Penicillin: How a mistake led to a medical breakthrough
- Tho Nguyen
- Jul 22, 2020
- 2 min read
Nowadays, penicillin is one of the most popular antibiotics, lining pharmaceutical shelves worldwide. However, a remarkable story lies behind this seemingly ordinary medicine. The discovery of penicillin drastically changed the world of medical science, providing doctors with the ability to combat deadly bacterial infections and saving countless lives. First stumbled upon in 1928, penicillin played a monumental role in World War II and has been healing patients ever since.
Although Sir Alexander Fleming is credited for this incredible discovery, one could argue that the story began with a forgotten lab procedure. Fleming was experimenting with the influenza virus at St. Mary’s Hospital in London. After returning from a two-week vacation, he found a mold growing on a contaminated staphylococcus plate. Upon further inspection, he observed that the mold stopped the growth of the staphylococci.
Sir Alexander Fleming, who first discovered penicillin mold.
Image Credits: Corbis via Getty Images
Dr. Howard Florey named the mold Penicillium notatum, and carried out a number of experiments on mice. Fifty mice were injected with streptococcus, and half were treated with penicillin. The mice treated with penicillin survived, while the untreated mice died. Florey then went on to experiment on humans, but faced difficult obstacles along the way.
Extracting enough pure penicillin was a challenging endeavor - it took 2,000 liters of the substance to treat just one patient. Florey began treating his first patient, Albert Alexander, in 1941. Sadly, there was not enough penicillin to continue treatment, and Albert passed away. Eventually, a new type of penicillin was able to be mass-produced for pure penicillin (Penicillium chrysogenum).
What had started out as an unusual discovery became a life-saving treatment. The death rate from pneumonia fell from 18% in WWI to 1% in WWII due to the distribution of penicillin. Previously lethal infections like meningitis, endocarditis, gonorrhea, syphilis, and strep throat were now easily treated.
Penicillin works by preventing bacteria from producing peptidoglycan, a molecule in the cell wall that gives it the strength to survive in the human body. Thus, the cell walls of bacteria are weakened, causing the bacteria to die and allowing recovery from infections.
Now, penicillin mold is grown in deep fermentation tanks, by adding sugar and other ingredients to help bolster production. Then, the product is separated from the mold before being purified for medicinal use.
The discovery of penicillin transformed the way people viewed medicine, and inspired other scientists to search for naturally occurring substances with antimicrobial activity. Soon, other antibiotics like streptomycin and tetracycline were being marketed for medicinal use. Thanks to Fleming, a host of fatal diseases were now curable. It would be quite difficult to imagine a world without antibiotics, where Fleming’s dirty lab plate was instead pristine. Sometimes, a mistake can point you in the right direction, after all.
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