Testing and Producing Antibiotics

Testing. Every year, scientists test thousands of natural and chemi­cally modified microbial substances for potential use as antibiotics. First, these substances are tested against harmful microbes or cancer cells that have been grown either in test tubes or on laboratory plates.

A substance that shows strong antibiotic activity against patho­genic microbes or cancer cells is tested extensively in laboratory ani­mals. Then, if it produces no harmful effects in the animals, the anti­biotic is tested in human beings. In the United States, human testing must be approved by the Food and Drug Administration (FDA). If the drug proves to be safer and more effective than antibiotics already being used, it is submitted for approval to the FDA. Finally, if the FDA approves the antibiotic, drug firms begin to produce it commer­cially.

Antibiotics production involves several steps. First, cultures of the antibiotic-producing microbes are grown in flasks and then transferred to huge fermentation vats. The microbes multiply rapidly in the vats because the environment is controlled to stimulate their growth. After fermentation, the antibiotic substance is extracted from the culture and purified.

Some natural antibiotic substances are modified chemically to produce semisynthetic antibiotics. Many such drugs are more effective than the natural antibiotics from which they came.

Drug companies conduct special tests on antibiotics during and after production to ensure their quality. Finally, the purified antibiotic substances are made into pills, liquids, and ointments for medical use.

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