Barbarians at the Wall Flashcards
(33 cards)
What type of bacteria do extended spectrum antibiotics affect?
Affect gram positive and SOME gram negative bacteria
Bacteriostatic antibiotics work by…
Inhibiting a particular process, such as protein synthesis
What is a con of bacteriostatic antibiotics?
They have no affect on particular mechanisms, thus can be overcome.
How does a bacteriostatic antibiotic help to eliminate bacteria?
The immune system eliminates the drug once the antibiotic has suspended growth
Why is bacteriocidal preferred? (4 reasons)
- Reduces number, so makes it easier for host to kill ALL bacteria
- More rapid
- Irreversibly damages bacteria
- Complete killing occurs (good for endocarditis or immunocompromised patients)
What factors affect the choice of antibiotic? (3)
- specificity
- spectrum
- concentration of antibiotic at infection site
What factors affect the antibiotic reaching the desired site? (6)
- pH
- movement of drug across mem
- presence of pus
- presence of hemoglobin
- anaerobic conditions
- presence of foreign body
How does pus affect antibiotic administration?
Difficult for drug to penetrate pus
How does hemoglobin affect antibiotic usage?
**
How does a foreign body affect antibiotic usage?
**
What are some “host factors” that must be considered when giving a patient antibiotics? (5)
Host defense mechanisms Age Renal/liver Pregnancy/nursing Blood perfusion
What is the appropriate treatment for mixed bacterial infections?
Combination of effective agents
What is the appropriate treatment for severe/unknown infections?
Use a broad spectrum to eliminate ANY pathogens
How is the frequency of resistance to two drugs calculated?
Multiply individual frequencies of resistance.
Toxicity at the primary site of drug excretion.
Nephrotoxicity
Toxicity at the primary site of drug metabolism.
Hepatotoxicity
Nephrotoxicity
Toxicity at the primary site of drug excretion.
Hepatotoxicity
Toxicity at the primary site of drug metabolism.
Possible result of treatment with an antibiotic, especially if it is broad spectrum?
Superinfections, especially due to alterations in normal GI flora (*Clostridium dificil)
What is a possible result of poor adherence or subtherapeutic dosage of antibiotic?
Bacteria without resistance are selected against, and the surviving bacteria cannot be killed with antibiotic.
Qualities of an ideal antibiotic. (5)
- bacteriocidal (preferably in 5-7 days)
- narrowest spectrum possible
- high tissue concentration (above minimal lethal concentration of abx)
- long half-life
- Nontoxic to animal cells
How can you extend the expression of a particular drug?
Combining it with another antibiotic or other specific agents
Bacteriostatic of Bactericidal: Erythromycin
Bacteriostatic
Bacteriostatic of Bactericidal: Penicillin
Bactericidal
