Module 4 Flashcards
Antimicrobial Drugs
Salvarsan
used to treat syphilis (STD)
A synthesised compound derived from arsenic (toxic) to be less toxic to humans whilst still having the antimicrobial properties
Lead to the discovery of Chemotherapy
What is Antibiotics
Chemical compound that is produced by a microorganism that in small amounts can kill/inhibit another microorganism
Selective Toxicity
The ability of an antimicrobial agent to inactivate or destroy an microorganism without harming the host cells
It’s easy to find chemical compounds that can kill the pathogen, however, it is hard to find one’s that don’t harm the host
How to Find a Suitable Drug
Find a reaction/structure that is unique to the target microorganism that does not harm the host cells
The drug must be able to alter/damage the microorganisms in a way to prevent replication or to cause cell death
Narrow and Broad Spectrum Drug
Narrow spectrum drugs only work on a select few types of microorganisms
Broad spectrum drugs works against several types of microorganisms
Cidal and Static (antimicrobial type)
Cidal, kills the microbe by causing irreversible damage
Static, inhibits replication without killing
4 Target sites for Bacterial action (antibiotics)
Bacterial Cell wall synthesis
Protein Synthesis
Nucleic Acid Synthesis
Cell membrane
Targeting Bacterial Cell wall synthesis
Peptidoglycan is unique in bacterium, hence it is a good area for selective attack of antimicrobials
(Interfering with the synthesis of peptidoglycan
Penicillin is the most important
(belongs in a group known as Beta-Lactam)
(4-member Lactam ring is found in this group)
Resistant Bacteria consist of Beta-Lactamse, which breaks open the Beta-Lactam ring, allowing for the antimicrobial to be destroyed
Targeting Bacterial Protein Synthesis
Aminoglycosides
Interferes with the translation of the mRNA into protein
(Bacteriocidal)
Causes misreading of mRNA, leading to substitution of the wrong amino acids into the peptide chain
Tetracyclines
(Broad Spectrum)
(Bacteriostatic)
Prevents the attachment of amino acids to the ribosome
Targeting Nucleic Acid Synthesis
inhibits the synthesis of nucleotide precursors or by inhibiting DNA/RNA replication
Targeting the Function of Cell Membrane
Disrupts the phospholipid bilayer of the membrane
Antiviral Drugs
Drugs that inhibit viral enzymes also inhibit host cell enzyme, hence side effects are common
Most are Virostastic (Not virocidal)
Must target unique part in the cycle of viral replication
GO back and look at the variety of microorganisms and their mode of action
YIKES
