The Liverpool View: Antibiotic stewardship and animals

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species-appropriate husbandry

antibioticsCow-1wDr Nicola Williams is a Lecturer in Zoonotic Disease in the University of Liverpool's School of Veterinary Science, and part of the Heseltine Institute for Public Policy and Practice

"Antibiotic resistance, an inevitable consequence of evolution, is one of the major issues facing human medicine. This has led to warnings that we could return to the situation of a century ago when infectious diseases that we have become used to considering as relatively minor, routinely resulted in death.

Furthermore, there have been no new classes of antibiotic discovered for nearly thirty years, so assuming that a new wonder drug will come along and bail us out is no more than wishful thinking. Thus the emphasis has to be on stewardship; the careful use of existing antibiotics to reduce the selection for - and maybe even the amount of - resistance.

Antibiotic use in (non-human) animals

While few would argue against the largest driver of resistance in human medicine being antibiotic use (and abuse) in people, there remains the issue of how much influence antibiotic use in (non-human) animals has on selecting for resistant bacteria in people. The use of antibiotics in the past, and still in many parts of the world including the USA, as 'growth promoters' in healthy farm animals has often been cited as posing a clear risk to human health, although the direct evidence for this risk having been realised is by no means conclusive. And although resistance is increasing in animals, unlike in people it is not a common clinical problem in terms of treating domestic animals.

Interestingly, while there is evidence for veterinary to human transmission of antibiotic resistance, detailed molecular studies increasingly show that the genes responsible for resistance in human and non-human animal pathogens are often not the same - in other words they have evolved separately. Our own studies in wildlife suggest that transmission of resistance and resistance genes between species sharing the same environment is uncommon.

[callout title= ]"Until recently, the debate around antibiotic resistance in people and antibiotic use in animals has consisted largely of vets and medics regarding each other as the main problem and denying their own culpability"[/callout]That’s not to say that cross species transmission doesn’t occur, of course. Our research at Liverpool and elsewhere has also shown that the MRSA seen in cats and dogs probably comes originally from people, and that cats and dogs can then transmit it back to people.

Until recently, the debate around antibiotic resistance in people and antibiotic use in animals has consisted largely of vets and medics regarding each other as the main problem and denying their own culpability. Only over the last few years has this become a more grown up debate, with both sides taking a ‘One Health’ approach, recognising their own responsibilities and the necessity of both working together and putting their own houses in order.

It was against this background that the University hosted a symposium, Promoting Good Veterinary Antimicrobial Stewardship, on European Antibiotic Awareness Day. The event, sponsored by the Veterinary Medicine Directorate (VMD), and co-chaired by Professor Susan Dawson, Head of the School of Veterinary Science, and Professor Peter Borriello, Chief Executive of the VMD, was attended by leaders in the veterinary profession with speakers drawn from both human and veterinary medicine. Much of the debate was around culture and behaviour change - what one speaker described as the 'etiquette of prescribing'.

Various veterinary professional organisations, dealing with pets, horses and food animals, presented guidance (as opposed to guidelines) and online tools developed to help veterinary practices engage and take ownership of antibiotic stewardship through developing their own local guidelines. The overall approach is to make it easier for vets to prescribe responsibly and sustainably, with a move towards holding antibiotics essential for human medicine in reserve.  This emphasis on bottom up engagement can be highly effective, with 90% plus reductions in the use of important antibiotics seen in some practices adopting such approaches. Indeed, local policies empower and engage in a way that top-down, one-size-fits-all policies often don't.

[callout title= ]"This emphasis on bottom up engagement can be highly effective, with 90% plus reductions in the use of important antibiotics seen in some practices adopting such approaches. Indeed, local policies empower and engage in a way that top-down, one-size-fits-all policies often don't"[/callout]Of course, top down pressure can reinforce local behaviours. Having policies and guidelines on responsible antibiotic use are now requirements of veterinary practice accreditation, and responsible use a requirement of the veterinary surgeon's Code of Professional Conduct - in other words vets can be disciplined or struck off for using antimicrobials irresponsibly.

Following the medical example, apps and i-formularies are being developed for veterinary use, while the Equine Veterinary Journal is the first in the world to require evidence of good antimicrobial stewardship prior to publication of clinical research studies. Not that everything is easy. Sometimes the only antibiotic licensed for a particular species or condition is not the antibiotic that common sense would suggest should be used, and marketing and economics are also important drivers in antibiotic choice. And, as one speaker described it, the veterinary profession is no different than any other: there are the good majority, a bad very small minority, but also an ugly minority who are often difficult to engage, especially in an industry comprising small private businesses without the structures of, say, the NHS.

But in both human and veterinary medicine the big pressure comes from patients and clients. Studies on prescribing among medical GPs suggest that however engaged and bought-in your doctor might be, he or she may well cave in and prescribe antibiotics if harangued enough during a busy surgery, and in highly competitive farm animal practice, farmers will simply move around until they find a practice that treats as they expect rather than what is strictly necessary.

Importance of education

This highlights the importance of education of patients in human medicine and of animal owners in veterinary medicine, be they dog owners or farmers . We all need to understand how important it is to protect antibiotics if we want to be able to keep using them in the future.

Thus, as in so many areas of life, while more scientific evidence is needed, it's really human behaviour that's most important. And people are complex, both as individuals and in groups.  Work in human medicine suggests that engaged prescribers may behave better than those simply following top-down guidelines - which is perhaps good news for those trying to organise the disparate and independent-minded veterinary profession.

The latest approach to encouraging good prescribing practice in human medicine goes beyond apps and into 'gamification' - online phone-based games that test clinical decision making, construct league tables and invite patient involvement. However serious the issue, this is starting to sound like fun."

[callout title=More]In Brief: Vets mark European Antibiotic Awareness Day[/callout]

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