Lecture 2.2 - Antimicrobials Flashcards
Give a brief description of how antibiotics targeting bacterial wall synthesis work
Inhibit transpeptidase, preventing cross-linking of peptidoglycan in the cell wall - hence causes lysis
Give 2 examples of types of antibiotic which target bacterial wall synthesis
B-lactams
Glycopeptides
Give a brief outline of how antibiotics that target bacterial protein synthesis work
Bind to the 50S subunit of the bacterial ribosome, competing with tRNA at the A site - hence prevent translocation
Give 3 examples of antibiotics which target bacterial protein synthesis
Macrolides, tetracyclines and aminoglycosides
What do antibiotics bind to which target bacterial nucleic acid synthesis?
What does this prevent?
RNA polymerase
Prevents transcription
Give an example of a type of antibiotic which targets bacterial nucleic acid synthesis
Quinolones
Give 4 examples of antimicrobial resistance mechanisms
- Bacteria produce and secrete drug-inactivating enzymes
- Bacterial enzyme targeted by drug has lowered affinity for drug and hence harder for drug to bind
- Decreased membrane permeability to drug
- Increased efflux of drug as clearance proteins up-regulated
By what two mechanisms is resistance passed on?
Natural selection, where the antibiotic is the selection pressure
Horizontal transfer
Explain horizontal gene transfer
Section of chromosome or plasmid passed on via either:
- conjugation
- transduction
- transformation
How is antibiotic activity measured?
Minimum inhibitory concentration and disc sensitivity testing
What is the mechanism of B-lactams?
What other type of antibiotics work this way?
Inhibit bacterial cell wall synthesis
Glycopeptides
Give some examples of B-lactam classes
Penicillins
Cephalosporins
Carbapenems
Give an example of a glycopeptide antibiotic
Vancomycin
What is the mechanism of tetracylines?
Which other antibiotics work in this way?
Inhibit bacterial protein synthesis
Aminoglycosides and macrolides
Give an example of an aminoglycoside
Gentamicin
