Alexander Fleming

Alexander Fleming was a Scottish physician and bacteriologist who in 1928 noticed that a mould growing on a culture plate in his London laboratory was killing the bacteria around it. The substance it produced, which he named penicillin, became the first antibiotic. Turning it into a usable medicine took the work of others, chiefly a team at Oxford, but Fleming's observation opened the age of antibiotics, and in 1945 he received a share of the Nobel Prize in Physiology or Medicine for it.

Fleming was born on 6 August 1881 at Lochfield, a farm near Darvel in Ayrshire, the son of a farmer who died when Alexander was seven. After village schools and Kilmarnock Academy he moved to London and spent four years as a clerk in a shipping office. A legacy from an uncle allowed him to follow his elder brother Tom into medicine, and in 1901 he entered St Mary's Hospital Medical School, Paddington, qualifying with distinction in 1906.

After qualifying he joined the research department under Sir Almroth Wright, a pioneer of vaccine therapy and immunology.

During World War I Fleming served as an officer in the Royal Army Medical Corps, working with Wright's team at a military hospital in Boulogne-sur-Mer in France. He watched many soldiers die of infected wounds and concluded that the antiseptics then in use often did more harm than good, since they failed to reach bacteria deep in a wound while damaging the body's own defences. He set out his evidence in The Lancet in 1917.

Back at St Mary's, in late 1921 he found that mucus from his own nose dissolved bacteria on a culture plate. He named the active substance lysozyme in 1922. It proved to be part of the body's natural defences, though it was too weak against dangerous bacteria to be useful as a drug.

On 3 September 1928, returning from a family holiday, he found that one of his plates of staphylococci had been contaminated by a mould, and that the bacteria near it had died. The mould was a species of Penicillium, which was later traced to a colleague's laboratory on the floor below. Fleming showed that broth from it killed many bacteria that cause diseases such as scarlet fever, pneumonia, meningitis and diphtheria, and on 7 March 1929 he named the substance penicillin.

His 1929 paper attracted little interest, chiefly because nobody could purify or produce penicillin in quantity. Fleming kept the mould alive and continued experimenting through the 1930s. The breakthrough came in Oxford, where Howard Florey, Ernst Chain, Norman Heatley and their colleagues purified a stable form in 1940 and tested it successfully.

In August 1942 Fleming used an Oxford sample to save a man dying of meningitis at St Mary's, and the case made headlines. With World War II under way, British and American production was expanded rapidly, and by D-Day in 1944 there was enough penicillin to treat all wounded Allied troops. Press coverage gave Fleming most of the credit, a distortion he himself called the Fleming myth. He was knighted in 1944 and shared the 1945 Nobel Prize with Florey and Chain.

Fleming was among the first to warn that bacteria could become resistant if penicillin was taken in doses too small or for too short a time. In his Nobel lecture he cautioned that the ignorant man might easily underdose himself and so breed resistant microbes.

He married the nurse Sarah McElroy in 1915; their only child, Robert, became a doctor. After her death in 1949 he married his Greek colleague Amalia Koutsouri-Vourekas in 1953. Fleming died of a heart attack at his London home on 11 March 1955, and his ashes were buried in St Paul's Cathedral.

Fleming spent his career in London, the capital of the United Kingdom. Our 1914 map shows Europe on the eve of the war in which he served, and the 1930 and 1945 maps frame the years from his discovery to his Nobel Prize.