Media types

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Media types
2012-02-13 12:48:25

Basic, enriched, differential,selective types of media and their functions
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  1. Name 4 types of media
    • basic
    • enriched
    • differential
    • selective
  2. basic Media
    has basic nutrients to allow growth

    most bacteria of clinical interest will grow
  3. enriched Media
    has additional stuff for organisms that need more
  4. Differential media
    tell organism different because of what happened to plate hemolysis, color change
  5. Selective media
    encourages or inhibits growth of specific organisms
  6. Blood Agar
    • Enriched and Differential
    • contains 5% sheep blood
    • alpha, beta, and gamma Hemolysis
  7. hemolysis
    RBC destroyed
  8. mannitol salt agar
    • selective and differential
    • selects for halophiles--salt lovers grow in salt environment
    • differentiates between
    • S. Aureua ---- changes from pink to yellow
    • S. epidermidis---- does not change color
    • inhibits growth of nonhalophiles and encourages growth of halophiles
    • phenol red ph indicator
  9. alpha hemolysis
    causes an area of green to appear in the agar surrounding the bacterial colonies

    alpha hemolysis is incomplete hemolysis
  10. beta hemolysis
    causes a clear area to appear in the agar surrounding the bacterial colonies

    is complete lysing of blood content by colony
  11. gama hemolysis
    occurs when there is no hemolysis present int he agar surrounding the bacterial colonies

    no hemolysis
  12. MacConkey agar
    • selective, differential
    • bile salts, crystal violet, lactose, neutral red indicator
    • inhibits gram positives
    • lactose fermenters turn red/pink
    • neutral red indicator
    • biles salts, and crystal violet inhibit growth of gram positive bacteria
  13. phenlyethyl alcohol (PEA)
    • phenylethanol
    • 5% sheep blood
    • smells like flowers
    • inhibits anaerobic gram neg bacilli
    • supports gram positives
  14. hektoen
    • changes from green to blue in alkaline environment
    • bile salts, lactose, sucrose alicin, ferric ammonium citrate, bromthymol blue and acid fuchsin indicators (ph indicators)
    • green media
    • selective differential
    • salmonella black center
    • shigella no black center
    • supports gram neg
  15. bile esculin (BE)
    • light brown in slant
    • ecoli will grow with no color change
    • bile salts, esculin,ferric citrate
    • selective, differential
    • bile turn the medium black
    • enterococcus opportnisists only to grow this
  16. simmons citrate
    • green
    • citrate bromthymol blue indicator
    • salmonella pseudomonas
    • change from green to bright blue
    • selective and differential