How Antibiotics Work--the Mechanism of
Action
Aminoglycosides:
Inhibit protein synthesis by binding to a portion of the bacterial ribosome. Most of them are bacteriocidal (i.e.,
cause bacterial cell death).
Bacitracin: Inhibits
cell wall production by blocking the step in the process (recycling of the membrane lipid carrier) which is needed
to add on new cell wall subunits.
Beta-lactam antibiotics: A name for the group of antibiotics
which contain a specific chemical structure (i.e., a beta-lactam ring). This includes penicillins, cephalosporins,
carbapenems and monobactams.
Cephalosporins: Similar to penicillins in their mode of
action but they treat a broader range of bacterial infections. They have structural similarities to penicillins
and many people with allergies to penicillins also have allergic reactions to cephalosporins.
Chloramphenicol: Inhibits protein synthesis by binding to
a subunit of bacterial ribosomes (50S).
Glycopeptides
(e.g., vancomycin): Interferes with cell wall development by blocking the attachment of new cell wall subunits
(muramyl pentapeptides).
Macrolides
(e.g., erythromycin) and Lincosamides
(e.g., clindamycin): Inhibit protein synthesis by binding to a subunit of the bacterial ribosome (50S).
Penicillins:
Inhibits formation of the bacterial cell wall by blocking cross-linking of the cell wall structure. The cell wall
is a needed protective casing for the bacterial cell.
Quinolones:
Blocks DNA synthesis by inhibiting one of the enzymes (DNA gyrase) needed in this process.
Rifampin:
Inhibits RNA synthesis by inhibiting one of the enzymes (DNA-dependent RNA polymerase) needed in this process.
RNA is needed to make proteins.
Tetracyclines:
Inhibit protein synthesis by binding to the subunit of the bacterial ribosome (30S subunit).
Trimethoprim and
Sulfonamides: Blocks cell metabolism by inhibiting enzymes
which are needed in the biosynthesis of folic acid which is a necessary cell compound. |
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