Antibiotics (Bailey) Flashcards
What is the difference between bactericidal agents and bacteriostatic agents?
Bactericidal: KILL bacteria
Bacteriostatic: INHIBIT growth
What antibiotics affect the cell wall?
Penicillins and beta-lactams
What are the five ways antibiotics can function?
- Inhibit cell wall
- Disrupt cell membrane
- Inhibit protein synthesis (attack ribosome)
- Inhibit nucleic acid synthesis
- Antimetabloites
What is the 30s subunit of bacterial ribosomes responsible for?
Translation of mRNA
What is the 50s subunit responsible for?
Joining amino acids together and moving the complex along the mRNA
T/F: Antibiotics can only block the 30s subunit of bacterial ribosomes.
FALSE
They can inhibit either 30s or 50s and can effect many aspects of the ribosome process
How do sulfonamides and trimethoprim function?
Inhibit folic acid metabolism
How does metronidazole function?
Inhibits DNA synthesis
How do aminoglycosides (streptomycin, kanamycin, etc.), tetracyclines, and erythromycin function?
Inhibit ribosome function and protein synthesis
What are the three steps in the action of antibiotics?
- Drug penetrates the envelope
- Transport into the cell
- Drug binds to target
What are the three mechanisms of drug resistance?
- Synthesis of enzymes that inactivate the drug
- Prevention of access to target site by inhibiting uptake or increasing secretion of the drug
- Modify target site
How does penicillin disrupt the cell wall?
Competes for D-ala causing less mirroring strands of peptidoglycan to be formed -> less peptidoglycan -> weakened cell wall
How do bacteria spread antibiotic resistance from one to another?
Plasmids are transferred from one to another
What do sulfonamides inhibit the production of?
Folate
What is a therapeutic index?
Ratio between toxic and effective dose
