## **Core Concept**
Streptomycin is an aminoglycoside antibiotic that works by inhibiting bacterial protein synthesis. It is primarily used to treat various bacterial infections, particularly those caused by Gram-negative bacteria. Its effectiveness is notable against certain specific pathogens.

## **Why the Correct Answer is Right**
The correct answer, **Plague**, is a condition caused by *Yersinia pestis*, a bacterium against which streptomycin is effective. Streptomycin disrupts bacterial protein synthesis by binding to the 30S subunit of the bacterial ribosome, which ultimately leads to the death of the bacterial cells. This mechanism makes it useful in treating infections such as plague.

## **Why Each Wrong Option is Incorrect**
- **Option A: Tuberculosis** - While streptomycin was historically used in the treatment of tuberculosis, especially in cases of drug-resistant TB, it is not the first-line treatment today due to its ototoxicity and nephrotoxicity. First-line antitubercular drugs are preferred.
- **Option B: Brucellosis** - Brucellosis is typically treated with doxycycline and rifampicin. Streptomycin can be used in combination with other antibiotics for certain bacterial infections but is not the primary choice for brucellosis.
- **Option C: Tularemia** - Tularemia, caused by *Francisella tularensis*, is usually treated with streptomycin or doxycycline, but the question asks for a more specific indication.

## **Clinical Pearl / High-Yield Fact**
A key point to remember is that streptomycin is particularly useful in treating **plague** and can also be used for **tularemia**. Its use in tuberculosis is limited due to toxicity and the availability of more effective drugs.

## **Correct Answer:** D. Plague