Modified Thayer-martin medium is used for –
**Core Concept**
Modified Thayer-Martin medium is a selective agar medium used for the cultivation and isolation of Neisseria gonorrhoeae, a Gram-negative diplococcus that causes gonorrhea. This medium is designed to inhibit the growth of other bacteria while allowing N. gonorrhoeae to grow.
**Why the Correct Answer is Right**
The medium contains antibiotics such as vancomycin, colistin, and nystatin, which inhibit the growth of Gram-positive bacteria, Gram-positive cocci, and fungi, respectively. The addition of antibiotics and supplements such as hemin and nicotinamide adenine dinucleotide (NAD) helps to promote the growth of N. gonorrhoeae. The selective nature of this medium allows for the isolation of N. gonorrhoeae from clinical samples, facilitating its identification and diagnosis.
**Why Each Wrong Option is Incorrect**
**Option A:** Incorrect, as Thayer-Martin medium is not primarily used for the cultivation of Haemophilus influenzae.
**Option B:** Incorrect, as this medium is not specifically designed for the growth of Staphylococcus aureus.
**Option C:** Incorrect, as while Neisseria meningitidis can be isolated on Thayer-Martin medium, it is not the primary use of this medium.
**Clinical Pearl / High-Yield Fact**
Remember that Thayer-Martin medium is a selective medium, and its use is crucial for the isolation of N. gonorrhoeae from clinical samples. This is particularly important in the diagnosis of gonorrhea, a sexually transmitted infection that can cause significant morbidity if left untreated.
**Correct Answer: C. Neisseria gonorrhoeae**