Inoculation of the patient's feces on Endo medium

Inoculation of the patient's feces on Endo medium, followed by incubation in a thermostat, the growth of S-type colonies with various sizes and colors was obtained. Some colonies were large, red; others are small, colorless. 1. What types of microorganisms could be in the test material? 2. To what group of environments does the above environment belong? 3. What are some more nutrient media used for these purposes?