Antimicrobials I Flashcards
Difference between antibiotics and chemotherapeutic agents
Antibiotics are naturally-occurringChemotherapeutic agents are synthetic
Goal of semi-synthetic drugs1)2)3)
1) Alter kinetics2) Reduce toxicity3) Broaden antimicrobial spectrum
When might it be useful for a drug to have a short half life?
If excreted by the kidneys, for a UTIIncreases the amount of antimicrobial in the urinary tract
Which type of bacterium is Bordatella?
Gram - rod
Bordatella intrinsic resistance
Intrinsically resistant to penicillin
Phases of bacterial growth curve1)2)3)
1) Lag phase2) Exponential phase3) Stationary phase
What qualifies an antimicrobial as bactericidal?
Kills 99.9% of bacteria3-log reduction (log10 scale)
When are bactericidal antimicrobials necessary?
In immunocompromised patients
Tetracycline structure
Four hexagonal carbon rings
Structural difference between penicillin and cephalosporin beta-lactams
Penicillin is a beta-lactam ring attached to a pentagonal structureCephalosporins are beta lactam ring attached to a hexagonal structure
Tetracycline pharmacokinetics
Very short half-lifeExcreted in bile
How are tetracyclines excreted?
In bile
Penicillin examples1)2)3)4)5)6)
1) Penicillin G2) Penicillin V3) Ampicillin4) Methicillin5) Flucloxacillin6) Carbenecillin
Penicillin G oral availability
Low
Penicillin V oral availability
Good
Organisms susceptible to penicillin G
Gram + rods, cocciGram - cocci