effects of antibiotics- Bailey Flashcards
what are the 2 main modes of action in antibiotics?
Bactericidal
Bacteriostatic
characteristics of a “perfect antibiotic”
-Broad spectrum of activity
-Would not induce resistance
-High Therapeutic Index
—-Ratio between toxic dose and effective dose
If ratio is 1, then you need a toxic dose in order to eradicate the microbe.
-Selective toxicity
name the 5 ways that antibiotics inhibit bacteria
1) inhibit cell wall synthesis
2) disruption of cell membrane function
3) inhibit protein synthesis
4) inhibit nucleic acid synthesis
5) act as anti-metabolites
how does penicillin inhibit cell wall synthesis?
attacks the formation of the cell wall at D-alanine
how does Polymyxin B sulfate work?
A) Disruption of Cell Membrane Function
B) Disrupts cell membrane- Binds to phospholipids
which antibiotics affect DNA gyrase?
Nalidixic acid
Quinolones
which antibiotics inhibit RNA polymerase
rifamycin
which antibiotics are used to treat odontogenic infections?
1) Penicillin
2) Cephalosporins
3) Clindamycin (bone)
which medications are used to treat periodontitis?
Tetracyclines and Metronidazole
name the steps of action of antibiotics
- Drug penetrates the envelope
- Transport into the cell
- Drug binds to target
mechanisms of drug resistance
A) Synthesis of enzymes that inactivate the drug
B) Prevention of access to the target site
1. Inhibiting uptake 2. Increasing secretion of the drug
C) Modification of the target site
what drug(s) does β-lactamases inactivate?
Penicillin, Cephalosporin
how do many antibiotics enter the cell?
porins
proteins that extend across the lipid bilayer and create channels or pores
how do bacteria defend themselves against antibiotics that enter thru porins?
drug efflux transporters
how do bacteria modify the target site of antibiotics?
Modify enzyme affinity
Alteration of Metabolic Pathway
