Antibiotics and antifungals Flashcards
What are drugs that target proteinsyhthesis particularly useful for targeting and why?
Gram negative bacteria as no peptidoglycan hinderance
Recall the pathway of nucleic acid synthesis and the enzymes involved
PABA–> DHOp (DHOp synthase)
DHOp –> DHF
DHF –> THF (DNA reductase)
Recall examples of drugs that inhibit nucleic acid synthesis and their targets
Sulphonamides: DHOp synthase
Trimethoprim: DNA reductase
Name the combination drug commonly used in inhibition of bacterial ucleic acid synthesis and what drugs it is made up of
Co-trimoxazole
= sulphonamides + trimethoprim
Describe the process of bacterial DNA replication that can be inhibited by antibiotics and the enzymes involved
Tension released from DNA molecule so that it can be replicated
Enzymes: topoisomerase IV and DNA gyrase
Recall the names of the antibiotic drugs that target bacterial DNA replication and their targets
Quinolones and fluoroquinolones
Target DNA gyrase and topoisomerase iv
Recall the name of a drug that inhibits RNA synthesis in bacteria
Rifamycins
How do bacterial and eukaryotic ribosomes differ?
Eukaryotes: 40s and 60s subunits
Prokaryotes: 30s and 50s subunits
Recall 4 classes of antibiotics capable of inhibiting protein translation
Aminoglycosides
Chloramphenicol
Macrolides
Tetracylcines
Give an example of an aminoglycoside antibiotic
Gentamycin
Give an example of a macrolide antibiotic
Erythromycin
Recall the components of peptidoglycan
N-acetyl muramic acid, N-acetyl glucosamine, pentapeptide
What class of antibiotic is capable of inhibiting peptidoglycan synthesis? Give an example with its MOA
Glycopeptides
eg Vancomycin
Binds pentapeptide to prevent synthesis
Recall the fate of a peptidoglycan molecule following synthesis
Transported across membrane by bactoprenol
Incorporated by PtG cross-links by transpeptidase
Recall which antibiotic is capable of inhibiting trasnportation of PtG into the cell wall and its MOA
Bacitracin
Inhibits bactoprenol
Recall the class of drugs capable of inhibiting peptidoglycan incorporation into the cell wall, and name examples
Beta-lactams:
Carbapenems
Cephalosporins
Penicillins
Recall 2 classes of drug that interfere with cell stability, and their general MOA
Lipopeptides: disrupt G+ cell walls
Polymyxins: bind to LPS to disrupt G- membranes
How do beta-lactamases destroy beta-lactam?
Hydrolyse the CN bond
Recall 2 mechanisms by which a drug may become beta-lactam resistance
- Production of beta-lactamase
2. Steric hinderence by production of molecules around beta-lactam ring
What is amoxicillin co-administered with, and why?
Clavulanic acid
Conveys resistance to beta-lactamase
Recall a bacteria that is resistant to trimethoprim, the mechanism by which it conveys resistance and which 2 general mechanisms of resistance this fulfils
E Coli
Can produce DHF reductase
= additional target and hyperproduction
Recall a bacteria that is resistant to quinolones, and why
S aureus
Mutations in ParC region of topoisomerase iv
Recall 5 mechanisms by which a bacteria may become antibiotic resistant
- Production of destruction enzymes
- Additional target
- Alteration in target enzymes
- Hyperproduction
- Alteration in drug permeation
Recall how a bacterium may alter antibiotic permeation to convey resistance
Reduce AQP expression
Increase efflux systems
