MIU Medium Base is formulated to detect motility, urease and indole production in single tube.
Casein enzymic hydrolysate provide amino acids and other nitrogenous substances. Sodium chloride maintains osmotic equilibrium. Dextrose is fermentable carbohydrate. Phenol red is the pH indicator which turns pink- red in alkaline conditions. The test cultures are stab-inoculated.
Motility and urease reactions are read before testing Indole production. Motile organisms show either diffused growth or turbidity extending away from stab inoculation line while nonmotile organisms grow along the stabline. Organisms that utilize urea, produce ammonia which makes the medium alkaline, showing pink-red colour by change in the phenol red indicator (1). Indole is produced from tryptophan present in casein enzymic hydrolysate (2,3). The indole produced combines with the aldehyde present in the Kovac's reagent to form a red complex.
Storage and Shelf-life:
Store below 30°C in tightly closed container and use freshly prepared medium . Use before expiry date on the label.
1. Rustigian and Stuart (1941) Proc. Soc. Exp. Biol. Med., 47:108.
2. McFaddin J.F. (1985) Media for Isolation-Cultivation-Identification-Maintenance of Medical Bacteria, Vol. 1, Williams and Wilkins, Baltimore
3. Ewing (1986) Edwards and Ewings 'Identification of Enterobacteriaceae', 4th ed. Elsevier Science Publishing Co., Inc., New York.