micro...

looks for fermentation of sugars (glucose, fructose, sucrose) which is indicated by gas (durham tube) and color change due to acid

• 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

• carbohydrates are oxidized to pyruvate
• low agar concentration
• 2 tubes stab inoculated
• after inoculaton 1 tube place mineral oil
• the other leave unsealed.

• 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

• 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

• Potent cellular toxins hydrogen peroxide and superoxide radical
• Has to w/ ETC- Flavoprotein- Catalase
• Bubble- catalse present
• No bubble- catalase absent

• 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

• 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