Antimicrobial Therapy Flashcards
What are the four sterile sites in the body?
Blood: Staph and Strep
CSF: Staph and Strep
Urine: Gram- enterics, Staph and strep
Lungs: S. pneumoniae
What are the 3 approaches to antibiotic therapy?
- Prophylaxis: Used to prevent infection
- Empiric: Used to treat suspected pathogen as you wait for culture results.
- Specific: Used to treat known pathogens.
What is the MIC?
MIC: Lowest concentration of drug that inhibits visible growth under standard conditions.
What is the MBC?
The lowest concentration of the antibiotic that kills 99.9% of the original inoculum
What is the Breakpoint MIC?
The concentration of antibiotic that can be achieved in the bloodstream with optimal therapy.
How do you interpret pathogen susceptibility to a drug?
Sensitive: MIC Breakpoint
Discuss Concentration-dependent killing
Peak levels determine the adequacy of treatment. The greater the AUC:MIC ratio, the greater the antibiotic effect.
Discuss Time-dependent killing
Drug level must achieve MIC at site of infection and be maintained to be effective; The longer the antibiotic concentration is greater than the MIC, the greater the effect.
Discuss the Post-antibiotic effect
Suppression of microbial growth after antibiotic concentration falls below MIC
What are the difficult sites to reach with antibiotics?
CSF, lungs, bone, heart and abscesses
What are the 3 characteristics of antibiotics that allows dosing to be the same?
- Good oral bioavailability
- Broad therapeutic window
- No adverse effects associated with peaks and troughs.
Which drugs inhibit Cell wall synthesis?
Beta-lactams;
Penicillins, Cephalosporins, Carbapenems, Monobactam, Vancomycin, Dalba/Tela/Oritavancin
Which drugs inhibit the plasma membrane?
Daptomycin
Which drugs inhibit 30S ribosome protein synthesis?
Aminoglycosides, Tetracyclines, Tigecycline
Which drugs inhibit 50S Ribosome protein synthesis?
Macrolides, Clindamycin, Line/Tedizolid, Quinopristin-dalfospristin.
