In 2019, more than a million people died globally due to common bacterial infections that were previously treatable with antibiotics.
Antimicrobial resistance occurs when bacteria, viruses, fungi and parasites mutate so that they no longer respond to medication. It has become a leading cause of death worldwide, killing more people than AIDS or malaria.
‘Antimicrobial resistance is everywhere,’ said Dr Hein Imberechts, from the Sciensano research institute in Brussels, Belgium and scientific coordinator of the One Health European Joint Programme (EJP). ‘The real threat is not the resistance itself, it’s the misuse of antimicrobial drugs,’ he said.
The over-prescription of antimicrobial medications such as antibiotics and antifungals is largely responsible for the evolution of superbugs. These are types of pathogens that can survive and reproduce while drug-sensitive strains are wiped out.
It is a problem for animal health as well. Drug-resistant bacteria can infect livestock and poultry on farms, for example, and if animals can’t be treated, it can affect their growth, productivity or even lead to death.
‘Resistant bacteria are an increasing problem in veterinary medicine,’ said Dr Hans Spoolder, a senior animal welfare scientist at Wageningen University in the Netherlands and coordinator of the HealthyLivestock project.
Antimicrobial resistance is everywhere. The real threat is not the resistance itself, it’s the misuse of antimicrobial drugs.
In some countries, farmers may give livestock low doses of antimicrobials to make them grow faster, for example, or antibiotics may be administered to an entire herd as a preventative measure.
Working with 44 food, veterinary and medical institutes across Europe, the One Health EJP programme is trying a new approach to disease surveillance and prevention. It aims to get the human, animal and environmental health sectors, which are normally separate domains, to join forces.
‘We are convinced that we have to look at animal diseases, human diseases and the environment as being one ecosystem,’ said Dr Imberechts. ‘There may be spillover (between these sectors) and that is very probably what happened with the coronavirus SARS-CoV2,’ he said, referring to the possible zoonotic effect, where diseases found in animals cross over into humans.
A project called ARDIG, which is part of One Health EJP, has been examining the dynamics of antimicrobial resistance in animals, humans, food and the environment in the UK, Norway, France, Germany, Spain and the Netherlands.
How microbials are used and recorded varies between countries and so do levels of disease-resistant bacteria. Some countries track the amount of antibiotics sold over a specific period rather than how much has been prescribed to animals. Drugs are sometimes administered en masse to large numbers of animals rather than to unwell individuals.
We are convinced that we have to look at animal diseases, human diseases and the environment as being one ecosystem.
‘Standards are needed to harmonise different approaches,’ said Dr Imberechts. ‘There are a number of errors in the registration of the use of antibiotics in animals, whereas it’s far easier for humans.’
To help standardise the data on pathogens and drug resistance, the ORION project has created a glossary of over 1000 relevant terms. People working in different regions and sectors can better understand each other by using the same terminology.
The Cohesive project has developed an open-source online platform that will facilitate information sharing about potential outbreaks of foodborne diseases that could be transmitted between species, for example from animals to humans. ‘This is very important if you want to compare (information) with other countries and set alerts,’ said Dr Imberechts.
Pathogens are less likely to become untreatable if antimicrobial treatments are used responsibly. As part of the HealthyLivestock project, Dr Spoolder and his colleagues are employing four early-intervention and preventive strategies to reduce the need to use antimicrobials in pigs and chickens.
The project focuses on Europe and China, two regions where active research into antimicrobial resistance is already underway.
The first strategy is to use preventive measures to stop pathogens from entering farms in the first place. One approach is to develop an app that can be used to assess risk factors for the deadly African swine fever virus on pig farms in China.
HealthyLivestock is also researching ways to prevent diseases from spreading by early detection of health problems in poultry flocks using a camera system. By comparing behavioural patterns in diseased and healthy chickens, they are trying to identify those that may be unwell based on their movements.
‘We are still developing the technology but it’s very promising,’ said Dr Spoolder. ‘There is still a lot to gain with respect to disease detection.’
Greater use of targeting will also reduce the amount of microbials used and could therefore lower the risk of developing resistance. ‘If you know which animals are ill, then you (should) medicate them and not all the animals, including the healthy ones in your group,’ said Dr Spoolder.
Improving resilience in animals makes them less likely to become ill. Research focusing on female pigs has revealed that the conditions in which they are kept affects the health of their offspring.
There is a very direct effect from stress in the mother to the resilience of their offspring.
Sows that live in groups and move around freely give birth to piglets that have stronger immune systems and can better withstand pathogens compared to those that spend their lives in stalls.
Sow stalls have been prohibited in the EU since 2013, except for a few weeks during pregnancy, but they are still allowed in China. ‘There is a very direct effect from stress in the mother to the resilience of their offspring,’ said Dr Spoolder.
Other experiments indicate that more space and straw are environmental factors that allow pigs to recover more quickly from infections.
With an ambitious target to reduce sales of antimicrobials for farmed animals and aquaculture in the EU by 50% by 2030, animal health and welfare plans will start to play a greater role in reducing disease.
The HealthyLivestock project will be organising an industry day for practitioners and scientists to meet and discuss innovations to fight antimicrobial resistance in livestock farming on 23 June 2022 in Bologna, Italy.