MIC 541-Exam 4- Antimicrobials V-3

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MIC 541-Exam 4- Antimicrobials V-3
2013-04-14 21:05:53
MIC 541 Exam Antimicrobials

MIC 541-Exam 4- Antimicrobials V-3
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  1. What are low affinity PBPs?
    Mutated PBPs that have a lower affinity for certain B-lactam antibiotics than in their native form
  2. Mutated PBPs that have a lower affinity for B-lactam Antibiotics than in their native form are called what?
    Low affinity PBPs
  3. What low affinity PBPs were presented in class?
    • PBP 5
    • PBO 2a and 2
    • Others: those in PRSP and PISP
  4. PBP 5 is found in what bacteria?
  5. Enterococci carry what type of Low affinity PBPs?
    PBP 5
  6. What bacteria are PBP 2a and 2' in?
    • Staphylococci
    • MRSA
  7. Prior to 1990, what bacteria was not tested for susceptibility?
    S. pneumoniae
  8. What are the only drugs that S. pneumoniae not resistnat to today?
    Glycopeptides and flouroquinolones
  9. What very resistant bacteria is susceptible to glycopeptide and flouroquinolones?
    S. pneumoniae
  10. Since 1990 what resistant bacteria has emerged?
    S. pneumoniae
  11. How does S. pneumoniae develop resistance?
    • mutate PBPs
    • foreign DNA from other Sterptococci
  12. How is S. mitis important to S. pneumoniae resistance?
    S. mitis dies in the mouth and S. pneumoniae scavenges the DNA for resistance
  13. What has been the main avenue for S. pneumoniae to gain resistance to Penicillins?
    Scavenged DNA (particularly from S. mitis)
  14. When was the first time that we realized we had penicillinases in S. aureus?
  15. When did the first MRSA emerge?
  16. MRSA is resistant to what?
    All B-lactams except ceftaroline
  17. MRSA is resistant to all B-lactams except which one?
  18. 50% of isolates in hospitals are what type of S. aureus?
  19. How common is MRSA in hospitals?
    50% of isolates
  20. What areas are MRSA spreading in?
    • Community
    • Nosocomial
    • Veterinary
  21. What are examples of glycopeptides?
    • Vancomycin
    • Teicoplanin
    • Telavancin
  22. Vancomycin, Teicoplanin and Telavancin are of what antibacterial group?
  23. What is teh Molecular weight of Glycopeptides?
    Over 1000
  24. Are Glycopeptides active against Gram negatives?
    No, they are too big to cross the porins in the outer membrane
  25. Why are glycopeptides not active against Gram negative bacteria?
    They are too large to cross through porins of the outer membrane
  26. Why is Vancomycin the drug of last resort?
    It is Toxic
  27. What type of bacteria can Vancomycin protect against?
    Gram positive
  28. Why is Vancomycin used?
    For very resistant bacteria
  29. How long did take for Enterococcus to develop resistance to Vancomycin ?
    30 years
  30. How many genes did the Enterococcus have to develop to become resistant to Vancomycin?
    8 genes
  31. The resistance for what is encoded on 8 genes?
  32. What are the 8 genes that infer resistance for Vancomycin called?
    Van genes
  33. What is the mechanism of Van genes resistance?
    Altered target
  34. What is a VRE?
    Vancomycin resistant enterococci
  35. VRE has van genes that alter what?
    The target
  36. Resistance to vancomycin in MRSA took how long to develop?
    40 years
  37. What type of resistance to vancomycin developed in MRSA?
  38. What bacteria developed an intermediate resistance to Vancomycin?
  39. What is the mechanism of Vancomycin intermediate-resistance in MRSA?
    thicker cell wall that binds the drug and blocks it from the PBPs
  40. What is VISA/GISA?
    • Vancomycin intermediate staphylococcus aureus
    • AND the newer name
    • Glycopeptide intermediate staph aureus
  41. What bacteria developed thicker walls to block vancomycin?
  42. What bacteria is referred to as VISA/GISA?
    MRSA with intermediate  Vancomycin resistance
  43. What is the name for Vancomycin intermediate-resistant MRSA?
    VISA or GISA