Corynebacterium diphtheriae can be grown within 6-8 hour on
**Core Concept**
Corynebacterium diphtheriae is a Gram-positive, rod-shaped bacterium that causes diphtheria. The growth of this bacterium is typically observed on selective media, which inhibits the growth of other bacteria.
**Why the Correct Answer is Right**
Corynebacterium diphtheriae can be grown on Tellurite agar within 6-8 hours. The tellurite in the agar inhibits the growth of most other bacteria, allowing C. diphtheriae to grow and form characteristic colonies. The growth of C. diphtheriae on Tellurite agar is due to its ability to reduce tellurite to metallic tellurium, which is visible as a dark deposit on the surface of the colonies.
**Why Each Wrong Option is Incorrect**
* **Option A:** Loeffler's serum slope is used for the growth of C. diphtheriae, but it does not selectively inhibit the growth of other bacteria and therefore is not the correct answer.
* **Option B:** Blood agar is a general-purpose medium that supports the growth of many types of bacteria, including those that can cause diphtheria. However, it does not selectively inhibit the growth of other bacteria and therefore is not the correct answer.
* **Option D:** MacConkey agar is a selective medium that is used to differentiate between lactose-fermenting and non-lactose-fermenting bacteria. It is not used for the growth of C. diphtheriae.
**Clinical Pearl / High-Yield Fact**
Corynebacterium diphtheriae can be differentiated from other bacteria by its ability to produce a characteristic "metachromatic" granule, which is a type of inclusion body that can be stained with specific dyes. This is an important diagnostic feature that can be used to identify C. diphtheriae in clinical specimens.
**Correct Answer:** C. Tellurite agar.