|
Principle
- Most of the Enterococci have the ability to hydrolyze esculin to esculetin and dextrose. Pfizer Selective Enterococcus agar base is composed of tryptone, peptone, yeast extract, esculin, bile salt, sodium azide, sodium chloride, sodium citrate ferric ammonium citrate, and agar.
- Tryptone and peptone provide nitrogen and other necessary minerals. Yeast extract supplements with essential vitamins and growth factors. Bile salt acts as a selective agent that inhibits gram-positive bacteria other than enterococci.
- Ferric citrate is an indicator of esculin hydrolysis. The esculin (glycoside) is the source of carbon. The esculin hydrolyzing microorganisms hydrolyzes esculin to esculetin and dextrose.
- The esculetin reacts with ferric ammonium citrate to form a brown or black color complex. Sodium chloride balances the osmotic balance of the medium, Agar is the solidifying agent.
|
