Discovery of Penicillin
An Accidental Discovery That Changed the World
Did you know that the first effective medication against bacterial infections was actually discovered by accident and is now one of the most widely used antibiotics in the world?
The discovery and development of penicillin ushered in an era of antibacterial treatment that has changed the course of medicine. Before its identification as a potential lifesaving drug, doctors were unable to effectively treat formerly life-threatening bacterial infections such as infective endocarditis, rheumatic fever, pneumonia, gonorrhea, and syphilis.
Today, we take for granted the effectiveness of modern antibiotics, which have helped lead to the eradication of certain diseases and extend the life expectancy of people all around the world.
Alexander Fleming, pictured in his laboratory, 1943.
In 1928, professor of bacteriology at St. Mary's Hospital in London, Alexander Fleming, returned to his laboratory from a summer vacation and noticed a growth that had developed in one of the petri dishes he was using to culture the Staphylococcus bacteria. The dish had been accidently left open, and Fleming observed it was contaminated by mold, which appeared to have produced a bacteria-free ring around itself.
Fleming concluded that the mold had inhibited the bacteria’s development by releasing a substance that had caused the bacterial cells to undergo lysis—a medical term that refers to the breaking down of a cell’s membrane.
Following further analysis, Fleming determined that the active substance released from the mold not just destroyed Staphylococcus bacteria but was also effective against a wide range of harmful microorganisms, such as those that cause meningitis and diphtheria. Fleming observed that the active substance was a type of Penicillium mold and named it penicillin.
Chemical structure of the Penicillin core.
The professor established that the Penicillium mold was capable of killing bacteria harmful to humans and that it was suitable to use as an antibiotic against bacterial infection. However, Fleming’s attempts to isolate pure penicillin from the mold ended in failure.
In June 1929, Fleming published his findings in the British Journal of Experimental Pathology, but the potential therapeutic benefits of penicillin were not fully appreciated by the medical community at the time.
Fleming continued to show an interest in the development of penicillin, but because of the difficulties associated with isolating the antibiotic agent, he turned his attentions to other areas of bacteriology.
It wasn’t until 1939 that Fleming’s findings were taken to the next stage of development, when Oxford University researchers Howard Florey and Ernst Chain successfully extracted the active ingredient from Penicillium mold and scientifically proved that penicillin could be used to cure bacterial infections in mice.
By 1940, the researchers had developed a method of mass production, and Howard Florey travelled to the United States to work with pharmaceutical companies in an effort to produce penicillin on a large scale.
Despite the difficulties associated with the increasing yield of penicillin, US laboratories were able to refine the production process and ensure the antibiotic was ready for large-scale production by March 1944.
A poster attached to a curbside mailbox offering advice to World War II servicemen: Penicillin cures gonorrhea in 4 hours, 1944.
The dedication of the chemists and manufacturers in the United States ensured that penicillin was available to treat wounded British and American soldiers during the D-Day landings in Normandy in June 1944.
Today, the antibiotic and its derivatives continue to be used around the world to treat a wide range of infections.
“One sometimes finds what one is not looking for.” – Alexander Fleming
“I have been trying to point out that in our lives chance may have an astonishing influence and, if I may offer advice to the young laboratory worker, it would be this – never to neglect an extraordinary appearance or happening.” – Alexander Fleming
“For the birth of something new, there has to be a happening. Newton saw an apple fall; James Watt watched a kettle boil; Roentgen fogged some photographic plates. And these people knew enough to translate ordinary happenings into something new…” – Alexander Fleming
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