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Penicillin discovery

the world’s first antibiotic drug London,

Alexander Fleming looking into a microscope.
Alexander Fleming in his lab, December 1943. NMeM/Daily Herald Archive/SSPL

The first antibiotic drug was revealed when Alexander Fleming (1881-1955), a bacteriologist working at St Mary’s Medical School in London, noticed a bacteria-free circle around a mould in a culture dish used to grow microbes. 

Through further experiments Fleming realised that the mould was preventing the growth of the bacteria. He managed to examine the microbe-controlling characteristics of the yellow liquid produced by the mould, but did not isolate the active ingredient. At the time Fleming had no idea how important this discovery would be. 

A decade later a team at Oxford including Ernst Chain (1906-79), Norman Heatley (1911-2004) and Howard Florey (1898-1968) extracted a powerful drug from the mould. Within a few years scientists in the United States developed a new mould, along with new methods of growing it and extracting the drug. By 1944 it was being mass-produced. 

The drug, which was called penicillin, proved very effective in the treatment of infected wounds and against syphilis and pneumonia. This was the first widely used antibiotic. Closely related drugs are still used all over the world today. Bacteria however are constantly evolving in response to the use of antibiotics, and resistance to penicillin was noted within a few years of its introduction. 

Science Museum

St Mary's Medical School, London
Key Individuals
Alexander Fleming, Howard Florey, Norman Heatley, Ernst Chain,