AM - Antibiotic Action Lecture 1 Flashcards
What are the 3 ways antibiotics act?
- Inhibiting Cell Wall Synthesis
- Inhibiting Protein Synthesis
- Inhibiting Nucleic Acid Synthesis
example of antibiotics that inhibit cell wall synthesis?
Penicillins, Cephalosporins & Glycopeptides
Example of antibiotics that inhibit protein synthesis?
Aminoglycosides (Gentamicin) Macrolides (e.g. Erythromicin) Tetracycline Oxazolidinones (Linezolid) Cyclic Lipopeptides (Daptomycin)
Example of antibiotics that inhibit nucleic acid synthesis?
Quinolones
E.g. Ciprofloxacin & Nalidixic acid
Why dont cell wall synthesis inhibitors affect human cells?
Because they lack cell walls
How do B-lactams work?
- Bind to PBPs
- Inhibits carb chain cross-linking
- Peptidoglycans can’t be formed
- Autolytic enzymes kill the cell
What are PBPs?
Penicillin Binding Proteins
Enzymes that synthesize cell wall
What was the first antibiotic discovered?
Penicillin G [Benzyl Penicillin]
Why are many gram -ve bacteria resistant to Benzyl Penicillin?
Gram -ve bacteria have a relatively impermeable cell wall.
How are cephalosporins generally grouped?
By Generations (usually chronological)
How do Glycopeptides inhibit cell wall synthesis?
Inhibits assembly of peptidoglycan precursors
On what bacteria do glycopeptides act?
Glycopeptides act on Gram +ve bacteria
Examples of Glycopeptides?
Vancomycin & Teicoplanin
Why are glycopeptides delivered parenterally?
Theyre not absorbed in the gut
Whats the dosage regime for Teicoplanin?
Once daily