DC Medium w/ BCIG
DC (Differential Coliform) Medium is a selective medium used for the chromogenic differentiation of Escherichia coli from other coliforms. BCIG (5-bromo-4-chloro-3-indolyl-β-D-glucuronide) detects the activity of β-glucuronidase, which is specific of E. coli, by the formation of blue-purple colonies. Bile Salts inhibit Gram-positive bacteria and spore-forming microorganisms while enhancing that of E. coli. Proteose Peptone, Tryptose, and Yeast Extract provide nitrogenous compounds, carbohydrates, vitamins, and minerals. Lactose is the fermentable carbohydrate. Neutral Red is the pH indicator that shifts to red upon medium acidification due to Lactose fermentation. Sodium Chloride maintains the osmotic balance and Agar is the gelifying agent.