Test 2 Micro (Ppts 9-12)

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BrookeNH10
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Test 2 Micro (Ppts 9-12)
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2012-10-25 17:21:52
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Antibiotics
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Antibiotics
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  1. One drug may damage a vacterium and render it more susceptible to the action of another drug.
    • Synergy
    • (Ex.  A cell wall damaging drug can often allow a drug that binds ribosomes to enter the cell more efficiently)
  2. Beta-lactams are _______ inhibitors that kill _________ bacteria. They are destroyed by beta-lactamases.
    cell wall, growing
  3. Blocks cell wall synthesis by binding to newly made cell wall subunits (only in Gram-P bacteria).
    Vancomycin
  4. Vancomycin:
    Bacteriocidal or bacteriostatic?
    Fast or slow?
    Gram-N or Gram-P?
    • Bacteriocidal
    • Slow
    • Gram-P
    • Used for drug-resistant Gram-P strains and for similar infections in patients alleric to penicillins.
    • Does have some toxicity.
  5. Name 2 aminoglycosides.
    Aminoglycosides inhibit?
    Used to treat?
    Administered by?
    • Gentamicin, Tobramicin
    • Protein synthesis (kill bacteria)
    • Broad spectrum (but will not enter anaerobic bacteria or our cells);  used synergistically with many cell wall specific antibiotics (beta-lactam or vancomycin) b/c they increase aminoglycoside entry into the bacterium
    • IV
  6. Oral drugs that indirectly (block folic acid synthesis) and synergistically stop DNA synthesis and can kill bacteria in urine.
    Sulfa-Trimethoprim
  7. Oral drugs that affect DNA synthesis, can kill bacteria, broad spectrum drugs, expensive but popular.
    Fluorquinolones
  8. Name 2 drugs affecting DNA synthesis.
    Sulfa-Trimethoprim, Fluoroquinolones
  9. With Sulfa-Trimethoprim, how do most bacteria stay alive?  Which bacteria are killed?
    Most bacteria can stay barely alive by stealing enough folic acid or thymidine from their surrounding tissues.  Bacteria in the urine are killed.
  10. Which antibiotic was used in the anthrax attacks?  What category of antibiotic is it?
    Cipro, fluoroquinolone (DNA synthesis)
  11. Enterobacteriaceae (E.coli and Klebsiella)
    Gram-P or Gram-N?
    Shape, arrangement?
    Aerobic or anaerobic?
    • Gram-N
    • Single rods
    • Anaerobic (ferment glucose)
  12. Pseudomonas (like enterobacteriaceae it is also Gram-N) what is its main difference?
    Aerobic (Oxidase +)
  13. Enterobacteriaceae, do they cause CA or nosocomial infections?
    Both
  14. What is the #1 cause of UTI?
    E. coli
  15. What two drugs do you treat urinary tract infections with?
    Which one has a better chance of killing the bacteria?
    • Sulfa-trimethoprim, fluoroquinolone
    • Fluoroquinolone
  16. Pseudomonas is the #1 cause of:
    • Corneal infections
    • Otitis external
    • Burn infections
    • Lower respiratory tract infections

    Also causes CF (lung)
  17. Pseudomonas has an inherent Bla, so you must use?
    • Advanced penicillins or cephalosporins
    • B-lactam + aminoglycoside
    • Fluroquinolone for oral or IV use
  18. 3 Main Gram-P bacteria causing resistance problems.
    • Staphylococcus
    • Enterococcus
    • Streptococcus pneumoniae
  19. How do you treat MRSA?
    IV vancomycin
  20. Name the 2 resistant types of staph. aureus
    • MRSA
    • VISA (vacomycin intermediately resistant strains)
  21. MRSA is based on?
    Staph chromosome cassette (SCCmec)
  22. mec gene encodes for?
    Resistance to all Beta-lactams (makes the active site too small- MRSA Staph)
  23. Staph. aureus: Common Therapies
    Restistance due to Beta-Lactamase
    Treat with?
    Anti-Staph Penicillin or cephalosporin
  24. Staph. aureus: Common Therapies
    Restistance due to MRSA
    Treat with?
    Vancomycin
  25. Staph. aureus: Common Therapies
    Restistance due to CA-MRSA
    Treat with?
    Sulfa-trimethoprime, clindamycin
  26. S. epidermidis can cause a biofilm layer.  Especially on
    implants
  27. Treat normal plasmid-bearing strains of Staphylococcus epidermidis with?
    Penicillin or cephalosporin
  28. Treat MRSE with?
    Vancomycin
  29. Enterococcus:
    Gram-P or Gram-N?
    Shape, arrangement?
    Lives in the gut, very resistant to drying
    • Gram-P
    • Cocci in pairs or short chains
  30. Enterococcus can cause
    • UTI
    • Endocarditis
    • Wound infections
    • Oral infection
  31. S. aureus, S. epidermidis, and Enterococcus are all Gram-P cocci that cause _________
    Opportunistic infections
  32. Enterococcus Therapy:
    Outpatient?
    Inpatient?
    • Outpatient:  Oral penicillin or ampicillin or fluoroquinolone
    • Inpatient:  IV penicillin + aminoglycoside or IV vancomycin + aminoglycoside
  33. Enterococus has intrinsic resistance, expecially against
    PBPs
  34. Plasmids can code for VRE.  What is VRE?
    Vancomycin Resistant Enterococcus
  35. Lancet-shaped diploccoci found in the upper respiratory flora of many healthy people.
    Streptococcus pneumoniae
  36. Which gram-P cocci benefits from exogenous catalase and is sensitive to oxidizing agents?
    Streptococcus pneumoniae
  37. Pneumococcus causes
    • Meningitis
    • Otitis media
    • Pneumonia

    Produces pneumonlysin (virulence factor)
  38. H. influenzae:
    Gram-P or Gram-N?
    Shape?
    Fastidious, with what special growth needs?
    Where is it found?
    • Gram-N
    • Pleomorphic
    • NAD, heme
    • Flora of upper respiratory tract
  39. 2 Life threatening illnesses H. flu can cause.
    Name 3 other things it can cause.
    • Epiglottitis
    • Meningitis

    • Pneumonia
    • Otitis Media
    • Conjunctivitis
  40. Treat meningitis from H. flu with?
    Cephalosporin
  41. Neisseria gonorrhoeae:
    Gram-P or Gram-N?
    Shape, arrangement?
    Treat with?
    • Gram-N
    • Diplococcus (two red beans)
    • Cephalosporin
  42. Bacteroides fragilis:
    Gram-P or Gram-N?
    Shape, arrangement?
    Aerobic, anaerobic?
    Found?
    Produces Bla, so treat w/?
    • Gram-N
    • Pleomorph found in singles
    • Strict anaerobe
    • Large intestine, mucous membranes
    • Treat w/ advanced penicillin/cephalosporin or penicillin +Bla inhibitor (clindamycin and metronidazole may also treat it)
  43. Mycobacterium tuberculosis:
    Gram-P or Gram-N?
    Shape, arrangment?
    Found in?
    Spread by?
    • AFB
    • Stacks of rods
    • Respiratory tract of infected people
    • Spread by droplets
  44. Which organism can be intra- and extra-cellular?
    M. tuberculosis
  45. Treat M. tuberculosis w/?
    Rifampin & isoniazid + other drugs
  46. Name the two types of resistant TB.  What are they resistant to?
    • MDR (multi-drug resistant TB):  Resistant to rifampin & isoniazid
    • XDR (Extensively drug-resistant TB):  Resistant to rifampin, isoniazid, fluoroquinolones, and to at least one 2nd line drug.
  47. Which antibiotic target has high specificity but limited value?
    Energy production
  48. Which antibiotic target has maximal specificity and maximal value?
    Cell wall synthesis
  49. Antibiotic selection and evaluation:
    Primary Visit:
    24 Hrs:
    48hrs:
    • Make empiric therapy
    • 24 hrs:  Review culture and computer data (confirm or change antibiotic)
    • 48 hrs:  Review susceptibility testing data (confirm usage vs. change antibiotics)
  50. Antibiotic Interactions:
    Sum of A + B
    Additive
  51. Antibiotic Interactions:
    More than A + B
    Synergy
  52. Antibiotic Interactions:
    Static Drug (A) + Cidal Drug (B)
    Antagonism (A static drug can block a cidal drug's effects because a cidal drug needs bacteria to grow in order to kill them.)
  53. Measuring diameters of zone inhibition is done with?
    Kirby Bauer Disc Assay
  54. MIC90
    Value that inhibits (kills) 90% of many clinical isolate of one species
  55. Best way to compare antibiotics for their potency?
    MIC90
  56. Minimal Bactericidal Concentration
    Plate concentrations from MIC tubes.  The MBC is the plate with the least amnt of antibiotic that grows no colonies. (Usually MIC or one tube below)
  57. What yields MIC values without dilutions?
    E strips
  58. Antibiotic concentration that when added to 1010 CFU allows no bacteria to survive.
    Mutant Prevention Concentration (MPC)

    It kills the spontaneous mutant.  MPC must be below the in vivo attainable concentration for a drug that will be used clinically
  59. 2 Ways to Inhibit Cell Wall Synthesis:
    • 1)  Inhibit synthesis in the cytoplasm
    • 2)  Inhibit the periplasmic enzymes required for incorporation of the subunits into the wall
  60. What 3 enzymes are required for subunit incorporation in the periplasm?
    • Autolytic
    • Polymerase
    • Transpeptidase
  61. Drug that is used 1x for UTI because rapid resistance develops.  Treats Gram-P and Gram-N
    Fosfomycin
  62. What enzyme do bacteria have that we don't?  This enzyme is a great target for antibiotics.  It convers UDP-NAG+PEPA into UDP-NAMA (ie. makes muramic acid).
    PEPA Transferase enzyme
  63. What drug inhibits PEPA Transferase enzyme?
    Fosfomycin
  64. Alanine Racemase
    Converts 2 L-ala into 2 D-ala (for cell wall).  This is the only place in nature this is found.
  65. What antibiotic inhibits alanine racemase?
    Cycloserine
  66. Phosphatase effects on Lipid-PO4
    Removes PO4 and activates BPP
  67. What antibiotic inhibits the phosphatase enzyme of BPP?
    Bacitracin
  68. Treat drug resistant TB or re-treatment of TB?
    Cycloserine
  69. Transiently reduces the # of S. aureus organisms in "Staph Carriers"
    Bacitracin
  70. Topical ointment contains bacitracin, neomycin and polymyxin.  Which are used to treat Gram-P?  Which are used to treat Gram-N?
    • Gram-P:  Bacitracin, Neomycin
    • Gram-N:  Polymyxin, Neomycin
  71. Vancomycin treats
    • Enterococcus
    • MRSA
    • MRSE
    • Tx of Gram-P infections in penicillin allergic patients
  72. Red Man Syndrome
    What is it?
    Causes?
    Vancomycin given too fast through infusion causes hyper-osmolarity at injection site --> histamine release.

    kidney damage and hearing loss

    "Vulture the indian can't hear and eats dead things --> kidney damage"
  73. Plasmid-coded enzymes can produce altered forms of the cell wall subunit that do not have the usual d-ala-d-ala.  What are these three enzymatic events?
    • Destroy any D-ala-D-ala (vanX)
    • Produce a needed chemical, usually converts pyruvate to D-lactate (vanH)
    • Attach the chemical to D-ala to Create D-ala-D-X (vanA)
  74. Vancomycin resistance found in?
    Enterococcus and Staphylococcus (VIRSA)
  75. VIRSA has
    thick cell walls
  76. Which enzyme calls cuts wall and allows the new cell wall piece to be inserted?
    Autolytic enzymes
  77. Penicillin G treats
    Streptococcus, syphylis, Neisseria meningitidis and most anaerobes (not Staph, gonococcus, nor Bacteroides)
  78. Patient has rheumatic fever.  Treat prophylactically with ______ to prevent more infections with GAS.
    Penicillin
  79. Which can be given orally?  Penicillin G or Pencillin V?
    Penicillin V
  80. Semi-synthetic drug invented for Bla-producing S. aureus; replaced with better drugs.
    Methicillin
  81. IV use for Staph ONLY infections.
    Nafcillin
  82. Oral drug with activity like that of nafcillin.
    Cloxacillin (oxacillin is used in resistance assays)
  83. Semi-synthetic drugs designed to enter non-fastidious Gram-N bacteria (broad spectrum), susceptible to BLA.
    Aminopenicillins (Ampicillins and amoxicillin)
  84. Used as prophylactic drug for dental patients to prevent endocarditis in patietns with an artificial heart valve or previous heart infection.
    Ampicillin & amoxicillin (if allergic to penicilins use clindamycin)
  85. Penicillins whose extra carboxy group allows penetration of Pseudomonas and Bacteroides, resists their intrinsic Bla (but susceptible to some plasmid-coded Bla).
    How are these used?
    Carbenicillin & Ticarcillin (IV route)
  86. Urea-like group protects the Beta-lactam ring from activity of many Bla (Used IV for Gram-N)
    Piperacillin
  87. Cephalosporins:
    Staph & Strep but not Entero
    1st Gen
  88. Cephalosporins:
    Susceptible Gram-N (Klebsiella)
    1st Gen
  89. Cephalosporins:
    Prophylaxis of "clean surgery"
    1st Gen
  90. Prophylaxis of dental patient with an implant
    1st Gen
  91. Cephalosporins:
    Prophylaxis for surgery involving mucous membranes
    2nd Gen
  92. Cephalosporins:
    Gram-N BLA producers
    2nd Gen
  93. Cefepime (4th Gen.) treats Gram-P or Gram-N?
    Both
  94. 2 Drugs that can treat MRSA.
    Certaroline (USA) & Ceftobiprole
  95. Resists Bla, but is effective only for aerobic Gram-N bacteria.
    Aztreonam (used IV, often with an aminoglycoside antibiotic)
  96. Clavulanic Acid + Amoxicillin
    Augmentin (respiratory infections)
  97. Clavulanic Acid + Ticarcillin
    Timentin (serious infections w/ Gram-N Bla-producers)
  98. Unasyn (Respiratory infections)
    Sulbactam + Ampicillin
  99. Zosyn
    • Tazobactam + Piperacillin
    • (Very serious infections w/ Gram-N Bla-producers)

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