Use of Antibiotics Flashcards
What is the primary function of antibiotics?
Inhibit bacterial growth
How do antibiotics target only bacterial cells?
They interfere with specific bacterial enzymes and not eukaryotic ones. (specificity)
What are the main cell wall synthesis antibiotics?
Beca lactams, Vancomycin, Bacitracin, Cell membrane
What is the mechanism of action for β-lactams?
Inhibit last step in peptidoglycan synthesis. Prevents cross linking via transpeptidases.
What is the peptidoglycan layer?
It is barrier made up of sugar chains (glycan strands) cross-linked by peptide bridges, giving it strength, rigidity and flexibility.
What are the classes of β-lactams?
- Penicillin
- Cephalosporin
- Carbapenem
- Monobactam
What is the common allergy associated with β-lactams?
Most commonly to penicillins
What is the cross-reactivity percentage of penicillin allergy with cephalosporins?
~2.5%
What is the spectrum of glycopeptides?
Gram positive only
What is the mechanism of action for glycopeptides?
Bind to D-alanine-D-alanine portion of muramylpentapeptide. Inhibiting cross-linking
What is the spectrum of polymyxins?
Gram negative only
What is the mechanism of action for daptomycin?
Binds to phosphatidylglycerol in cell membrane
What do protein synthesis inhibitors target?
16S or 23S rRNAs in the ribosome functional sites
What are the categories of antibiotics that target folate synthesis?
- Sulphonamides
- Trimethoprim
What do fluoroquinolones inhibit?
Type II topoisomerases (DNA gyrase, topoisomerase IV)
What does rifampicin inhibit?
RNA synthesis
What is the mechanism of action of metronidazole?
Makes breaks in DNA
What is the activation requirement for metronidazole?
Requires activation by reduction by ferredoxin or flavodoxin (only found in bacterial cells)
What is the first generation cephalosporin example?
Cefazolin
What is the third generation cephalosporin example with improved stability against β-lactamases?
Ceftriaxone
What are Enterococcus spp. and Listeria spp. resistant to?
Cephalosporins
True or False: Antibiotic resistance can develop during therapy.
True
What is the role of a healthcare professional regarding antimicrobials?
Be a good steward of antimicrobials
Fill in the blank: The mortality rate from bacterial infections decreased from 82% in 1941 to ______ in 2009.
21%
