Antimicrobial resistance (AMR) is a global public health risk. It stops treatments (such as antibiotics, antivirals, antifungals and antiparasitics) from working and therefore reduces our ability to combat infections. Although AMR occurs naturally, the overuse and misuse of antimicrobial drugs (for example, the use of the antibiotic, colistin, as a growth promoter in meat production) has accelerated AMR to the point where clinical cases of infection with resistant microorganisms have drastically risen.
It has been referred to as ‘the silent pandemic [that] could have consequences far more deadly than COVID.’ In 2014, economist, Jim O’Neill predicted that by 2050, deaths caused by AMR will reach 10 million, exceeding those caused by cancer and diabetes. Sobering data from 2019 found there were an estimated 4·95 million (3·62–6·57) deaths associated with bacterial AMR, demonstrating that we are already halfway to the 10 million mark.
What are governments doing about AMR?
The UK government has published its 20-year Vision for Antimicrobial Resistance to control and mitigate AMR by 2040. The delivery of this will be achieved through a series of 5-year National Action Plans (NAP). The Scottish Government feeds into the UK NAP. All action plans have an integrated ‘One Health’ approach to addressing the AMR
Research by scientists at The Hutton
Researchers at the Hutton are looking at how AMR might be transferred from the environment to the food chain. The aim is to see whether certain farm management practices or behaviours might influence the levels of AMR on the farms. The study focusses specifically on ruminant (dairy), arable and agroforestry farming under organic, conventional or integrated practices. The farms are in the north-east, east and central Scotland, and includes the experimental platforms at Glensaugh and Balruddery. Over a hundred samples were collected representing potential sources (e.g. manure), pathways (e.g. water, soil) and receptors (e.g. crops, livestock) of AMR. They were analysed for levels of different AMR genes, which causes microbes to become resistant. The genes belong to the major classes of antibiotics, such as beta-lactams (which includes penicillin) and tetracyclines.
AMR in Agri-food
As AMR is naturally present in the environment, there is potential for it to be transferred to food. This can be exacerbated by certain practices, including the spreading of waste such as manure, slurry and sewage sludge with the primary purpose of adding nutrients to soil. Ready-to-eat crops such as salads are the most risky to consumers because they are eaten raw, so any AMR carrying bacteria present on the salad will not be killed off by cooking. Pathogens (germs) that are resistant to antimicrobials (the so called ‘superbugs’) are the most concerning to consumers because they cause disease, however, resistant commensal bacteria (bacteria that live in or on organisms, but do not cause harm) are also a problem because they contribute to the reservoir of AMR genes that could be transferred to the pathogens.
Understanding antimicrobial use on farms
One of the major concerns in agri-food is the use of antimicrobials in livestock animals (such as cows, pigs and chickens) because overuse can lead to more resistant bacteria. As such, there have been significant reductions in antimicrobial use, but in some sectors, the reductions in antimicrobial use have plateaued. Therefore, Hutton researchers looked at farmer’s perceptions of the link between AMR and antimicrobial use and how these perceptions may influence their behaviours. Researchers carried out a social science participant observation study on six dairy farms in Scotland under organic or conventional farming practices. They visited the farms and spent time with the farm workers as they carried out their tasks, and/or had a guided tour of the farm and asked questions about their practices and attitudes related to antimicrobial use, AMR and waste disposal on the farm. This showed that farmers had an awareness of AMR as a public health issue, and reduced antimicrobial use, which is in line with trends in the dairy industry. They were also concerned about the development of AMR in their animals, which gave them further reason to reduce antimicrobial use. They had generally not considered the risk of AMR affecting themselves, their family or farm workers, nor had they considered the risks of spreading resistant bacteria into the environment through slurry or increasing development of resistance through dumping of waste milk, which can be contaminated with antibiotics.
Identifying AMR interventions
To mitigate against increases of AMR in the farming environment, interventions must be identified and implemented. To take a more targeted approach, the quantitative and qualitative data collected by Hutton researchers will be used in a risk assessment model. This will inform where management interventions will be most effective in the food chain system to reduce foodborne risks. The risk assessment model follows a source-pathway-receptor principle (as reflected in the farm sampling) and is being developed using an approach that offers unique advantages for addressing the complexities and challenges associated with AMR risk assessment. Another advantage is that it enables collaborative model co-construction with experts and stakeholders, fostering transparency, credibility, and shared understanding of complex AMR dynamics.
Engagement across sectors
Researchers at the Hutton are collaborating widely through the newly established AntiMicrobial resistance in Agri-food Systems Transdisciplinary network, one of eight AMR networks to receive cross council funding. The network brings together industry, trade associations, policy makers, and academia involved in food production to create a future where AMR no longer threatens our food systems, where farmers can maintain healthy farming practices without overreliance on antibiotics, and where sustainable food production supports both human and animal health.
Hutton researchers have taken a multi-disciplinary approach to understanding AMR in the environment. Further research across water environments will be described in a future blog and is equally crucial in providing evidence to support risk assessment of AMR exposure.
Written by Dr Eulyn Pagaling, Dr Lisa Avery, Dr Hannah Budge, Carol Kyle, & Dr Mads Troldborg
(Main image: Dr Amy Cooper taking a soil sample. Photo credit: Lucinda Robinson)