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
beta lactam antibiotic that treats infections caused by gram-positive organisms and gram-negative cocci, and non beta lactamase producing anaerobes
natural penicillins
what are natural penicillins susceptible to
beta lactamase (penicilloic acid)
natural penicilins (PEPEBEBEPRO)
Penicillin G / benzylpenicillin (IV)
Benzathine penicillin G (IM)
Procaine penicillin G (IM)
Penicilin V / phenoxymethylpenicillin (PO)
resistant to beta lactamase and is for staphylococci and streptococci
resistant to beta lactamase resistant / anti-staphylococcal penicillin
b-lactamase penicillins (MNIOCD)
Methicilin
Nafcillin
Isoxazolyl penicillin
Oxacillin
Cloxacillin
Dicloxacillin
susceptible to b-lactamase and are more effective against gram negative bacteria
extended-spectrum penicilins
spectrum of natural penicilins
aminopenicillins
what are diseases treated by aminopenicillins?
Haemophilus influenzae
Escherichia coli
Proteus mirabilis (commonly administered with b lactamase inhibitors)
prototype: superior to other penicillins
ampicilin
what diseases does ampicillin usually treat?
Listeria monocytogenes and enterococci
most active among b-lactams for Streptococcus pneumoniae
Amoxicillin
list antipseudomonal penicillins
Carboxypenicillins
Carbenicillin
Ticarcillin
antipseudomonal penicillin that has less gram positive activity and is active against Pseudomonas, Enterobacter, and Proteus spp.
Carboxypenicillin
less gram positive activity and is used to treat Pseudomonas, Klebsiella, and certain other gram negative organisms
ureidopenicillins
same activity with ampicillin and is for Listeria and Enterococci
piperacillin
list piperacillin
Mezlocillin
Azlocillin
