Mechanisms of Action and Inhibitors of Cell Wall Synthesis Flashcards
mechanisms of action of antimicrobial drugs
- Inhibition of cell wall synthesis
- Inhibition of cell membrane function
- Inhibition of protein synthesis (ie, inhibition of translation and transcription of genetic material)
- Inhibition of nucleic acid synthesis
- Autonomous / Indifferent
- Antagonistic 1 + 1 = 0
- Additive 1 + 1 + 2
- Synergistic 1 + 1 = 3 or 1 + 1 > 2
- Potentiation 0 + 1 > 1
The result of 2 drugs is equal to the result of the most effective drug by itself
autonomous / indifferent
➢ eg. Antidotes
➢ static + cidal
➢ Doxycycline (stop/inh growth) + Amoxicillin (effective against actively dividing cells)
antagonistic 1 + 1 = 0
➢ cidal + cidal
➢ except penicillins + aminoglycosides → synergism
additive 1 + 1 + 2
➢ static + static = cidal
➢ tetracycline + chloramphenicol
➢ cotrimoxazole – trimethoprim + sulfamethoxazole
synergistic 1 + 1 = 3 or 1 + 1 > 2
➢ β-lactamase inh + antibiotic
➢ clavulanic acid + amoxicillin = co-amoxiclav
➢ sulbactam + ampicillin
➢ tazobactam + piperacillin
potentiation 0 + 1 > 1
binds to a variety of receptors in the bacterial cell membrane and cell all
β-LACTAM ANTIBIOTICS
what are the receptors that beta lactam antibiotics bind to called?
penicillin-binding proteins (PBPs)
how do beta lactam antibiotics act
by inhibiting transpeptidases, the enzymes that catalyze the final cross-linking step in the synthesis of peptidoglycan
autolytic enzymes that are activated in the penicillin treated cells and degrade the peptidoglycan
murein hydrolases
what is beta lactam antibiotics effective for
both gram-negative and gram-positive bacteria
ti what microorganisms is beta lactam antibiotics ineffective with
- cell wall-less microorganisms
- acid fast bacterium
- intracellular parasites
- resistant microorganisms
adverse effect of beta lactam antibiotic where the immune system causes you to go into shock and and prevent you from breathing and the likes
allergic or anaphylactic reaction
adverse effect of beta lactam antibiotics where sensitivity to one substance that renders an individual sensitive to other substances of similar chemical structure.
cross-sensitivity reaction
adverse reaction of beta lactam antibiotics which is a short-term (from days to a few weeks) detoxification reaction in the body
jarisch-herxheimer reaction
