Which of the following is the medium used for Vibrio cholerae?
**Core Concept**
The underlying principle being tested is the isolation and cultivation of **Vibrio cholerae**, a gram-negative bacterium that causes cholera. This requires a specific medium that supports its growth. **TCBS (Thiosulfate-citrate-bile salts-sucrose) agar** is commonly used for this purpose.
**Why the Correct Answer is Right**
TCBS agar is selective and differential, allowing **Vibrio cholerae** to grow while inhibiting other enteric bacteria. The **bile salts** in the medium inhibit the growth of **Gram-positive** bacteria, while **thiosulfate** and **citrate** support the growth of **Vibrio** species.
**Why Each Wrong Option is Incorrect**
**Option A:** Incorrect because it does not support the growth of **Vibrio cholerae**.
**Option B:** Incorrect as it is not the preferred medium for **Vibrio** isolation.
**Option D:** Incorrect because it lacks the specific components required for **Vibrio** growth.
**Clinical Pearl / High-Yield Fact**
Remember that **TCBS agar** is essential for the isolation of **Vibrio cholerae** in stool samples, aiding in the diagnosis of cholera.
**Correct Answer:** D. TCBS agar.