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Resistance to resistance is not futile

02 Dec 2015

If antimicrobial resistance is to be tackled, we need to not only change medical practice and educate the public, but also address the widespread overuse of antibiotics in agriculture, warns Dr Muiris Houston.


We’ve come a long way since Alexander Fleming discovered penicillin in 1928. Antimicrobials are a cornerstone of modern medicine.

We take them very much for granted — overly so on a daily basis, and perhaps more appreciatively when we rely on them during organ transplantation or to enable us to receive heavy doses of chemotherapy.

However, inappropriate use can cause microorganisms to become resistant to antimicrobial treatments, risking treatment failure and increased mortality.

Anti-microbial resistance (AMR) is one the greatest threats to global health and there is a growing scientific and political consensus that urgent action is needed.

A recent discovery by Chinese scientists of a gene that renders Gram-negative bacteria resistant to the last line of currently available antibiotics is just the latest indication of this growing global threat. The highly resistant strain of E. coli is no longer sensitive to colistin, a polymixin antibiotic.

Pig farms
Scientists found the bug was able to transfer its immunity to the drug to other strains via the mobile gene mcr-1. They were able to track it from pig farms to patients infected with E. coli and Klebsiella in hospitals in the Chinese provinces of Guangdong and Zhejian.

Lead researcher Prof Jian-Hua Liu from the South China Agricultural University in Guangzhou said: “Our results reveal the emergence of the first polymyxin resistance gene that is readily passed between common bacteria such as Escherichia coli and Klesbsiella pneumoniae, suggesting that the progression from extensive drug resistance to pan-drug resistance is inevitable.”

Increasingly heavy use of colistin by Chinese farmers helped E. coli to acquire the gene, which is then passed on to humans via meat consumption. The discovery that resistance can be transferred between bacteria and across bacterial species is a truly alarming development.

Resistance to antibiotics continues to increase in Europe, with rates in some organisms reaching 25 per cent or higher in several EU member states.

Each year, infections by multidrug-resistant bacteria cause at least 25,000 deaths, costing healthcare systems and governments more than €1.5 billion.

In Europe, 35 per cent of hospitalised patients are given at least one antimicrobial agent with many receiving two or more, either for the treatment of an infection or as surgical prophylaxis.

Yet one-third of antibiotic use in hospitals fails to comply with evidence-based guidelines.

The discovery that resistance can be transferred between bacteria and across bacterial species is a truly alarming development. Pic: Getty Images

Stewardship programme
Here in Ireland, HIQA has initiated a national antibiotic stewardship programme aimed at tackling some of the issues behind drug resistance.

The aim of antimicrobial stewardship is to ensure that every patient receives the right antimicrobial therapy, at the right dose, route and duration, for the right infection type at the right time.

But as well as changing medical practice we need to look at educating the public.

A recent WHO survey of 10,000 people in 12 countries discovered some dismaying and even dangerous misunderstandings about antibiotic resistance. A third of survey respondents thought they should stop taking an antibiotic prescription when they start to feel better, thus facilitating resistance.

When it came to overuse of antibiotics some additional troubling misunderstandings emerged: nearly two-thirds of respondents thought antibiotics were effective treatments for colds and the flu.

And one-quarter of respondents felt it was okay to take antibiotics that had been prescribed for someone else, as long as they were being used to treat the same illness.

Less unexpectedly, three-quarters of those surveyed misunderstood how resistance works, thinking it was their bodies that became resistant to antibiotics rather than the bacteria.

The most hopeful survey result was that 73 per cent of respondents said farmers should reduce the amounts of antibiotics used in food production; the drugs are mostly used to promote growth of livestock, and not to treat sick animals.

With agricultural use of antibiotics so widespread and exceeding human use many times over, I believe the efforts of HIQA, the WHO and others will be for nought if we don’t put a complete stop to this inappropriate use of a precious resource.


Click here to view the full article which appeared in Irish Medical Times: Opinion