Chemotherapies Flashcards
How does resistance to Vancomycin occur?
When one of the D-Alanines in the bacterial cell wall is switched to D-lactic acid in which one of the amides is switched to an ester. Normally Vancomycin interacts with the cell wall via four Hydrogen bond interactions, when switched to an ester it loses that interaction making the drug ineffective.
How do aminoglycosides work?
They work by binding to the 30S ribosomal unit (not present in eukaryotes). This prevents the movement of the ribosome across the mRNA and means that it cannot be read.
What is the effect of blocking translation?
mRNA cannot be read and shortened or the incorrect proteins are synthesised. This increases the cell wall permeability and increased drug uptake.
How do Tetracyclines work?
They prevent translation by binding to the ribosome and preventing the t-RNA unit from binding which prevents further amino acids from binding and also prevents the protein from being released.
Which other types of antibacterials can chloramphenicol not be used in combination with?
Macrolides as they both work by the same mechanism: both bind to the A-site of the 50S ribosomal unit which inhibits the movement of the ribosomes across the mRNA.
What are some examples of macrolides?
Erthromycin and Azithromycin
What are some of the methods of reducing antibiotic resistance?
Using combination therapies, two different antibiotics acting at two different biological targets.
Ensure that the course of antibiotics is completed.
Using novel biological targets
Using broad spectrum first and then narrow spectrum
Understanding the mechanistic intimacies of the drug action
Which drug is the last resort in treating Staphyloccus aureus infections?
Vancomycin
How do sulfonamides work?
They act against the cell wall metabolism (anti-metabolites).
Where does Non-nucleoside reverse transcriptase act?
Allosteric binding site
What are some examples of Non-nucleoside reverse transcriptase inhibitors?
Nevirapine and Delavirdine
