How a moldy accident changed the course of human medicine
In short: In 1928, Alexander Fleming noticed something strange: bacteria refused to grow near a patch of mold. This accidental observation led to the discovery of penicillin, the world's first antibiotic. It transformed medicine from a gamble against infection into a tool that has saved millions of lives.
The discovery occurred when Fleming observed that colonies of Staphylococcus aureus failed to grow in areas contaminated by the green mold Penicillium notatum. He identified that the mold produced a substance capable of killing many common bacteria that infect humans. Although Fleming initially separated the compound, Howard Florey, an Australian pathologist, and Ernst Boris Chain, a British biochemist, did not manage to refine penicillin for medical treatment until the late 1930s. By 1941, an injectable form became available for patients.
Penicillin works by attacking the structural integrity of the bacteria. By blocking enzymes that build cell walls in growing microbes and triggering different enzymes to destroy current barriers, the drug functions effectively. This targeted destruction allows the drug to eliminate bacteria without harming the host's cells. Because different species of Penicillium mold produce different varieties, scientists can now synthesize 'semisynthetic' penicillins by altering the chemical structure of 6-aminopenicillanic acid.
Modern medicine differentiates between types based on stability. For example, penicillin G is broken down by stomach acid and must be administered via intramuscular injection. In contrast, penicillin V (phenoxymethylpenicillin) is acid-resistant and can be taken orally as tablets or liquids. While it is commonly used to treat ear, throat, and skin infections, it is also used as a preventative measure for individuals with specific conditions, such as sickle cell disease or those who have had their spleen removed.
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Sources
- Summary by Intellect · source: Penicillin | Microorganisms | Biology | FuseSchool
- Also: Penicillin | Discovery, History, Uses, Types, Side Effects, & Facts | Britannica
- Also: www.nhs.uk — Phenoxymethylpenicillin: antibiotic for bacterial infections
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