Choose the correct answer from the options given below :

• (1) (A)-(IV), (B)-(III), (C)-(II), (D)-(I)
• (2) (A)-(I), (B)-(II), (C)-(IV), (D)-(III)
• (3) (A)-(IV), (B)-(I), (C)-(III), (D)-(II)
• (4) (A)-(I), (B)-(II), (C)-(III), (D)-(IV)

  Vancomycin targets Gram-positive bacteria and comes from Streptomyces orientalis, while bacitracin, streptomycin, and amphotericin derive from specific Bacillus and Streptomyces strains. The correct option matches each antibiotic to its microbial producer.

  Antibiotic Producers

  These antibiotics are secondary metabolites from soil microbes, used against bacterial or fungal infections.

  • Vancomycin (A): Produced by Streptomyces orientalis (IV).

  • Bacitracin (B): Produced by Bacillus subtilis (I).​

  • Streptomycin (C): Produced by Streptomyces griseus (III).​

  • Amphotericin (D): Produced by Streptomyces nodosus (II).​

  Option Analysis

  • Option (1): (A)-(IV), (B)-(III), (C)-(II), (D)-(I) wrong; bacitracin not griseus, streptomycin not nodosus.

  • Option (2): (A)-(I), (B)-(II), (C)-(IV), (D)-(III) incorrect; vancomycin not subtilis, streptomycin not orientalis.​

  • Option (3): (A)-(IV), (B)-(I), (C)-(III), (D)-(II) correct; aligns with established producers.

  • Option (4): (A)-(I), (B)-(II), (C)-(III), (D)-(IV) fails; vancomycin/bacitracin swapped, amphotericin not orientalis.​

  Correct answer: (3).

  Antibiotic producers matching questions test knowledge of microbial sources like Streptomyces orientalis for Vancomycin, Bacillus subtilis for Bacitracin, Streptomyces griseus for Streptomycin, and Streptomyces nodosus for Amphotericin, vital for pharmacology and microbiology exams.

  Microbial Sources Overview

  Streptomycetes dominate antibiotic production via polyketide/non-ribosomal pathways; Bacillus yields peptides like bacitracin.

  Correct Matching Table

  Antibiotic (List I)	Producer (List II)	Target
  (A) Vancomycin	(IV) Streptomyces orientalis	Gram+ bacteria
  (B) Bacitracin	(I) Bacillus subtilis	Gram+ cell walls ​
  (C) Streptomycin	(III) Streptomyces griseus	Protein synthesis ​
  (D) Amphotericin	(II) Streptomyces nodosus	Fungal membranes ​

  Options Explained

  Options 1/4 mismatch bacitracin/streptomycin; 2 confuses vancomycin/streptomycin; 3 matches literature precisely. Note: Amycolatopsis orientalis (formerly Streptomyces orientalis) is standard for vancomycin in exams. For GATE prep, recall streptomycin’s TB role, amphotericin’s antifungal action.