Card Set Information

2011-02-14 22:01:58
micro quiz

phenol red broth, oxidation fermentation test, MR and VP test, Catalase test, citrate test
Show Answers:

  1. Phenol Red Broth
    looks for fermentation of sugars (glucose, fructose, sucrose) which is indicated by gas (durham tube) and color change due to acid
  2. Color indication phenol red broth
    • Yellow broth w/ bubble is acid and gas end products
    • Yellow broth no bubble is acid but no gas
    • Red broth no fermentation
    • pink broth is alkaline end product
  3. Oxidation fermentation test
    • carbohydrates are oxidized to pyruvate
    • low agar concentration
    • 2 tubes stab inoculated
    • after inoculaton 1 tube place mineral oil
    • the other leave unsealed.
  4. Oxidation fermentation test
    • yellow throughout is oxidation and fermentation or only fermentation
    • green/blue (w/ any amount of yellow) oxidation
    • slightly yellow on top is oxidation and slow fermentation or only slow fermentation
    • green/blue (no yellow) is no sugar metabolism
  5. Methyl Red and Voges-Proskauer Tests (MR &VP)
    • Combo medium
    • MR= detects organisms capable of performing a mixed acid fermentation.
    • verified w/ methyl red indicator. red= + result, acidic
    • VP= organism ferment glucose quickly convert products to aceotoin and 2,3 butendoil red= + result alkaline
  6. Catalase Test
    • Potent cellular toxins hydrogen peroxide and superoxide radical
    • Has to w/ ETC- Flavoprotein- Catalase
    • Bubble- catalse present
    • No bubble- catalase absent
  7. Citrate Test
    • In many bacteria citrate produced as acetyl Co A reacts w/ oxaloacetate at entry Krebs
    • only available carbon source
    • pyruvate converted by citrate- permease
    • Ammonia phosphate sole nitrogen source
    • agar called simmons citrate agar
  8. Citrate Test color indicators
    • Blue (even a samll amount) is citrate utilized
    • no color change but growth is citrate utilized
    • No color change and no growth is not utilized