Antibitoics Flashcards
Define antibacterial drugs?
Compounds that show selective toxicity against bacterial cells vs. mammalian cells and can be used in patients.
What is selective toxicity?
The central concept of antibacterial drug action to minimise the damage to the host during treatment based on exploiting the differences in the structure or biochemistry of the infecting agent and host.
What are recurring themes in antibacterial mechanisms of action?
Substrate analogues, steric hindrance, enzyme inactivation, disruption or subversion.
What are the targets of antibacterial agents?
Cell wall, membrane, nucleotide metabolism, DNA, transcription and protein synthesis.
Give an example of an antibacterial drug that targets the cell wall?
Beta-lactams: penicillin/ methicillin
Glycopeptides: vancomycin.
Give an example of an antibacterial drug that targets the membrane?
Daptomycin: it interacts, integrates, aggregates and depolarises the membrane causing leakage of contents and death.
Give an example of an antibacterial drug that targets nucleotide metabolism?
Sulfamethoxazole or trimethoprim.
Sulfameynoxazole is a competitive inhibitor of DHPS and trimethoprim inhibits dihydrofolate reductase. Together they can work together as co-trimoxazole.
Give an example of an antibacterial drug that targets DNA?
Quinolones/fluoroquinolons: target gyrase and Topoisomerase 4
Give an example of an antibacterial drug that targets transcription?
Rifampicin, binds the beta subunit of prokaryotic RNA polymerase.
Give an example of an antibacterial drug that targets protein synthesis?
Large number, most act directly on either the large or small ribosomal subunit and are bacteriostatic.
Linezolid, an oxazolidinone which binds the 50s subunit and blocks amino acid residue in the A site from binding.
Define an antibiotic?
A natural substance produced by one micro-organism that kills or inhibits the growth of another. Produced as secondary metabolites by bacteria and fungi.
