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29 Cards in this Set
- Front
- Back
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What is the mechanism of action for vancomycin?
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- inhibits cell wall synthesis
- binds D-ala-D-ala when in cell wall - NOT transpeptidase inhibitor |
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What might you use to treat CA-MRSA?
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- resistant to beta-lactams
- sensitive to clindamycin, trimethoprim / sulfamethoxazole |
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What might you use to treat HA-MRSA?
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- very high level of resistance to beta-lactams
- vancomycin indicated |
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How did intermediate resistance in s. aureus come about?
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- Vancomycin intermediate level resistance in s. aureus
- from pts on long-term tx with vanco |
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How do you characterize VISA?
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- MIC of 8 ug/ml for vancomycin
- see overproduction of PBP2 / PBP2a - overproduction of peptidoglycan (big cell wall) |
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Compared to normal VSSA, in VISA you will see...
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- much thicker cell wall
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Why is the thicker cell wall of VISA important?
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- makes it more difficult for vancomycin to penetrate and kill bacteria
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An MIC value of ___ indicates high level resistance to vancomycin
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32 ug/ml
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what genetic element led to the emergence of VRSA?
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- transposon from plasmid in Enterococcus (VRE)
- 5 polypeptides requierd for resistnace |
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in VR bacteria what does the terminal sequence on the cell wall look like?
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- instead of d-ala-d-ala it is d-ala-d-lactate
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absorption of vanco
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- NOT from GI, needs to be IV
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distribution of vanco
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- well-distributed
- poor CSF penetration |
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metabolism of vanco
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- little
t1/2 = 6 hours |
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excretion of vanco
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- glomerular filtration (renal)
- mostly unchanged |
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vanco is BC or BS?
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bacteridical!
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When is vanco therapy indicated?
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- serious infections
- HA-MRSA - clostridium difficile (orally) - used primarily against gram + |
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Adverse effects of vanco
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- hypersensitivity
- ototoxicity - nephrotoxicity - red man syndrome |
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What is the structure of daptomycin?
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cyclic lipopeptide
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mechanism of action of daptomycin
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- binds bac. membrane (Ca2+ dependent)
- allows ions out - bactericidal - primarily gram + |
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mechanism of resistance of daptomycin
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- change in bacterial membrane
- change in regulatory system |
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absorption of daptomycin
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IV
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distribution of dapto
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- plasma and interstitial
- NOT CSF! (b/c charged molecule) |
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metabolism of dapto
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- little
- t1/2 - 8hr |
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excretion of dapto
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renal
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Clinical uses of dapto
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- skin, soft tissue infections
- VISA, VRSA - reserve for complicated infections |
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adverse effects of dapto
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- GI irritation
- elevation of creatine phosphokinase |
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What drug interaction needs to be considered when administering dapto?
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- statins
- lead to increased chance of muscle injury |
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What time intervals are better for dosing of dapto?
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- less frequently (24 hours) better because muscle may have time to repair
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What is an increase of creatine phosphokinase an indicator of?
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- skeletal muscle injury
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