Intro to ABx Lecture Sep 9 Flashcards
In what two general ways can an ABx be toxic?
- As an extension of mechanism of action: trimethroprim can inhibit folate metabolism in humans, resulting in bone-marrow suppression
- Unintended consequences that are not extensions of the mechanism of action: vancomycin can stimulate histoamine release resultilng in red man syndrome
What are the spectriums?
Narrow: gram negative cocci
Extended: gram negative rods and cocci
Broad: many gram positive and negative organisms
WHat is pre-emptive therapy?
When you have lab tests indicating infection but no xymptoms.
What is suppressive therapy?
After the initial disease is controlled, therapy is continued at a lower dose–esp for immunocompromised.
What are the 9 potential drug administration routes?
- oral
- intravenous
- intramuscular
- subcutaneous
- inhalant
- sublingual
- intrathecal (into CSF)
- rectal
- topical
Is a rapid antigen detection test more specific or more sensitive?
It’s more specific (95%) than sensitive (80-90%)
May haev a flase negative or infection could be due to another bacterial organism
What does the catalase test look for?
What is it used to differentiae?
monitors degradation of H2)2
differentiates between staphylococci (positive) and streptococci (nevative)
What does the coagulase look for? WHat does it differentiate between?
It looks for clumping factor.
Differentiates between staphylococcus strains.
What does a hemolysis test look for?
What does it differentiate between?
It looks for clearing around colonies on a blood agar plate
alpha–hemolytic form green ring
beta - hemolytic clearing around colonies (yellow)
gamma- no hermolysis
Differentiates between stretococci
What is the treatment of choice for strep throat?
Penicillin
What two drug classes have the most durg reactions?
beta lactams
sulfonamides
Why do you have to reduce the dose of beta lactams, aminoglycoidies, and fluoroquinolones ina patient with reduced kidney function?
They’re all excreted by the kidney, so with poor kidney funtion they’ll build up in the body.
Why does chloramphenicol dose need to be reduced if a patient has liver failure?
Chloramphenicol is inactivated by liver metabolism
What is a genetic factor that argues against using sulfonamides?
people with G6P dehydrogenase deficiency will have hemolysis of RBCs if given sulfonamides
What is the minimum inhibitory concentration?
The lowest concentration of antibiotic that prevents visible growth in culture
If MIC is lower than breakpoint then the bacterium is considered susceptible
