Alexander Fleming


Alexander Fleming : biography

6 August 1881 – 11 March 1955

Fleming published his discovery in 1929, in the British Journal of Experimental Pathology, but little attention was paid to his article. Fleming continued his investigations, but found that cultivating penicillium was quite difficult, and that after having grown the mould, it was even more difficult to isolate the antibiotic agent. Fleming’s impression was that because of the problem of producing it in quantity, and because its action appeared to be rather slow, penicillin would not be important in treating infection. Fleming also became convinced that penicillin would not last long enough in the human body (in vivo) to kill bacteria effectively. Many clinical tests were inconclusive, probably because it had been used as a surface antiseptic. In the 1930s, Fleming’s trials occasionally showed more promise, and he continued, until 1940, to try to interest a chemist skilled enough to further refine usable penicillin. Fleming finally abandoned penicillin, and not long after he did, Howard Florey and Ernst Boris Chain at the Radcliffe Infirmary in Oxford took up researching and mass-producing it, with funds from the U.S. and British governments. They started mass production after the bombing of Pearl Harbor. By D-Day in 1944, enough penicillin had been produced to treat all the wounded in the Allied forces.

Purification and stabilisation

In Oxford, Ernst Boris Chain and Edward Abraham dicovered how to isolate and concentrate penicillin. Abraham was the first to propose the correct structure of penicillin. in October 1943 Abraham proposed a molecular structure which included a cyclic formation containing three carbon atoms and one nitrogen atom, the β-lactam ring, not then known in natural products. This structure was not immediately published due to the restrictions of wartime secrecy, and was initially strongly disputed, by Sir Robert Robinson among others, but it was finally confirmed in 1945 by Dorothy Crowfoot Hodgkin using X-ray analysis." Oxford Dictionary of National Biography; "Abraham, Sir Edward Penley" Shortly after the team published its first results in 1940, Fleming telephoned Howard Florey, Chain’s head of department, to say that he would be visiting within the next few days. When Chain heard that he was coming, he remarked "Good God! I thought he was dead."

Norman Heatley suggested transferring the active ingredient of penicillin back into water by changing its acidity. This produced enough of the drug to begin testing on animals. There were many more people involved in the Oxford team, and at one point the entire Dunn School was involved in its production.

After the team had developed a method of purifying penicillin to an effective first stable form in 1940, several clinical trials ensued, and their amazing success inspired the team to develop methods for mass production and mass distribution in 1945.

Fleming was modest about his part in the development of penicillin, describing his fame as the "Fleming Myth" and he praised Florey and Chain for transforming the laboratory curiosity into a practical drug. Fleming was the first to discover the properties of the active substance, giving him the privilege of naming it: penicillin. He also kept, grew, and distributed the original mould for twelve years, and continued until 1940 to try to get help from any chemist who had enough skill to make penicillin. But Sir Henry Harris said in 1998: "Without Fleming, no Chain; without Chain, no Florey; without Florey, no Heatley; without Heatley, no penicillin."Henry Harris, Howard Florey and the development of penicillin, a lecture given on 29 September 1998, at the Florey Centenary, 1898–1998, Sir William Dunn School of Pathology, Oxford University (sound recording)


Fleming’s accidental discovery and isolation of penicillin in September 1928 marks the start of modern antibiotics. Before that, several scientists had published or pointed out that mould or penicillium sp. were able to inhibit bacterial growth, and even to cure bacterial infections in animal (Ernest Duchesne in 1897 in his thesis "Contribution to the study of vital competition in micro-organisms: antagonism between moulds and microbes", or also Clodomiro Picado Twight whose work at Institut Pasteur in 1923 on the inhibiting action of fungi of the "Penicillin sp" genre in the growth of staphylococci drew little interest from the direction of the Institut at the time). Fleming was the first to push these studies further by isolating the penicillin, and by being motivated enough to promote his discovery at a larger scale. Fleming also discovered very early that bacteria developed antibiotic resistance whenever too little penicillin was used or when it was used for too short a period. Almroth Wright had predicted antibiotic resistance even before it was noticed during experiments. Fleming cautioned about the use of penicillin in his many speeches around the world. He cautioned not to use penicillin unless there was a properly diagnosed reason for it to be used, and that if it were used, never to use too little, or for too short a period, since these are the circumstances under which bacterial resistance to antibiotics develops.