The history of antibiotics

The discovery of penicillin

The discovery of penicillin by Alexander Fleming in 1928 is a landmark scientific discovery. But how does this rank against other scientific discoveries?

In 2010, a survey of more than 400 UK academics highlighted the discovery of the structure of DNA, by James Watson and Francis Crick, as the most important breakthrough made by researchers at UK universities. This discovery came above, for example, genetic fingerprinting, the first working computer and the contraceptive pill.

Scientific greats are positive role models

It has been argued that scientific greats, like Fleming, can be positive role models for aspiring scientists, helping them understand different ways to succeed with examples for overcoming obstacles.

Others argue that when someone is held up as a role model, nuances can be lost, from failed experiments to important collaborations with other researchers. This can give an incomplete, often unrealistic and sometimes intimidating picture, of what scientific research is like.

What scientist has inspired you most?

Perhaps you will pick Newton, Pasteur, Curie or Einstein? At York, we have a special affection for Professor Dorothy Hodgkin, who was awarded the Nobel Prize for Chemistry in 1964.

Professor Hodgkin visited the University of York frequently between 1976 and 1988, to write up the findings of a total of more than 30 years’ research into insulin structures. One of our research buildings, built-in 2012, bears her name.

Those of you considering picking a cult TV scientist may like to know that, in 2004, the ‘Muppet Labs’ Dr Bunsen and his assistant Beaker topped a poll (based on more than 40,000 votes) for the UK’s favourite cult TV boffin!

Notable scientific discoveries

Interestingly, the discovery of penicillin by Fleming was accidental. Before going on holiday he left some unsterilised agar plates near an open window – luckily a common mould landed on the plates and just before washing them, Fleming noted a clear ring in the jelly around some of the spots of mould, showing inhibited bacterial growth.

A significant number of other notable scientific discoveries have been made by chance or serendipitously, and we will return to this topic in week 4. In the meantime, here are some other biologically active compounds discovered by accident.

Biologically active compounds discovered by accident

• Denatonium benzoate (Bitrex, C₂₈H₃₄N₂O₃) – during a research programme aimed at developing a new local anaesthetic, similar to lidocaine, scientists accidentally discovered the most bitter substance known. It is in the Guinness World Records. Despite having very similar structures, lidocaine and denatonium benzoate have vastly different biological effects. Bitrex is added to numerous household products, from antifreeze to liquid laundry detergents, to prevent accidental posioning. Even cards for the Nintendo Switch gaming console are coated in Bitrex, to deter children from ingesting them (due to their small size).

• Rogaine (Minoxidil, C₉H₁₅N₅O) – first marketed as Loniten, a medicine used to treat high blood pressure, but users observed it darkened their hair and caused hair growth; a more dilute formulation is now sold as a direct application to the scalp, to treat hair loss.

• Somnote (Chloral hydrate, C₂H₃Cl₃O₂) – in the body, chloral hydrate (Cl₃C–CH(OH)₂) was expected to form chloroform (CHCl₃), which could induce sleep; no chloroform is formed, but chloral hydrate was found to be a sedative becoming the world’s first mass produced synthetic hypnotic (fans of old movies will know it as a “Mickey Finn”).

The discovery of the antibiotic azithromycin (C₃₈H₇₂N₂O₁₂) is interesting. After 8 years of hard work to find an improved version of the antibiotic erythromycin (C₃₇H₆₇NO₁₃) (which stops bacterial cells from growing and multiplying by interfering with their ability to make proteins), the chemical company Pfizer was preparing to end its research into compounds with large rings (called macrolides).

However, as can happen in medicinal research and development, the week before the program was to be formally ended, the team hit upon a novel compound, which was called azithromycin – this is not only a potent antibiotic effective against a variety of bacteria, but, fortuitously it is delivered directly to the site of infection!