Antibacterial Drugs Flashcards
What is the difference between Narrow Spectrum and Broad Spectrum Antimicrobial?
Narrow Spectrum: Effective against a limited number of bacterial genera
Broad Spectrum: Effective against a large number of bacteria genera
Give two classes of antibiotics which target cell wall synthesis
- Beta lactams
- Glycopeptides
Describe the mechanism of action for Beta lactam antibiotics
Beta lactams are analogues to D-Ala-D-Ala, the terminal residues of NAM-NAG subunits, which are required for the final transpeptidation step performed by PBPs. Beta-lactams bind to PBPs which otherwise complete this step, hence wall synthesis is inhibited
State two subclasses of Beta-lactam antibiotics
Pencillins
Cephalosporins
Describe the mechanism of Glycopeptides
They bind to cell wall sub-units and prevent incorporation of a new unit
Give an example of a Glycopeptide
Vancomycin
Glycopeptides are only selective against one class of bacteria - which one?
Gram+
What are the differences in Ribosomes between Eukaryotes and Prokaryotes?
Eukaroyes - 80s (60s + 40s)
Bacteria - 70s (50s + 30s)
Give 2 examples of 30s Inhibitor Antibiotics
Aminoglycosides
Tetracyclines
Give 3 examples of 50s Inhibitor Antibiotics
Chloramphenicol
Erythromycin
Clindamycin
What are the three ways we can target Bacterial Protein Synthesis
- Target ribosomes
- Target tRNA inhibitor
- Target EF-G elongation factor
Give 1 example of EF-G elongation factor inhibitors
Fusidic acid
Of the 30s ribosome subunit inhibitors, which are bactericidal and which are bacteriostatic?
Aminoglycosides - Bactericidal
Tetracyclines - Bacteriostatic
Give 1 example of an Aminoglycoside drug
Gentamycin
Give two classes of drugs which inhibit bacterial Nucleic acid synthesis. What do they inhibit?
- Quinolones - DNA inhibition
2. Rifamycins - mRNA inhibition
What is the mechanism of action for Rifampicin?
Rifampicin is a type of Rifamycin, hence it blocks RNA nucleic acid synthesis. Blocks DNA-dependent RNA polymerase
Give 1 example of a Quinolone drug
Ciprofloxacin
Give two classes of drugs which inhibit bacterial metabolic pathways
Sulfonamides
Trimethoprim
What 1 class of drugs affect bacterial cytoplasmic membranes?
Polymyxins
Give one example of Polymyxins
Colistin
How do we classify antibiotic resistance?
What is it based on?
Three stages:
- Sensitive
- Intermediate
- Resistant
Based on Minimum Inhibitory Concentration
What is MIC with respect to antibacterial agents?
Minimum concentration of the antibacterial agent required for bacterial growth to be inhibited
Give 4 examples of ways bacteria have developed resistance to antibiotics
Beta-lactamase
Acquisition of mutations
Plasmids
Increase of efflux pumps
What MDR-TB?
Multidrug resistant TB
TB which is resistance to atleast 2 first-line TB drugs (Isoniazid + Rifampicin)
