Antibiotics I Flashcards
1
Q
What are the three main principles surrounding antimicrobial therapy?
A
- Take advantage of physiological differences between species
- Antimicrobial should selectively injure or kill an invading microorganism without harming host cells (SELECTIVE TOXICITY)
2
Q
What would be the characteristics of an ideal antibiotic?
A
- Selective target
- Bactericidal
- Narrow spectrum
- High therapeutic index
- Few adverse reactions – toxicity, allergy
- Various routes of administration (IV IM, SC, oral)
- Good absorption and distribution to the site of infection
3
Q
What should cell wall inhibitor antibiotics have to be maximally effective?
A
- Actively proliferating organisms
- Have little effect on bacteria not growing or dividing
4
Q
Give examples of beta-lactams.
A
- Penicillin and penicillin derivates
- Carbapanems
- Cephalosporins
5
Q
Beta-lactams can vary depending on the R group side chain.
What effects can this have?
A
- Affects antimicrobial spectrum, stability in stomach acid and susceptibility to beta-lactamases
6
Q
What is the general mechanism of action for penicillin and cephalosporins?
A
- Inactivate penicillin binding proteins
- Interfere with transpeptidation - cause cell lysis so bactericidal
- Production of autolysins
7
Q
Describe the mechanism of action of glycopeptides e.g vancomycin.
A
- Inhibits bacterial cell wall synthesis by binding to the D-Ala-D-Ala peptide motif of the peptidoglycan precursor
- Disrupts the transglycosylation activity of the cell wall synthesis process.
- Forms incomplete and corrupted cell wall, which makes the replicating bacteria vulnerable to external forces such as osmotic pressure
8
Q
Describe different ways in which antibiotic resistance can occur.
A
- Decreased uptake
- Alterations to target proteins/enzymes
- Inactivating enzymes
- Efflux of drug by pumps
9
Q
**Describe the clinical indications of carbapanems with examples. **
A
