Antimicrobials in agriculture

As a new report is published, BBSRC’s Adam Staines discusses the complex issues surrounding antibiotic use in the food chain.

Adam Staines

Despite lots of wider media coverage in the last year on antimicrobials and antimicrobial resistance many people are still asking basic questions about what resistance is, what is resistant to what, and why should I really care?

Any societal complacency over the importance of antimicrobial drugs is actually a testament to their success. Many of the diseases that ravaged us and our livestock industries for centuries until Alexander Fleming and penicillin came along have been so successfully controlled we no longer fear them, or even recognise the names. (The leading causes of human death in 1900 were bacterial infections causing pneumonia, tuberculosis, diarrhoea and enteritis.)

Since then researchers have identified many other antibiotics both from natural sources and through novel chemistries. This triumph over nature has both benefited human and veterinary medicine. Antibiotics have ensured a wide variety of animal species do not suffer from painful diseases and have developed our global livestock industry, ensuring we have affordable food and providing a key source of nutrition.

The ‘super bug’ MRSA (methicillin-resistant staphylococcus aureas). Excessive use of antibiotics in livestock is under focus.

But in the midst of our success the bacteria have been starting to fight back. It has been known since we discovered antibiotics that over time resistance can emerge, and in 2014 the UK Prime Minister commissioned Jim O’Neill, a globally respected economist, to investigate how the global economy can address the rise in resistant bacteria.

A global problem needs global action

The first report from Jim O’Neill’s team identified the cost of us doing nothing about the resistance problem: 10 million deaths a year (a higher cause of death than cancer by 2050) and a cost to the global economy of USD$100 trillion. This report identified the need among other actions for more scientific research.

Today, the next report is published with a focus on the role of antimicrobials in agriculture.

In some countries more antimicrobials are given to animals than humans, such as in the US where they are given to animals as growth promoters. As with humans, the more you use them the greater the chance of resistance developing.

Antibiotics are widely used as growth promoters in the US beef industry.

This is especially a problem in countries where antibiotics are used prophylactically (before any animals get sick) or metaphylactically (to protect the whole herd once one animal becomes sick). However, failure to treat sick animals has considerable ethical implications in addition to the effects on food supply.

Some countries in Europe have lower antibiotic usage than the UK, so one might suggest that we just to copy their practices. But we must be mindful of the differences in countries’ agricultural systems. For example, the UK has a greater number of pigs in outside pens, which is potentially better for the pigs’ wellbeing, but changes the environmental exposure to different diseases. In addition, tighter regulation in the EU does not address the global issues outside of EU control.

One size doesn’t fit all: pigs are kept outside in the UK, so their antibiotic needs are different to pigs in Denmark where they are kept indoors.

Excessive, unregulated use of antimicrobials in animals represents a risk to future food production, as well as to human health. If there were separate diseases in animals and humans with different treatments the problem would be simpler. However, in many cases the bacteria and the drugs used to treat them are the same. Worryingly, some so-called ‘drugs of last resort’ for human infections are used regularly in animals and a recent paper showed wide spread resistance emerging in animals and humans as a result.

Action stations

One key point the report notes is the role vaccines can play. Vaccine development is a key priority for Global Food Security (GFS) programme partner BBSRC and vaccines do offer a complementary approach to antimicrobials. This will require a combination of extensive research and partnership with the relevant industries.

Governments around the world are beginning to take coordinated action.

Resistance in bacteria that are pathogenic to humans and animals are of primary focus, but there are other significant issues affecting the food chain. There is a growing issue with increasing fungal resistance to crop protection treatments, and we need to research both novel treatments and alternative strategies such as breeding resistant varieties of crops.

The report also notes the wider issues of parasites and the related challenges in developing new anti-parasitics and alternative treatment strategies. All of this is going to require a global research effort and the full intellectual capital of the UK research base working in a multidisciplinary way – activities the GFS programme was set up to facilitate.

In addition to the prioritisation of AMR and an annual multi-million investment in addressing the challenge, we at BBSRC have been working together with other Research Councils and GFS partners on a number of joint calls. The UK Government also announced further investment in AMR in the recent Comprehensive Spending Review.

With world leading microbiologists in the UK and with appropriate investment in fundamental research, we can hopefully get back on top of this challenge so that we can enjoy the benefits of managed bacterial pathogens for the century to come.

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About Adam Staines

Adam is the joint-Head of Strategy for Agriculture and Food Security at BBSRC which includes responsibilities across the food-chain. In addition to working on BBSRC’s strategic delivery of agriculture and food security, and its contribution to the Global Food Security programme, Adam also has strategic responsibility for AMR within BBSRC. In addition to roles in BBSRC over the past twelve years Adam has also worked for the Government Chief Scientists office (Go-Science), and as Head of Policy for Research Councils UK Strategy Unit.

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