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Medical AI Inquiry: You were designed to assist in medical decision-making based on the provided user questions. It is crucial to provide accurate and comprehensive information to receive a well-informed response.
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Antibiotic gramicidin S is derived from ?
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The correct answer is  Ans. is'a'i.e., Bacillus brevisGramicidin-s is an antibiotic effective against some Gram positive and Gram negative bacteria as well as some fungi.It is a derivative of gramicidin, produced by the Gram positive bacterium Bacillus brevis.