One of the great advances made during the last century was the discovery of penicillin.which set the precedent for the creation of modern antibiotics, which enable us to deal with microbial diseases.

Although the vaccines come from the hand of Louis Pasteur, and the advances made by Robert KochThe truth was that at the beginning of the 20th century there were still many fatal diseases once contracted.

That is why penicillin, a substance capable of killing different types of bacteria, took on such an important role, since it made it possible to fight these microorganisms once they were already inside the human body.

Biography of Alexander Fleming

Alexander Fleming

For this reason, Alexander Flemingwho discovered this substance by mistake, has been considered one of the most important men of the last century, and that is why here we are going to talk about his life, marked by several military conflicts and a laborious scientific task.

First Years

Alexander Fleming was born on 6 August 1881 in Darvel, Scotland.. He grew up in a peasant family, which could only afford a rather rudimentary education, but the young Alexander knew how to make the most of it.

In 1894, at the age of thirteen, he moved to London with his stepbrother who practiced medicine there. While there, Alexander Fleming took two courses at the Polytechnic Institute.

Professional and military life

In 1900 he enlisted in the London Scottish Regiment to take part in the Second Boer War (1899-1902), however, he did not have the opportunity to get to fight because the war ended before he even embarked.

Thanks to the fact that at the age of twenty he received the money from an inheritance, young Fleming could afford to study medicine.

In 1903 he won a scholarship to study at St. Mary’s Hospital Medical School in Paddington. In 1906 he joined the team of Sir Almroth Wright, a pioneer in vaccination, which initiated a professional relationship that would last more than forty years.

In 1908 he graduated from the University of London, winning the gold medal for it.

Alexander Fleming continued to enlist in the regiment, which led him to participate in World War I (1914-1918) as an officer of the Royal Army Medical Corps stationed in France.

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He was appointed Professor of Bacteriology at the University of London, and in 1928 became Professor of Bacteriology, a position he would hold until 1948.

In 1951 he was elected rector of the University of Edinburgh, a position he held for three years.

Personal life and last years

In 1915, following the World War, Alexander Fleming married an experienced nurse, Irish Sarah Marion McElroy. They had only one common son, Robert Fleming, who became a family doctor.

Sadly, Sarah Marion passed away in 1949 and Alexander Fleming remarried, this time to a Greek doctor, Amalia Koutsouri-Vourekas, who worked at St. Mary’s in 1953.

Alexander Fleming died on 11 March 1955 in Londonbecause of a heart attack. He was buried in St. Paul’s Cathedral in the English capital.


While I was stationed in France, Alexander Fleming observed that many wounded soldiers died from infections in their wounds.s. Although some antiseptics were used to treat these lesions, they often made them worse, making the inevitable ending much more painful.

First investigations

Fleming found that disinfectants worked very well for eliminating pathogens on the skin, but were totally contraindicated for treating deeper lesions.

This was because the antiseptics of the time were very harmful to microorganisms found inside the human body.

Although Alexander Fleming was endorsed by Sir Almroth Wright, many war doctors continued to use aggressive antiseptics on soldiers’ wounds, despite being aware that the injuries were worsening.

At the end of World War I, Fleming returned to St. Mary’s Hospital, where he researched for bacteria. There he discovered that the nasal mucosa of a cold patient seemed to have an inhibitory effect on the spread of bacteria.

This is considered the first report on lysozyme, an enzyme present in body fluids with antibacterial capacity.. However, despite obtaining a lot of substance with this enzyme, extracted mainly from eggs, the antibacterial effect seemed to be reduced, only affecting bacteria that were already quite harmless.

An accidental discovery: penicillin

Alexander Fleming was not an ordained person and, although this quality might seem very inappropriate for a scientist, it was what allowed him to make his greatest discovery.

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While on vacation for a month in 1928, he neglected to leave some staphylococcus cultures in a corner of his lab. Fleming observed that one of the cultures had been contaminated by a fungus that had destroyed the bacteria around it.

After analyzing the fungus, he discovered that it belonged to the genus Penicillium and the substance it produced baptized it as penicillin in 1929.. It is curious that before giving it that name he chose to call it ‘mould juice’.

Fleming published his findings in the Journal of Experimental Pathologybut it didn’t get the attention it deserved.

Although the first studies of penicillin gave inconclusive results, over time the substance became a real salvation for many soldiers wounded in the approaching Second World War and began the age of antibiotics as we know them today.

Honors and awards

Since the discovery of penicillin was a real change in the treatment of infectious diseases, Alexander Fleming was awarded many prizes.

  • The laboratory where Fleming discovered penicillin is preserved, being the place where the Fleming Museum is located.
  • In 1944 he was ordained a knight by King George VI of the United Kingdom.
  • In 1945 Fleming, along with Florey and Chain, received the Nobel Prize in medicine.
  • In 1948 he received the Grand Cross of the Order of Alfonso X the Wise.

And these are just a few of all the awards and recognitions he received in life. After his death, he was widely remembered. His name cannot be missing from biology books when it comes to the immune system and disinfection.

In 1999, Time magazine ranked him among the 100 most important men of the 20th century.and at least three Swedish journals in 2000 considered penicillin the greatest discovery of the second millennium.

Bibliographic references

  • Elsevier (1964) Nobel Lectures, the Physiology or Medicine 1942-1962. Amsterdam, The Netherlands. Elsevier Publishing Company.
  • Rhodes, P. (1985) An Outline History of Medicine. London, United Kingdom. Butterworths
  • Brown, K. (2004) Penicillin Man: Alexander Fleming and the Antibiotic Revolution, Stroud, United Kingdom. Sutton.
  • Rowland, J. (1957) The Penicillin Man: the Story of Sir Alexander Fleming, Lutterworth, United Kingdom. Lutterworth Press.