Bacteria are becoming more and more resistant to antibiotics – and this could have extremely serious implications for global public health. Simon Wilson reports.
What’s happened?
A shocking warning came from Britain’s chief medical officer – the resistance of bacteria to antibiotics is now so widespread that it presents a “catastrophic threat” to Britain that ranks alongside terrorism or climate change.
Professor Dame Sally Davies warned that if we don’t act – by using existing antibiotics more effectively and developing new ones – then within 20 years, “we may be back in an almost 19th-century environment where infections kills us as a result of routine operations”.
Davies’ warning echoes that of the director-general of the World Health Organisation, who last year said the world is facing the “end of modern medicine as we know it. Things as common as strep throat or a child’s scratched knee could once again kill.”
Why are antibiotics so important?
Because they treat infectious diseases that were once routine killers and make much of modern surgical medicine possible. By killing bacteria or inhibiting their growth, antibiotics let medics perform operations that would otherwise kill.
Similarly, treatments for cancer, including chemotherapy and radiotherapy, which can damage the immune system, require antibiotics to give the body’s defences a better chance of coping. And organ transplants, too, need antibiotics.
Recipients typically require a lifetime of drugs that suppress the immune system to stop it attacking the transplanted organ; antibiotics are then needed to do the immune system’s job. Without them, the medical advances of the past 80 years could be wiped away at a stroke.
Is resistance a new problem?
No, but it’s become far worse in recent decades with the increased use of antibiotic drugs. The use of antibiotics inevitably creates a survival ‘incentive’ for bacteria to evolve resistance. These new strains can then thrive and outcompete the old bacteria, which are killed off by the old drugs.
In addition, bacteria are hosts to loops of DNA known as plasmids, that can spread the resistance genes around from one bacteria to another.
Antibiotic resistant genes have mushroomed in recent decades as the use of antibiotics became widespread worldwide. Among the most notorious of the products of these genes is an enzyme known as New Delhi metallo-beta-lactamase 1 (NDM-1), which originated in India.
It can confer resistance to antibiotics that are widely used in Britain (such as penicillin) and can transform a host bacterium (eg, Escherichia coli) from a nuisance into a killer superbug.
Have antibiotics been misused?
Yes. They have been overprescribed and hence overused. Every time we use antibiotics, we give bacteria a chance to evolve immunity. In many parts of the world, antibiotics are available over the counter.
Even in places like Britain where they aren’t, doctors have prescribed them for viral infections, such as cold symptoms or flu, against which antibiotics have no effect.
According to one study, by US professor James Hughes, about 50% of antibiotic use is unnecessary or inappropriate. Similarly, every time we don’t finish a course of antibiotics because we’ve started to feel better, we are helping bacteria hone their defence mechanisms.
As Alexander Fleming himself explained when accepting the Nobel prize in 1945, “the ignorant man may easily underdose himself and by exposing his microbes to non-lethal quantities of the drug make them resistant”.
What can be done?
The main issue is what the chief medical officer called the “discovery void” scandal – an absence of innovative new antibiotic drugs since the 1980s. Early researchers appear simply to have got lucky.
As with aspirin (the drug that founded the modern pharmaceutical industry and has never been bettered for many applications), penicillin and its contemporaries have proved hard to improve upon.
When big pharma has poured money into the problem in recent years, it’s come up empty-handed. Both GlaxoSmithKline and Novartis invested (and lost) millions in applying genomics (how genes behave) and proteomics (how proteins behave) to the issue of antimicrobial resistance.
Indeed, antibiotics are looking bad for business. They cost hundreds of millions in research and development; clinical trials are more challenging and costly than for many other drugs; and they are generally only taken by patients for a week or two.
Compared with drugs aimed at controlling conditions, such as statins for high cholesterol, or pills to control heart conditions or diabetes, the potential profits are therefore small. It’s this “market failure” that needs an urgent solution from policymakers and businesses.
The tragedy of the commons
The problem of rising antimicrobial resistance is one that economists refer to as the “tragedy of the commons”. The tragedy is that individuals have an incentive to overexploit commonly owned resources, to their own benefit, but to the ultimate detriment of the whole community.
The common resource of antibiotics, in other words, needs to be protected from overuse for the good of us all. That means regulation, partly via stricter dispensing guidelines, and partly via state backing for new research – perhaps in the form of financial incentives, prize funds, guaranteed-purchase arrangements for new drugs, patent extensions, tax credits and so on.