We Need to Talk About Antibiotic Resistance

Written by Science, Science & Tech

Usually, when people hear the phrase ‘global catastrophe’ their minds immediately jump to events of immense size, such as a nuclear meltdown, an earthquake creating a tsunami or a meteor crashing onto Earth. But an equally threatening, if slightly more likely, scenario may be caused by something so small that it cannot even be seen by the naked eye: antibiotic resistant bacteria. These are bacteria that through random mutations in their genes have developed resistance to certain antibiotics, which gives them a selective advantage over other bacteria.

The principle of antibiotic resistance can be demonstrated using Darwin’s theory of natural selection. Consider a population of 100 bacteria, all of which are susceptible to a certain antibiotic (for example penicillin). One out of the 100 bacteria undergoes a random genetic mutation that grants it the ability to survive in the presence of penicillin, i.e. it is now resistant to penicillin. If this population of bacteria is exposed to penicillin, 99 of the bacteria will die while the penicillin-resistant one will survive. Due to the lack of competition, the sole surviving bacterium now has greater access to a nutrient-rich environment where it can thrive and repeatedly divide, to give rise to a population of penicillin-resistant bacteria. In addition to passing down the gene of antibiotic resistance to their offspring, bacteria can also transfer this gene to other species of non-resistant bacteria, in a process called conjugation.

Image: NIAID, via Wikimedia Commons

Image: NIAID, via Wikimedia Commons

In 2014 the World Health Organisation issued a press release stating that unless immediate action is taken to combat antibiotic resistance, “…the world is headed for a post-antibiotic era, in which common infections and minor injuries which have been treatable for decades can once again kill… “.

But what is it that brought about this surge in antibiotic resistance?

The answer lies in the use, or rather the overuse and the misuse of antibiotics ever since they’ve been commercially available starting in the mid-1940s. One of the most significant ways in which humans have contributed to the increase in antibiotic resistance is by using antibiotics as ‘growth promoters’ in farm animals, in order to maximise profit. This overexposure of the farm animals’ bacterial populations to antibiotics leads to a rapid development of antibiotic resistance, which can then easily spread to human bacterial populations.

Drug-resistant infections kill 700,000 people every year

Unfortunately, things don’t get any better as far as antibiotic use in humans is concerned. Ever since its accidental discovery by Sir Alexander Fleming in 1928, penicillin and antibiotics in general have been overprescribed by doctors to treat misdiagnosed diseases on which they have no effect whatsoever, such as infections caused by viruses. Again, the bacterial populations within the human body that will be exposed to the antibiotic will almost certainly develop some degree of resistance to it, as a result of this unnecessary exposure.

Sir Alexander Fleming discovered world's first antibiotic by accident - after finding mould growing in a culture dish. Image: Ministry of Information Photo Division Photographe, via Wikimedia Commons

Sir Alexander Fleming was researching influenza when he found mould growing in a culture dish – which led to discovery of world’s first antibiotic. Image: Ministry of Information Photo Division, via Wikimedia Commons

As if that were not enough, even when the use of antibiotics is actually warranted, many people stop taking them a few days after they’ve been prescribed because they start feeling better. What these people don’t realise though is that by doing so, instead of killing the bacteria causing their disease, they only weaken them and thus allow them to survive and reproduce, eventually forming populations that will very likely be resistant to the antibiotic initially used to kill them.

It is estimated that deaths from drug-resistant infections could rise to 10 million by 2050

An obvious solution to the problem would be to keep coming up with new antibiotics. Sadly, this is easier said than done, since it’s becoming increasingly difficult for pharmaceutical companies to develop new antibiotics, which in turn has led to them investing their funds in more profitable drug developments.

Years after the discovery of penicillin, Fleming said: “the thoughtless person playing with penicillin is morally responsible for the death of the man who finally succumbs to infection with the penicillin-resistant organism”. Maybe it’s time we started putting some serious thought into how we use our antibiotics.

Last modified: 11th October 2018

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