A bacteriologist sneaks off on holiday without doing the washing-up

Carelessness and untidiness are not the sort of characteristics that most parents try to instil in their offspring. Rather they are apt to warn their children that these are the kind of traits that will inevitably lead to a life of dissipation or, at best, barely managed chaos. However, there are occasions when such habits can actually be advantageous. For example, the most famous happy accident in medical history occurred only because two exceedingly trivial details in a man’s life coincided, neither of which would have happened had it not been for an act of carelessness combined with a little devil-may-care untidiness.

The man in question was Alexander Fleming. Born in 1881 on a farm in Ayrshire, Fleming studied medicine and became a bacteriologist at St Mary’s Hospital in Paddington, West London. His research and lecturing were interrupted by World War I, during which he served as a captain in the Royal Army Medical Corps. Attending to wounded soldiers in hospitals just behind the lines in France, he witnessed many deaths due to infected wounds. Antiseptics – as pioneered by the surgeon Joseph Lister – were used extensively by British army doctors. However, Fleming noticed that while they were effective when used to treat superficial injuries, they killed more soldiers than they cured when applied to deeper wounds. After the war he returned to St Mary’s with a renewed vigour, determined to find some way of defeating the bacteria that infected these more serious traumas.

He thought he had made a breakthrough in 1923, when his tests established that nasal mucus slowed down the growth of bacteria. The enzyme responsible, lysozyme, can also be found in saliva, tears, hair and skin as well as in egg whites. It was a previously unknown enzyme and its discovery put Fleming’s name on the map. Unfortunately, it was not the remedy he had hoped for, because it proved effective only against bacteria that were harmless.

It was five years later, when Fleming was working on the influenza virus, that he took the huge step forward for which he had been striving so long. Ironically, it occurred because he went on a month’s holiday (not a fortnight’s break, as is often erroneously reported). Rather than washing up all his petri dishes (he had been growing the staphylococcus bacteria to use in his experiments) and tidying them away in a cupboard, he left them piled up in the sink. Furthermore, no doubt demob-happy at the thought of his break at his family’s country house near Newmarket in Suffolk, he did not notice that a window to the street had been left open.

When he came back, on Friday 28 September 1928, he went to the sink to start on the task he should properly have carried out a month beforehand. He might well have cleaned everything up and started back on his work, but he noticed something curious in one of the petri dishes in which he had been growing the bacteria: a sort of blue-green mould had established itself. While Fleming had been sunning himself in Suffolk, it had been busily expanding across the glass, creating a halo that was entirely free of the staphylococcus bacteria. The mould, which had blown in through the window by chance, was Penicillium notatum.

This did not constitute the discovery of penicillin, as is often reported. Although it’s true that Fleming did coin the word, the penicillium mould had been identified at least 40 years beforehand. Joseph Lister himself had experimented with it on humans with some success, although there’s no evidence that Fleming knew about his fellow scientist’s research. What’s more, although Fleming published his own research the following year and also achieved some favourable outcomes when treating patients, he found the mould very difficult to cultivate in any quantity and his research into penicillin became somewhat fitful.

It did not help that he was not a great communicator and so had found it difficult to enthuse others with his work. By 1940 he had given up altogether. Thankfully, an Australian pharmacologist called Howard Florey at Oxford University had come across Fleming’s research and decided to carry out his own investigations. He put together a team of scientists that included Ernst Chain – a German Jew who was expert in pathology and had fled Hitler’s Reich – and Norman Heatley, who was greatly skilled in the micro-analysis of organic substances. Florey’s team developed penicillin further, purifying it to such an extent that in 1940 they were able to cure infections in mice. Like Fleming, they also found it difficult to produce the drug in any quantity. Although they had come up with a method of mass-producing it in the laboratory, they still couldn’t manage the sort of yields that would make its use practicable.

Successful trials followed in 1941 at Oxford’s Radcliffe Infirmary, but these were still very small scale, so Florey and Heatley crossed the Atlantic to attempt to talk pharmaceutical companies into manufacturing the drug. Even though their offer was taken up, by the summer of 1942 there had only been enough penicillin created in the US to treat ten patients. It took a chemical engineer called Margaret Hutchinson Rousseau to break the logjam, developing a process of deep-tank fermentation using corn steep liquor. In 1943, the Northern Regional Research Laboratory at Peoria, Illinois, instigated a global search for the best mould to use in the fermentation process. As it happened, the ideal candidate proved to be close at hand – a rotting cantaloupe melon found in a Peoria market was found to contain an excellent mould for the job. By the time of the Normandy landings, 2.3 million doses of penicillin had been prepared. By the end of the war, this figure had risen to hundreds of billions of doses.

The introduction of penicillin by the Allies in the latter stages of World War II was very effective in combatting septicaemia and gangrene, both of which could turn a run-of-the-mill wound into a fatal one. The Axis forces did not have access to the drug and, as a consequence, the survival and recovery rates of the latter’s injured troops was markedly lower. In this way, the open window and the dirty petri dish back in 1928 made their contribution to the war effort. Penicillin was also found to work extremely well against bacterial diseases such as typhoid and tuberculosis, which were rife at the time.

Given the massive and immediate impact penicillin had, it’s unsurprising that Fleming, Florey and Chain did not have long to wait for their efforts to be recognised. The three were jointly awarded the Nobel Prize in Physiology or Medicine in 1945. Fleming and Florey would both go on to be knighted.

The wonder drug that saves millions of lives around the world each year is today faced with new challenges. It was as early as the late 1940s that reports started to come in of microbes that had become resistant to its effects. Today, so-called superbugs such as MRSA are proving very difficult to counteract. The work of modifying penicillin (and other antibiotics) continues apace in a grim game of catch-up.

The very mould that Fleming found that day in 1928 still exists, on account of the fact that he took the trouble to put it in a glass frame and label it. It was sold at auction in London in March 2017 for £24,375. Meanwhile, the open window at St Mary’s through which the mould blithely sailed one September day is commemorated by a purple plaque two storeys below.