YERSINIA SELECTIVE AGAR
Yersinia Selective Agar is used for the selective isolation and cultivation of the food- and water-borne pathogen Yersinia enterocolitica. Enzymatic Digests of Gelatin, Casein, and Animal Tissue provide the nitrogenous sources essential for the growth of this bacterium. Yeast Extract is the vitamin source. Selectivity is achieved due to the presence of Sodium Deoxycholate, Sodium Cholate, Crystal Violet, and Irgasan, which inhibit the growth of Gram-positive and many Gram-negative organisms. Additionally, supplementation with Cefsulodin and Novobiocin improves inhibition of normal enteric organisms. Mannitol is the fermentable carbohydrate. Microorganisms capable of utilizing it, such as Y. enterocolitica, acidify the growth medium and absorb the pH indicator Neutral Red, thus forming pink-red colonies. In turn, non-mannitol-fermenting species produce colorless colonies. Sodium Chloride maintains osmotic balance, while Sodium Pyruvate and Magnesium Sulfate serve as growth enhancers. Agar is the gelifying agent.