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Monday 23 January 2017

Penicillin

While working on the influenza virus at St Mary's Hospital in London on September 28, 1928, Alexander Fleming observed that mold, which had developed accidentally on a germ-colored glass plate that he had left in the sink, had created a bacteria-free circle around itself. After further experiments the Scottish biologist and pharmacologist  found that a mold culture, Penicillium notatum, was releasing a substance that inhibited bacterial growth, even when diluted 800 times. He named the active substance penicillin.

Fleming's paper describing this phenomenon mentioned the possibility of this substance being a treatment for eye infections. However he was unable to obtain penicillin in a sufficiently pure form to produce reliable results in infected patients, and he became convinced that it could not last long enough in the human body to kill disease producing bacteria. Fleming abandoned this particular research in 1931.

In the 1930s and early 1940s, penicillin was so precious that it was re-extracted from the urine of patients to conserve every last bit of it.

Penicillin was originally called ‘mold juice’.

Sample of penicillin mould presented by Alexander Fleming to Douglas Macleod, 1935. Science Museum London / Science and Society Picture Library

In 1939 René Dubos, a French-American bacteriologist isolated tyrothricin, the first commercially produced antibiotic. His pioneering work stimulated others to look at Fleming’s work on penicillin, including in 1940 a team of Oxford research scientists led by an Australian pathologist Howard Florey and including the German-British biochemist Ernst Chain. They proved that penicillin could fight infections in people, after treating PC Albert Alexander on February 12, 1941 for a dangerous infection caused by a scratch from a thorn. The results were excellent but the team ran out of penicillin and he died.

Aware of the need of a fungus that could yield sufficient penicillin reliably, Florey and Chain  searched for a more productive species. Mary Hunt, a lab assistant, came across a cantaloupe with a golden mold, P. chrysogenum. All penicillin is effectively descended from Mary Hunt’s cantaloupe.

Florey and Chain's work resulted in the mass producing of the drug. Penicillin saved the lives of countless soldiers during World War II, who would have died from their wounds in previous wars.

Florey and Chain shared the 1945 Nobel Prize in medicine with Fleming for their work. Fleming humbly responded to receiving the award  “Nature makes penicillin; I just found it."


Fleming ever made any money from his discovery. He had no wish to do so.

Florey and Chain's work is estimated to have saved up to 200,000,000 lives.

Almost a century after the discovery of penicillin, bacterial infections continue to kill about 700,000 people each year.

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