raines 1 more difficult

  1. test to distinguish staph from strep
    • catalase test.
    • strep is catalase negative
  2. strep is gram [+ or -]
    + positive
  3. poor availability oral antibiotics
    • aminoglycosides
    • vancomycin
  4. 40L Vd
    40 liter volume distribution: drug distributes throughout the body fluids (gets to every single space in your body)
  5. example: taking a drug q8, you won't be killing anymore by the end of each dose, but you won't be in the black long enough for the infection to take over. then comes the next dose.

    what is this called, and what class of meds works like this?
    • time-dependent antibiotic killing
    • penicillins utilize this
  6. drugs that kill when the concentration at the bacterial site is higher than the MIC of the organism, and 4 examples
    time-dependent antibiotic killing.

    examples: carbapenems, vancomycin, macrolides, clindamycin
  7. highly bioavailable oral antibiotics (6)
    • quinolones (ciprofloxacin, moxifloxacin)
    • TMP-SMX
    • clindamycin
    • doxycycline
    • rifampin
    • azoles
  8. combining beta lactases does this
    increases the spectrum of activity

    • gram + MSSA
    • gram - H flu, E coli, Klebsiella
    • anaerobes: B frag
  9. these are antibiotics that expand the spectrum of specific beta-lactams by binding irreversibly to beta lactamase produced by the organism
    beta lactamase inhibitors
  10. 3 beta lactamase inhibitors and what they do
    • sulbactam
    • tazobactam
    • clavulanate

    these get into the beta lactamase and keep it from working
  11. half lives of oxacillin and nafcillin are
    SHORT! 0.5 hrs. requires frequent dosing (q4 IV)

    cleared hepatically (no need to adjust for renal, like you do with penicillin G)
  12. side effects of ampicillin/amoxicillin
    • rash
    • diarrhea (diarrhea worse with ampicillin. amox better for diarrhea)
  13. a semisynthetic penicillin
  14. semisynthetic penicillin good against gram + cocci:
    S. pneumoniae
    Groups A, B, C, G strep
    S aureus
    S epidermidis
  15. 25-30L Vd
    • 25-30 liter volume distribution
    • drug distributes intracellularly
  16. 10-20L Vd
    10-20 liter volume distribution

    drug distributes into extracellular compartments
  17. 5L Vd
    5 liter volume distribution

    indicates antibiotic is restricted to circulatory system
  18. piperacillin-tazobactam combined with this, is very powerful

    *tazobactam does not cover MRSA
  19. a ureido penicillin, similar to ampicillin against gram+. good against streptococci. expanded gram- coverage including Pseudomonas aeruginosa, Serratia marsescens, Enterobacter
    good against B frag
  20. pip-taz is short for
  21. ampicillin-sulbactam and amoxicillin-clavulanate are better than amp/amox alone for:
    • pneumonia
    • H flu
    • S aureus
    • intra-abdominal infections (but needs better E coli coverage)
    • skin and soft tissue
  22. ampicillin-sulbactam is always given this way
  23. useful for nosocomial pneumonia, intra-abdominal infections, complicated wound infections, peudomonal infections, but very expensive
  24. for Enterococci: ampicillin/amoxicillin vs penicillin
    ampicillin and amoxicillin are 2x more active on Enterococci than penicillin
  25. penicillin side effects
    • rash
    • anaphylaxis/urticaria
    • hyperkalemia
    • seizures
  26. penicillin G repository (IM) formulations and why
    1. procaine + Penicillin G delays onset of peak but gives a good 12 hour dose

    2. benzathine penicillin combined with ammonium base: gives serum levels for 15-30 days. not powerful enough for CNS infections.

    these are good for populations who 'don't come back' like travelers and careless teenagers
  27. Penicillin G half life is
    • very short! 0.5 hrs
    • IV dosing q4

    • cleared renally
    • poor oral bioavailability
  28. Penicillin G vs. spirochetes, cat bites
    • penicillin G has good activity against
    • T. pallidum (syphilis)
    • B. burgdorferi (Lyme)
    • Pasteurella multocida (cat bites)
  29. Penicillin G vs. anaerobes
    • good activity against oral anaerobes:
    • Peptostreptococcus
    • Prevatella
    • Fusobacterium
    • *Clostridium

    not good for B frag and other B. therefore not good for intra-abdominal infections
  30. how to measure MIC and why
    millimeters of zone of inhibition (clear zone) correlates directly with MIC units (ug/ml)

    to see if antibiotic is sensitive, intermediate or resistant
  31. therapy for coagulase-negative staph infection
    • remove implanted catheter or device
    • vancomycin

    (majority of these bugs are resistant to all beta-lactam agents)
  32. therapy for VISA or VRSA staph infections
    daptomycin, linezolid
  33. therapy for HA-MRSA (healthcare-acquired MRSA staph infection)
    • vancomycin
    • daptomycin, linezolid or quinupristin-dalfopristin
  34. therapy for CA-MRSA (community-acquired MRSA staph infection)
    for minor/moderate: trimethoprin-sulfamethoxazole, clindamycin, doxycycline, minocycline, linezolid

    for severe: vancomycin
  35. therapy for MSSA staph infection
    • oxacillin or nafcillin
    • 1st or 2nd generation cephalosporins
    • vancomycin
  36. ampicillin half life
    • short! 0.5 hours. frequent dosing q4-6
    • cleared renally (must adjust)
    • use amoxicillin for oral. this only has fair oral bioavailability
  37. viridans vs Penicillin
    very sensitive. PCN works great on viridans.
  38. strep. pyogenes vs bacitracin
    99% sensitive to it
  39. 7 diseases caused by s. pyogenes
    strep throat, cervical lymphadenopathy, impetigo, nec fasc, rheumatic fever, scarlet fever, strep TSS
  40. s pyogenes vs PCN
    very sensitive to PCN
  41. staph aureus vs penicillin G
    NO. S. aureus contains a penicillinase
  42. Penicillin G affects these gram +
    • strep pneumoniae
    • strep pyogenes (group A)
    • strep agalactiae (group B)
    • *viridans
  43. Penicillin G affects this gram-
    Neisseria meningitidis

    note: not useful against gonorrhea
  44. semisynthetic penicillins (methicillin) are not active against gram
    gram negative
  45. oral bioavailability of oxacillin, nafcillin
    poor bioavailability! use dicloxacillin instead
  46. aminopenicillins vs Klebsiella, serratia, acinetobacter, Pseudomonas, B frag
    NO. these are resistant to aminopenicillins
  47. aminopenicillins vs gram-
    • YES.
    • H flu
    • E coli
    • Proteus mirabilis
  48. aminopenicillins are good for gram:
  49. aminopenicillins vs penicillin-susceptible S. aureus
    aminopenicillins are active against PCN-susceptible S. aureus

    (BUT this is only 2% of all S. aureus)
  50. 3 factors affecting the bioavailability of oral antibiotics
    • intestinal cytochrome enzymes
    • intestinal transporter systems (P glycoprotein)
    • decreased intestinal absorption (malabsorption, presence/absence of food, diarrhea)
  51. some drugs need to be modified by this system to be biologically active
    CYP (cytochrome P450)
  52. a group of isoenzymes located primarily in the liver and GI tract
    cytochrome P450 system
  53. penicillin's mechanism
    penicillins work by using BETA LACTAM to inhibit cell wall synthesis. bacteria produce beta lactamase enzymes and if the enzyme eats the beta lactam in the antibiotic, the bacteria becomes resistant to the medicine.
  54. if CYP is being inhibited for a certain drug, this is called [up-regulation, down-regulation] and the drug level will be [increased, decreased]
    down-regulation, and the drug level will be increased
  55. if CYP is being induced for a certain drug, this is called
    [up-regulation, down-regulation] and the drug level will be [increased,
    up-regulation, the drug level will be decreased
  56. AUC
    area under the curve: time above the MIC
  57. covers MSSA, good for beta-lactamase producing Enterobacteriae (E Coli, Klebsiella) but 8% of E Coli are resistant

    95% of B frag covered
  58. pip-tazo half life
    • short! 1 hr.
    • frequent dosing q6 or q8 IV
    • cleared renally (must adjust)

  59. concentration-dependent antibiotic killing
    higher single dose better than smaller multiple doses

    aminoglycosides and quinolones
  60. strawberry tongue means
    scarlet fever. sometimes accompanies strep throat. desquamating skin, too. caused by a phage.
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raines 1 more difficult
raines 1 more difficult