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Principle
- Hektoen Enteric Agar is consisting protease peptone, yeast extract, bile salt mixture, lactose, sucrose, salicin, sodium chloride, sodium thiosulphate and ferric ammonium citrate, and acid fuchsin, bromothymol blue and agar.
- It is resourceful for the recovery rate of Salmonella sp. Protease peptone provides nitrogen, carbon, and amino acids required for organism growth. Yeast extract provides essential carbon, vitamin, nitrogen, and amino acids sources.
- Bile salts inhibit the growth of most Gram-positive organisms. Lactose, salicin, and sucrose serves as carbon source, added in media to boost the growth and differentiation of enteric bacteria. Sodium chloride maintains the osmotic equilibrium.
- Sodium thiosulfate serves as a source of sulfur. Ferric ammonium citrate was added to the medium to detect hydrogen sulfide production. Ferric ammonium citrate serves as an iron source, and in presence of sodium thiosulphate produce hydrogen sulfide gas to form a black precipitate.
- The bromothymol blue and acid fuchsin are pH indicators, the bacteria capable of fermenting one or more of the carbohydrates produces yellow- or orange-colored colonies like Klebsiella pneumoniae, that ferments lactose. While the Enterobacters that are Non-fermenters will produce blue-green colonies.
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