Culture medium for Corynebacterium diphtheriae?
**Core Concept**
Corynebacterium diphtheriae is a Gram-positive, rod-shaped bacterium that causes diphtheria, a serious infectious disease. This bacterium requires specific nutrients for growth, which can be provided by a particular type of culture medium.
**Why the Correct Answer is Right**
Corynebacterium diphtheriae grows best on Loeffler's serum slope, a type of enriched culture medium that provides the necessary nutrients for its growth. This medium is enriched with serum, which provides the necessary nutrients, and a solid surface that allows the bacteria to adhere and grow. The bacteria grow rapidly on this medium and produce characteristic metachromatic granules, which are visible under a microscope.
**Why Each Wrong Option is Incorrect**
**Option A:** Blood agar is a general-purpose culture medium that is used to grow a wide range of bacteria, but it is not the specific medium required for Corynebacterium diphtheriae.
**Option B:** MacConkey agar is a selective medium used to differentiate between lactose-fermenting and non-lactose fermenting Gram-negative bacteria, and is not suitable for growing Corynebacterium diphtheriae.
**Option C:** Sabouraud dextrose agar is a medium used to grow fungi, and is not suitable for growing Corynebacterium diphtheriae.
**Clinical Pearl / High-Yield Fact**
Loeffler's serum slope is a classic example of an enriched culture medium that is used to grow fastidious bacteria like Corynebacterium diphtheriae. It is a high-yield fact that students should remember when attempting to culture this bacterium in the laboratory.
**Correct Answer:** C.