The penicillin mould accidentally grown by the physician and microbiologist Alexander Fleming in London in 1928 has had its genome sequenced for the first time.
Researchers from the United Kingdom used frozen samplings of Sir Fleming’s original strain of the fungus and compared them with their current, industrially used counterparts.
The sample of Sir Alexander Fleming’s strain they grew had been kept on ice in the culture collections at the Centre for Agriculture and Bioscience International, Oxfordshire and they discovered that the wild UK strain used a slightly different way to produce penicillin than the strains currently used to manufacture the antibiotic in the US.
The discoveries could offer new ways to improve the widescale production of the drug, which is used to treat a combination of bacterially derived infections.
Sir Alexander Fleming discovered the first known antibiotic when a mould of the genus Penicillium accidentally began growing in a Petri dish in his laboratory at the St Mary’s Hospital Medical School, which is today part of the Imperial College London.
He noticed that in a receptacle, which had been left uncovered near an open window, where it became contaminated by the mould, the Staphylococcus bacteria he had left cultivating during a break to Suffolk had died where the fungus had grown.
In contrast, Staphylococci colonies growing further away from the mould were untouched, an observation that led him to comment ‘That’s funny’.
Sir Alexander Fleming was awarded the 1945 Nobel Prize in Physiology and Medicine for his work on penicillin and antibiotics, along with colleagues Ernst Chain and Howard Florey.
Although Sir Alexander Fleming’s strain of the mould is famously referred to as the actual origin of penicillin, production of the antibiotic in the US quickly changed over to using a different type, one that grew on mouldy cantaloupes.
Furthermore, this naturally derived fungus went on to alter over time, as drug manufacturers artificially selected for strains that delivered higher volumes of penicillin and therefore proved to be more lucrative to use.
In their study, the researchers grew mould from an actual sample of Sir Alexander Fleming’s fungus that had been kept frozen in the culture collections of the Centre of Agriculture and Bioscience International.
Paper author and evolutionary biologist Timothy Barraclough of Imperial College London and the University of Oxford said that they initially set out to use Alexander Fleming’s fungus for some other experiments, but then discovered, to their astonishment, that no one had sequenced the genome of this original Penicillium, despite its documented importance to the field.
Professor Barraclough and associates concentrated in particular on two kinds of genes, those that encode for the enzymes that the fungus uses to produce penicillin, and those that regulate those enzymes, for instance by controlling their manufacture.
The team found that both Sir Alexander Fleming’s UK strain and those used industrially in the US had the same regulatory gene code, but the latter variants of the fungus had more compositions of the regulatory genes, allowing them to make more of the drug.
Furthermore, the researchers found that the genes that code for the penicillin producing enzymes were different between the strains isolated in the UK and the US. This, they said, shows that wild Penicillium developed differently between the two countries, leading to slightly different versions of the enzymes.
As moulds like Penicillium produced antibiotics to enable them to fight off microbes, it’s likely that the UK and US strains differ because they had adjusted to best fight the local bacterial populations that each strain encountered.
Paper author and biologist Ayush Pathak, also of Imperial College London said that their research could help illuminate novel solutions to fighting antibiotic resistance.
Sir Alexander Fleming’s findings have paved the way for further innovations in the world of antibiotics. Of course, someone else might have come across it, but it was he who realised that what he saw had a significance, therefore it’s only right that he takes the credit.
Others have taken the research further, that’s only natural, that’s called progress, and in the case of penicillin, thank heaven for that because it’s been proven to be so valuable and he’s literally saved hundreds of millions of lives.