Alexander Fleming and his experiments
Alexander Fleming, working as a bacteriologist in St Mary’s Hospital, London, was searching for ways to destroy the bacteria that attack the human body.
Fleming, who went home on vacation, had forgotten to keep his petri dish, containing the Staphylococcus bacteria in the incubator before leaving the laboratory. When he returned to the lab after his vacation, he noticed a greenish-blue mould on one side of the petri dish. He also noticed that the area around the mould inhibited the growth of the bacteria.
The mould was later identified as a rare strain of Penicillium Notatum. Thus, penicillin, the discovery which changed the history of medical science.
Penicillin is used to treat certain kinds of bacterial infections. Even though Alexander Fleming discovered penicillin, he could not describe its therapeutic benefits. His findings were published in the British Journal of Experimental Pathology in 1929.
Howard Florey and development of penicillin as a clinical drug
Alexander Fleming’s article on penicillin laid the groundwork for scientists in Oxford to begin research on antimicrobials. In 1939, Howard Florey, a professor at Oxford, together with his colleague Ernst Chain, decided to develop a method to isolate the compound. It was the time when World War II was making research activities difficult.
Norman Heatley, a young fungal expert in Florey’s team, worked on growing penicillin supplement in large quantities and extracted huge volumes of filtrates from the production line.
Carrying out experiments on animals and subsequent clinical trials needed a large amount of mould filtrate. Howard Florey and Ernst Chain started growing moulds in vessels such as bedpans, milk churns, and food tins. Later, they designed a customised fermentation vessel to make the process easier.
Norman Heatley, a young fungal expert in Florey’s team, worked on growing penicillin supplement in large quantities and extracted huge volumes of filtrates from the production line. Edward Abraham, another biochemist who was appointed to speed up the production process, successfully purified penicillin from the extracts prior to the trials.
Howard Florey, who oversaw the experiments in animals, and his team injected eight mice with the virulent streptococcus strain. Afterwards, four out of eight mice were injected with penicillin, and the others were left untreated. The next morning, those mice that did not receive the treatment were found dead, and the treated mice were alive.
In 1940, the researchers published their results in the British medical journal, The Lancet, describing the production, purification and experimental use of penicillin. They proved that penicillin has the potential to protect animals infected with bacteria such as Streptococcus Pyogenes, Staphylococcus Aureus, and Clostridium Septique.
Clinical experiments with penicillin started in February 1941, when penicillin was injected in an Oxford policeman who was exhibiting serious infections. His condition significantly improved within 24 hours. However, there wasn’t enough of the drug available to bring him back to life.
Between 1941 and 1942, Howard Florey and his team conducted clinical trials in 170 people. All these experiments proved that penicillin could be used to treat infections without much side effects.
A very large amount of penicillin was needed for extensive clinical trials to confirm the results. The companies in Great Britain were unable to produce penicillin in large quantities because of the ongoing World War II. Howard Florey realised that producing penicillin in large quantities was not possible in Great Britain as the chemical industry was fully immersed in the war, so he decided to seek help from companies and institutions in the United States of America.
Alexander Fleming, Howard Florey and Ernst Chain were awarded the Nobel Prize in Medicine in 1945.
At that time, the US was not involved directly in the war. Howard Florey and his team travelled to the US with the help of the Rockefeller Foundation to explore whether American pharmaceutical companies could produce penicillin in large quantities. They were then introduced to Robert Thom, a leading mycologist at the US Department of Agriculture, and eventually to the department’s Northern Regional Research Laboratory (NRRL) in Illinois, which had the expertise in the required fermentation process. This partnership was crucial as the NRRL contributed considerably to the large-scale production of penicillin.
In 1946, penicillin became available for general use for the first time in the United Kingdom.
During World War II, penicillin was first used in military hospitals in Northern Africa. The use of penicillin was effective as it reduced infection in wounds, thereby reducing fatalities significantly. Bacterial infection had claimed the lives of thousands of soldiers during World War I.
Alexander Fleming, Howard Florey and Ernst Chain were awarded the Nobel Prize in Medicine in 1945.
In 1946, penicillin became available for general use for the first time in the United Kingdom.
The discovery and development of penicillin by Fleming, Florey and Chain started a new era in medical science. Penicillin came to be called the ‘miracle drug’ because it cured thousands of people who would have otherwise died.
Antibiotics hold a significant place in the history of modern medicine. However, antibiotics are the only types of drugs that lose its efficiency with large-scale use because bacteria start to develop resistance to the antibiotics. This is why we are now struggling with resistant bacteria.
Drug companies have grown reluctant in developing new kinds of antibiotics because it can take 10-15 years and billions of dollars to develop new antibiotics. This is the reason why no new classes of antibiotics have been discovered since the 1980s. The antibiotics that are being developed now are only variations of drugs discovered before.
Now put on your thinking hats and think about the following questions for a couple of minutes.
As a teacher, how do you describe the term "antibiotics" to your students?
Can you think of the ways in which the discovery of penicillin transformed medical science?
Can you think of reasons why antibiotics lose their effectiveness over the years?
Write down your thoughts and discuss them with your students, children and your colleagues. Listen to their views and compare them with your own. As you listen to others, note how similar or different your views are to others’.
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Happy Teaching!
Discovery and development of ‘miracle drug’ penicillin