Question

Which of the following antibiotics is/are isolated from Streptomyces spp.?

• A. Gentamicin
• B. Nystatin
• C. Polymyxins
• D. Tetracyclines

Hint:

Remember: Many antifungals and tetracyclines originate from {Streptomyces}, while aminoglycosides like gentamicin are from {Micromonospora}.

Answer 1

The Correct Option is B, D

Step 1: General background. The genus Streptomyces is the largest antibiotic-producing group of actinobacteria. Nearly two-thirds of naturally derived antibiotics come from these soil-dwelling bacteria. Step 2: Evaluate each option. (A) Gentamicin – Produced by Micromonospora, not Streptomyces. ❌ (B) Nystatin – Produced by Streptomyces noursei; widely used antifungal. ✔️ (C) Polymyxins – Derived from Paenibacillus polymyxa, not Streptomyces. ❌ (D) Tetracyclines – Produced by several Streptomyces spp. (e.g., S. aureofaciens). ✔️ Step 3: Conclusion. Therefore, Nystatin (B) and Tetracyclines (D) are correct.