Question:
Colistin is obtained from which of the following?
Colistin is obtained from which of the following?
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Colistin is polymyxin E, a polypeptide from a Bacillus species.
Updated On: Jun 24, 2026
- Bacteria
- Fungi
- Actinomycetes
- Herbs
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The Correct Option is A
Solution and Explanation
Step 1: Antibiotics are classified by their natural source. Fungi yield penicillin, cephalosporin and griseofulvin. Bacteria (especially Bacillus species) yield the polypeptide antibiotics. Actinomycetes (Streptomyces and similar) yield aminoglycosides, tetracyclines, chloramphenicol, macrolides and polyenes.
Step 2: Colistin is also called polymyxin E. It is a polypeptide antibiotic produced by a bacterium, Bacillus (Paenibacillus) polymyxa. So colistin is obtained from bacteria, making option a correct.
Step 3: It is not from fungi (those give the beta-lactams and griseofulvin) and not from actinomycetes (those give aminoglycosides, tetracyclines and macrolides). It is certainly not a herbal product. The other bacterially derived polypeptides in the same family are polymyxin B, bacitracin and tyrothricin.
Step 2: Colistin is also called polymyxin E. It is a polypeptide antibiotic produced by a bacterium, Bacillus (Paenibacillus) polymyxa. So colistin is obtained from bacteria, making option a correct.
Step 3: It is not from fungi (those give the beta-lactams and griseofulvin) and not from actinomycetes (those give aminoglycosides, tetracyclines and macrolides). It is certainly not a herbal product. The other bacterially derived polypeptides in the same family are polymyxin B, bacitracin and tyrothricin.
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