The alarming rise of antibiotic resistance
Scientists warn current practices must be halted if the world is to avoid a major medicinal crisis
Scientists attending a recent meeting of the American Society for Microbiology reported they had uncovered a highly disturbing trend. They revealed that bacteria containing a gene known as mcr-1 – which confers resistance to the antibiotic colistin – had spread round the world at an alarming rate since its original discovery 18 months earlier. In one area of China it was found that 25% of hospital patients now carried the gene.
Colistin is known as the “antibiotic of last resort”. In many parts of the world doctors have turned to its use because patients were no longer responding to any other antimicrobial agent. Now resistance to its use is spreading across the globe.
In the words of England’s chief medical officer, Sally Davies: “The world is facing an antibiotic apocalypse.” Unless action is taken to halt the practices that have allowed antimicrobial resistance to spread and ways are found to develop new types of antibiotics, we could return to the days when routine operations, simple wounds or straightforward infections could pose real threats to life, she warns.
That terrifying prospect was the focus of a major international conference due to be held in Berlin this week. Organised by the Wellcome Trust, the UN and several national governments, the meeting was attended by scientists, health officers, pharmaceutical chiefs and politicians. Its task is to try to accelerate measures to halt the spread of drug resistance, which now threatens to remove many of the major weapons currently deployed by doctors in their war against disease. At present about 700,000 people a year die from drug-resistant infections. However, this global figure is growing relentlessly and could reach 10 million a year by 2050. The danger, say scientists, is one of the greatest humanity has faced in recent times. In a drug-resistant world, many aspects of modern medicine would simply become impossible. An example is provided by transplant surgery. During operations, patients’ immune systems have to be suppressed to stop them rejecting a new organ, leaving them prey to infections. So doctors use immunosuppressant cancer drugs. In future, these may no longer be effective.
Or take the example of more standard operations, such as abdominal surgery or the removal of a patient’s appendix. Without antibiotics to protect them during these procedures, people will die of peritonitis or other infections. The world will face the same risks as it did before Alexander Fleming discovered penicillin in 1928.
“Routine surgery, joint replacements, caesarean sections and chemotherapy also depend on antibiotics, and will also be at risk,” says Jonathan Pearce, head of infections
and immunity at the UK Medical Research Council. “Common infections could kill again.”
As to the causes of this growing threat, scientists point to the widespread misuse and overuse of antibiotics and other drugs and to the failure of pharmaceutical companies to investigate and develop new sources of general medicines for the future. Western doctors are overprescribing antibiotics to patients. In many countries, both land and fish farmers use antibiotics as growth promoters and indiscriminately pour them on to their livestock. In the latter case, the end result is antibiotics leaching into streams and rivers with alarming results, particularly in Asia.
“In the Ganges during pilgrimage season, there are levels of antibiotics in the river that we try to achieve
in the bloodstream of patients,” says Davies. “That is very, very disturbing.”
The creation of these anti-biotic-laden waters and banks of drug-soaked soils is ideal for the development of “superbugs”. Rare strains that are resistant to antibiotics start to thrive in farm animals and emerge as highly potent infectious agents that then spread across the planet with startling speed. Examples of these include tuberculosis, which was once easily treated but which, in its modern multi-drug-resistant form, claims the
lives of 190,000 people a year.
Another even more revealing example is provided by colistin. “Colistin was developed in the 50s,” says Matthew Avison, reader in molecular biology at Bristol University. “However, its toxic side-effects made it unpopular with doctors. So it was taken up by vets and used in animals. But as resistance – in humans – to other antibiotics has spread, doctors have returned to colistin on the grounds that it was better than nothing.”
But the antibiotic’s widespread use as a growth promoter for poultry and pigs in Asia had – by this time – encouraged the evolution of resistant strains and these have now spread to humans.
Bans on the agricultural use of antibiotics are being imposed in Asia but have come far too late to be effective, a problem acknowledged by Lord Jim O’Neill, whose report to the UK government on antimicrobial resistance was published last year. “When we were putting our report together, colistin resistance was considered to be a problem that would not affect
us for some time. Now we find it has already spread all over the place.”
The report put forward proposals to stop antibiotic resistance from overwhelming health services. In particular, it argued that drug companies should foot the bill for the development of new antibiotics and that patients should not be allowed to get them without a test to ensure they are needed.
The proposal is popular, although Professor Alastair Hay of Bristol University counsels caution. “It is a very good idea, but … a new type of diagnostic test like this will also add time and work for our already overburdened health service,” he points out.
Then there is the issue of travel, one of the biggest problems we face over the spread of antimicrobial resistance, according to Davies.
Tourism, personal hygiene, farming, medical practice – all are affected by the issue of antibiotic resistance, and it will be the task of the conference to highlight the most effective and speedy solutions to tackle the crisis.
In the Ganges during pilgrimage season, there are antibiotics levels in the river that we aim for in patients