In September 1928, the bacteriologist Alexander Fleming returned to his London lab after a holiday to find a mess. His lab was famously untidy, and on one of his glass Petri dishes, something was wrong. He had been growing Staphylococcus bacteria, but a blob of blue-green mold had contaminated the plate. Around the mold, there was a clear, bacteria-free circle. The mold appeared to be dissolving the deadly germs. Fleming later recalled that he found the sight simply ‘funny.’ He had stumbled upon a mold that could kill bacteria, a discovery that would launch the age of antibiotics and change medicine forever. But how could this 'mold juice' be turned into a weapon for fighting disease?
The Discovery of Penicillin
How Alexander Fleming's 1928 mould observation became a usable drug through the Oxford team's work and American mass production, in time for D-Day and the start of the antibiotic era.
Chapter 1
A Funny Thing Happened
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Frequently Asked Questions
Who actually discovered penicillin?
Alexander Fleming, a Scottish bacteriologist, is credited with the discovery in 1928. He noticed a mold, Penicillium rubens, killing bacteria in a Petri dish at his London laboratory.
If Fleming discovered it, why did other scientists win the Nobel Prize too?
Fleming discovered the mold's effect, but he couldn't turn it into a stable drug. A team at Oxford University, led by Howard Florey and Ernst Chain, successfully purified penicillin into a usable powder and proved it worked in the 1940s. All three shared the 1945 Nobel Prize for their combined efforts.
How does penicillin kill bacteria?
Penicillin works by attacking the cell wall of bacteria. It prevents the bacteria from building and maintaining this protective layer. Without a stable wall, the bacterium cannot survive and bursts under its own internal pressure.
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