The accidental discovery of the miracle drug penicillin/Discovery of penicillin by Alexander Fleming

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Alexander Fleming was a Scottish physician and microbiologist, in St Mary’s Hospital, London. Fleming served throughout World War I in the Royal Army Medical Corps. During this time, he witnessed the death of many soldiers from sepsis resulting from infected wounds. In those days, antiseptics were used to treat infected wounds. However, he observed that rather than curing, these antiseptics often worsened the injuries, killing more soldiers than the infection itself. This is because antiseptics were able to remove surface bacteria but failed to reach anaerobic bacteria in the deep wounds. In 1922, Fleming discovered lysozyme, an enzyme with weak antibacterial properties. However, the enzyme was effective only against a small number of non-harmful bacteria.
In September 1928, Fleming was investigating the properties of staphylococci, bacteria that cause boils, sore throats, and abscesses. He inoculated Petri dishes with staphylococcal culture and went on a vacation. Accidentally, an uncovered Petri dish sitting next to an open window became contaminated with mold spores. When Fleming came back from vacation, he observed that the zone around the mold was completely clear, as if the mold has secreted something that inhibited bacterial growth. Generally, in research this is considered as contamination and the contaminated plates will be discarded as they are of no use. Here, instead of discarding the plate, Fleming started thinking about the reason for bacterial death. It was an awesome observation that lead to the initiation of the antibiotic era. Fleming identified the mold as Penicillium. Later he discovered that, it was not the mold itself instead, some juice produced by the mold that killed the bacteria. He named the ‘mold juice’ as penicillin. It was effective against all Gram-positive pathogens.
Initially, the scientific community greeted his work with little enthusiasm. In addition, the ‘mold juice’ was unstable and difficult to isolate in large quantities. So the work was discontinued. But Fleming saved the mold and distributed that to many experts in the hope of making penicillin drug. After a long gap of almost 10 years, Howard Florey, Ernst Chain and Norman Heatley from Oxford University made a great contribution to turn penicillin from a laboratory curiosity into a life-saving drug. Just to carry out a program of animal experiments and clinical trials, the team needed to process up to 500 liters of mold filtrate and about 2000 liters of mold filtrate to treat a human. To achieve this, Heatley cultured the mold in a variety of vessels with a large surface area, including biscuit tins, bottles, milk churns, petrol cans and even bedpans. Eventually, a customized fermentation vessel was designed to hold the liquid. A team of “penicillin girls” was employed to inoculate and look after the fermentation process.
With enough crude penicillin powder, in 1940, Florey carried out animal experiments. He injected eight mice with a virulent strain of Streptococcus, and then injected four of them with penicillin. All untreated mice died whereas the penicillin-treated mice were healthy and alive showing that penicillin could protect mice against infection from deadly Streptococci. Later in 1941, a 43-year old policeman, Albert Alexander, became the first recipient of the Oxford penicillin. He had a cut on his face and had developed a life-threatening infection with huge abscesses affecting his eyes, face, and lungs. He initially showed signs of recovery but the supply of penicillin quickly ran out and Albert’s infection returned.
With their growing success, the team approached pharmaceutical industries in Great Britain for mass production of penicillin. However, they were unable to do so because of World War II commitments. Later the Oxford team approached the United States to scale up the production. The experts in the US used deep fermentation tanks to culture the mold. They also found that, the use of corn-steep liquor, a waste by-product of corn starch provides an excellent environment for mold growth with an increased yield of penicillin. In addition, the laboratory assistant Mary Hunt found a better strain of Penicillium from a rotting melon that yielded six times more penicillin than Fleming’s strain.
Later, Flory approached pharmaceutical companies such as Pfizer, Squibb, Abbot, and Merck for the mass production of penicillin, especially for war victims. Throughout history, the major killer in wars had been infection rather than battle injuries. Penicillin use has reduced the death rate from 18% in world war I to 1% in world war II.
Due to their great contribution to mankind, Fleming, Florey, and Chain were awarded the Nobel Prize in 1945, in Physiology or Medicine. Using discovery and production techniques similar to penicillin, researchers discovered many other antibiotics in the 1940s and 1950s.

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