Antibiotics Flashcards
1
Q
How does bleach disinfects
A
- Broad spectrum
- Chlorine denatures proteins
2
Q
How does antibiotics work
A
- affect targets found in bacterial cells and not in mammalian eukaryotic cells
- Becoming concentrated in the bacterial cell and not in the host cell
3
Q
What does Bactericidal mean
A
- Bacteria are killed
4
Q
What does Bacteriostatic mean
A
- Bacteria are inhibited: host defences usually take over
5
Q
What targets the cell wall?
A
- Beta-lactams
- Vancomycin
- Isoniazid
- Polymyxin
- Daptomycin
6
Q
What does NAM stand for and what is it made out of
A
- N-acetylmuramic acid
- Made up of NAG + lactic acid and 3 amino acids
7
Q
What does NAG stand for ?
A
- N-acetylglucosamine
8
Q
What is NAM and NAG linked by
A
- peptide bridges
8
Q
What is Peptidoglycan
A
- mesh-like polymer that forms the main structural component of most bacterial cell walls
9
Q
What are the mechanisms of action of glycopeptides
A
- Normal cell wall ->
- Transpeptidase enzymes bind NAM-NAG monomers ->
- Vancomycin binds NAM-NAG monomers: TP inhibited ->
- Autolysins break peptide bonds but no further bonds are created
10
Q
What is included in Glycopeptide antibiotics
A
- vancomycin and teicoplanin
11
Q
what does glycopeptides do to prevent transglycosylation
A
- bind to the growing peptidoglycan chain and prevent transglycosylation
12
Q
Which antibiotic is known to be last resort
A
- vancomycin
13
Q
How does penicillin work
A
- penicillin (and all beta-lactams) bind to penicillin-binding proteins (PBPs) in the growing cell wall
- cross links between peptidoglycan chains are inhibited and cell lysis results
14
Q
what are the different classes of beta-lactams
A
- ampicillin
- methicillin
- carbenicillin
- oxacillin
15
Q
What are Beta-lactamase inhibitors
A
- have a lactam ring, but are weak antibiotics
16
Q
How does beta lactamase inhibitors become effective
A
- beta-lactamase must have a higher affinity for inhibitors than drug
- inhibitor must bind irreversibly to beta-lactamase
17
Q
what is the mechanism of action of polymyxins
A
- disrupts inner and outer cell membranes, causing cell lysis
- acts gram-negatives only
- polymyxin B; polymyxin E
18
Q
What are Aminoglycosides
A
- binding and distortion of ribosome - perturbation of translocation prevents protein synthesis initiation
19
Q
A
