Abx vs. gram-pos organisms Flashcards
What are the 3 phenotypes of vancomycin resistance?
vanA, vanB, vanC
What group of organisms is vancomycin capable of killing? (name the class and the 5 major targets)
Gram-pos ONLY - *MRSA, *MSSA, *coag-negative staph, *PRSP, *c-dif (clostridium spp.) - Also targets other strep pneumoniae, viridians strep, group strep, enterococcus, corynebacterium, bacillus, listeria, actinomyces, clostridium spp., peptococcus, peptostreptococcus.
Since vanc is distributed widely in the tissues, you should use ________________ for dosing.
TBW (total body weight?)
How long does it take for vanc to distribute into the tissues?
1 hour - Peak should be drawn 1 hr post-infusion
For vancomycin, elimination T1/2 depends on _______ function.
renal function
Can pts who are allergic to PCNs be given vancomycin?
Yes! (different structure)
What’s an e.g. of a target of vancomycin that is a multi-drug-resistant bacterium?
PCN-resistant streptococcus pneumoniae (PRSP)
Vanc treats ______-______ c-dif colitis.
moderate-severe
Recall: what drug is used to treat mild-mod c-diff?
Metronidazole
How does Red Man Syndrome occur? - Which drug is it a/w?
Infusion of vancomycin at too high a RATE - Also a/w other glycopeptides
In what specific type of infection would you prefer the 2nd gen glycopeptide dalbavancin to vancomycin? - Which genes must be present?
VRE (must have vanB or vanC gene, not vanA.)
What is the MoA of vancomycin?
Binds D-ala-D-ala to inhibit cell wall synthesis
What is the MoA of linezolid? (is resistance common or uncommon?)
Binds 50S ribosomal binding site (resistance rare)
What is the major class that linezolid can inhibit? List the main targets. - What is the other class?
Gram-pos: - *MSSA - *MRSA - *VRSA, - strep-pneumoniae (including *PRSP), - **enterococcus faecium and faecalis (including *VRE) Also: viridian streptococci, group streptococci, coag-neg staph, bacillis, listeria, clostridium spp (except c-diff), peptostreptococcus, c. acnes. Atypical bacteria: mycobacteria
What is unique about the pharmacology of linezolid?
100% bioavailable
What major category of pathogens is linezolid generally used for? What body area category is it NOT used for?
* Serious/complicated infections caused by resistant gram-positive bacteria: - Not used for UTIs
What is linezolid contraindicated with and what condition does it cause?
- SSRIs, MAOIs - Serotonin syndrome
What are the major side effects a/w linezolid?
* Thrombocytopenia/anemia - SSRIs/MAOIs: serotonin syndrome. - Lactic acidosis - BM suppression - Neuropathy
What category of drugs are linezolid and tedizolid?
Oxazolinidones
What’s the advantage of tedizolid over linezolid? Why isn’t tedizolid prescribed more often?
- Doesn’t cause serotonin syndrome - It’s even more expensive than linezolid
What class of drugs does daptomycin belong in?
Lipopeptide
What class of bacteria is daptomycin active against? Name the bacteria. (*or at least the targeted ones).
Gram-pos: *MRSA *MSSA *VRSA coag-neg staph strep pneumoniae (including *PRSP) viridians streptococi group streptococci *Enterococcus faecium and farcalis (including *VRE)
*Daptomycin should NOT be used in the treatment of _____________.
*Pneumonia
*What is the major adverse effect a/w daptomycin?
Myopathy and CPK elevation (must continually monitor them)
