ends with cillin
Difference between cephalosproin and penicillin
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)
Glycopeptides
Big (can’t penetrate outer membrane of gram negatives) - also anti cell wall. Often used on coccy that are multi resistant.
Name main classes of protein synthesis inhibition
1) Tetracyclines
2) Chloramphenicol
3) Aminglycosides
4) Macrolides
(de vigtigste)
5) Lincosamides
6) Fusidic acid
7) Linezolid
8) Streptogramin
9) Mupirocin
Tetracyclin
Broad spectrum - Inhibits tRNA binding
Chloramphenicol
Broad - inhibits AA-chain elongation - sometimes fatal side effects
Aminoglycosides
Inhibit formation of ribosomal complex
e.g. streptomycin
Macrolides
Large lactone ring - act by interfering with translocation of AA-chains oin the ribosome.
Lincosamides
Binds to 50 S ribosome
Fusidic acid
Blocks factor G (peptide elongation)
Linezolid
narrow gram positive -hinders ribosome initiation complex
Mupirocin
Inhibits isoleucine incorporation.
Name the classes of nucleic acid synthesis:
1) Sulphonamides and diaminopyrimidines
2) Quinolones
3) Nitroimidazoles
4) Nitrofurans
5) Rifamycins
Sulphonamides mechanism
Important to reduce a vitamin necessary for thymidine synthesis. Broad spectrumbut lots of resistance.
Quinolones mechanism
Acts on DNA gyrase - cannot unwind DNA
Disruptions of cell membranes:
1) Polymyxins
2) Daptomycin
What is a topical agent?
Drug that works by cleaning, mechanically altering the site of infection locally etc. - often used for funghi
