BIO205 CH10

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BIO205 CH10
2013-02-23 02:04:31
BIO205 CH10

BIO205 CH10
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  1. Who proposed the use of chemicals as "magic bullets" and how would they work?
    • Paul Ehrlich
    • bound to receptor pathogens and ignored the host
  2. What was Alexander Flemings contribution?
    he found a mold (Peniclillium notatum) in 1928 that had antibacterial action
  3. What was the first practical antimicrobial drug, and when was it discovered?
    • sulfanilimide
    • Gerhard Domagk
  4. Who coined the term "antibiotics" and discovered antimicrobials from streptomyces?
    Selman Waksman

  5. Difference between antibiotics, semisynthetics and synthetics
    • antibiotics: meaning antimicrobials produced by an organism
    • semisynthetics: chemically altered antibiotics
    • synthetics: chemicals completely made in the lab
  6. What is "selective toxicity"?
    toxic to pathogen, but no to host
  7. Compare prokaryotes, eukaryotes, and viruses in terms of how they may affect selective toxicity of drugs
    • prokaryotes: easier because there are many differences , so we have lots of drugs what work against bacteria
    • eukaryotes: harder 
    • virues: really hard since they utilize the host's enzymes and ribosomes to metabolize and replicate 
    • cant use antibiotics on viruses
  8. drug that affects the cell walls of bacteria and fungi
    Beta-lactams: natural penicillins and cephalosporins, semisynthetic penicillins- what advantage of the semisynthetics?
    • mos effective against G+ organisms
    • semisynthetics are more stable in acid environments, more readily absorbed, less susceptible to bacterial enzymes
  9. drug that affects the cell walls of bacteria and fungi
    streptomyces orientalis
  10. drug that affects the cell walls of bacteria and fungi
    drugs have no effect on dormant bacteria- cells must be growing for effect to take place
  11. drug that affects the cell walls of bacteria and fungi
    • used to treat TB
    • attack mycolic acids in cell wall of Mycobacterium tuberculosis
  12. drug that affects the cell walls of bacteria and fungi
    Echinocandins (caspofungin)
    • fungal cell walls
    • inhibit glucan synthesis, the components of fungal cell walls
  13. drugs that inhibit protein synthesis 
    change the shape of the ribosome
  14. drugs that inhibit protein synthesis 
    block tRNA docking
  15. drugs that inhibit protein synthesis 
    Chloramphenical, erythromycin
    inhibit the ribosomes
  16. drugs that inhibit protein synthesis 
    Antisense nucleic acids
    • RNA or single-stranded DNA molecules
    • complementary to specific RNA molecules in prokaryotes only
  17. drugs that disrupt the cytoplasmic membrane
    Polyenes? nystatin, amphotericin B
    • anitifungal
    • do the same thing by attaching to a component of fungal cell membranes called ergosterol
  18. drugs that disrupt the cytoplasmic membrane
    • antifungals
    • harmless to humans 
    • prevents synthesis of ergosterol
  19. drugs that disrupt the cytoplasmic membrane
    • effective against G-
    • Pseudomonas
  20. drugs that inhibit metabolic pathways 
    • sulfa drugs
    • structural analog of PABA 
    • is important in making folic acid
  21. drugs that inhibit metabolic pathways 
    • prevents uncoating of viruses 
    • can't replicate
  22. drugs that inhibit metabolic pathways 
    Protease inhibitors?
    • inhibit protease
    • is needed for HIV reproduction
  23. Describe actions and give examples of drugs that inhibit nucleic acid synthesis including:
    Nucleotides analogs (quinolones, rifampin, AZT)?
    • structurally similar to nucleotides (A, T, C, G)
    • incorporated into DNA or RNA and prevent replication, transcription or translation- distort the molecules
    • quinolones- prokaryotes only
    • Rifampin- anti- TB drug
  24. What are the primary clinical considerations a doctor must consider when choosing an antimicrobial drug?
    • range of pathogens against which they are effective
    • efficacy, including dosages required to be effective
    • routes by which they are administered
    • overall safety
    • side effects produced
  25. compare broad-spectrum drugs with narrow spectrum drugs
    • broad- tetracycline, effective against G+, G-, chlamydias, rickettsias and may allow secondary infections to arise
    • narrow- penicillin effective against G+ can't easily penetrate outer membrane of G-
  26. what factors determine the size of the zone of inhibition in the Kirby-Bauer tests?
    • effectiveness of drug
    • ability to diffuse
  27. Describe/compare the four routes of administering antimicrobial drugs.
    • topically- drug applied directly, skin
    • orally- simplest, but drug concentration in the body is low
    • IM- intramuscular administration, slowly diffuses into blood vessels, not as high of a concentration as with IV
    • IV- intravenous administration, kidneys and liver rapidly remove drug unless it is continuously administered
  28. describe safety and side effect including:
    • many drugs have toxic side effects
    • kidneys, liver, nerves: polymyxin and aminoglycosides can have fatal effects on the kidneys
    • have to be careful when prescribing for pregnant women
  29. describe safety and side effect including:
    • may result in anaphylactic shock, which can be life- threatening
    • o.1% of people are allergic to penicillin
  30. describe safety and side effect including:
    Disruption of normal flora?
    • normal flora that is unaffected by drug may overgrow, causing superinfection
    • clostridium difficile in the colon causing pseudomembranous colitis, fatal
  31. What is antimicrobial drug resistance, and how can it be avoided?
    • Microbes can become resistant: new mutations of chromosomal genes, acquiring plasmids wityh genes that confer resistance-R- plasmids
    • occurs among bacteria, viruses and protozoa
    • may destroy or inactivate the drug
    • avoid- using high concentration of the drug for along enough time to kill all sensitive cells and inhibit others so body can defend
    • use combinations of drugs
    • limit the use of antimicrobials to necessary cases