Farming
Farming is the subject of heated discussions when it comes to antibiotic resistance. This is because antibiotics are used on a large scale in farming, and as a consequence farming is the source of new resistance in bacteria. However, there is not a huge amount of evidence that this will result in a major threat to humanity. Who are the experts to ask, where can you find information, and which studies are important? Here is our overview.
On this page: Frequently asked questions for farmers | Experts | Important studies
Frequently asked questions: for farmers
Which are the most important germs?
Probably the most well known germ is MRSA, or methicillin-resistant Staphylococcus aureus, a superbug which is resistant to treatment with multiple antibiotics. Though Europe-wide death rates are difficult to collate, MRSA outbreaks in several countries have led to increased public awareness of the threat of MRSA.
MRSA infections that come from livestock, or livestock associated MRSA (LA-MRSA) were first found in humans in 2003. Though these types of infection only account for a very small proportion of MRSA cases, a 2011 study found LA-MRSA in humans in 11 European countries, including Germany, the Netherlands, Spain and Denmark. Deaths from LA-MRSA are extremely rare, but public awareness of the infection has remained high.
This was in part because in 2015 LA-MRSA was found in meat sold in British supermarkets for the first time, showing that humans did not need to come into direct contact with livestock carrying MRSA but could also be infected through the food chain.
Resistant infections that are transferred to humans via the food chain are just one part of the problem though. There are four main problems associated with antibiotics and antibiotic resistance in agriculture.
The first is that creating resistant germs in livestock is dangerous for humans – LA-MRSA is an example of this.
The second is the creation of resistance genes that can transfer between germs. One example of this is germs that are resistant to an antibiotic called colistin. Colistin causes strong side effects in humans so it’s only used as a last resort, and because it’s used so infrequently, resistance has hardly developed in humans.
But colistin has been used widely in farming. This wasn’t thought of as a problem, until scientists discovered that resistance had developed. At first, because the resistance gene was found on a non-mobile part of the bacterial DNA, it was thought that the resistance could not be transferred from one bacteria to another. But Chinese scientists became suspicious after observing the spread of resistant germs in pig farms. Could resistance be transferred from germ to germ after all? Yes. The scientists collected samples and discovered a resistance gene located on a mobile part of the DNA. They called it mcr-1.
Since then the resistant gene has been found in other countries, as well as in humans. The discovery has spurred debate over whether the use of colistin in farming should be reduced.
The third problem is what happens to the antibiotic residues after the animals have been treated with them. Several studies have found high concentrations of antibiotic residues in the soil and water near to intensive farms.
For example, one study that looked at farming in China found high concentrations of veterinary antibiotics in a rural water system near livestock production. There were also a high concentration of resistant E. Coli germs. Although the link between the resistant germs and the high levels of veterinary antibiotics was not conclusively established, the scientists concluded that rural water systems like the one they studied are likely to have increasing concentrations of both vet antibiotics and resistant germs, unless greater care is taken over the release into the environment of antibiotic residues from livestock farming.
Disposing of these antibiotic residues into the environment could also help to create resistant germs that are dangerous for humans, and create resistant genes that can jump between germs.
The final problem of widespread use of antibiotics in agriculture is what it could show about the underlying farming methods. High antibiotic use on a farm can be a way of compensating for poor hygiene. If hygiene is poor, more animals will get sick, and more antibiotics will be used. Although high antibiotic use of itself is not always an indicator of poor animal welfare, campaigners suggest that routine use of antibiotics could be prevented by using less intensive farming methods. Intensive farming methods – where many animals are crowded together – can create more infections.
There are also a growing number of infections that are becoming harder for doctors to treat in human patients – including pneumonia, tuberculosis and gonorrhoea – because the antibiotics usually used are becoming less effective, as the germs become more resistant to them.
Other resistant bacteria which threaten human health include: campylobacter, the most common cause of gastroenteritis in humans globally which is found in most animals and frequently in poultry meat; salmonella, another foodborne disease and one in which resistant strains are beginning to develop.
Campylobacter is a foodborne infection which is generally mild, but in already vulnerable groups – the very young, very old, and those with compromised immune systems – it can be fatal. The main source of the infection is from eating contaminated meat, especially poultry.
The latest ECDC data shows that there were 214,779 confirmed cases of campylobacter infections in humans in 2013 in Europe, with over 10,000 of the people infected being ill enough to be hospitalised. 56 people died.
Several antibiotics can be used to treat campylobacter infections. Last year, data for cases in the UK suggested that resistance to one of those antibiotics – ciprofloxacin – had reached it’s highest levels in 10 years.
According to the data from Public Health England, almost one in two of all human campylobacter cases tested in England for resistance to ciprofloxacin were indeed resistant. This resistance followed an increasing trend: in 2005, 30 per cent of campylobacter isolates tested were resistant to ciprofloxacin; in 2015 it was 48 per cent.
Salmonella, like campylobacter, is a common gastroenteritis infection that is usually mild. However, depending on the type of salmonella and the susceptibility of the person infected it can be fatal.
The latest ECDC data shows that there were 82,694 confirmed cases of salmonella infections in humans in 2013 in Europe, with nearly 8,000 of the people infected being ill enough to be hospitalised. 59 people died.
Antibiotic consumption in agriculture. Learn more
Why should farmers care about this issue?
In the United States, consumer campaign groups are pressuring big food companies to remove antibiotics from their food chains and use antibiotic-free meat. McDonald’s, Subway and Chipotle are among the companies who have either eliminated antibiotics from their meat or pledged to do so.
Europe is ahead of the USA when it comes to antibiotic use – using antibiotics as growth promoters in animal feed was banned in 2006 in the EU, but is still permitted in the US. Yet UK investors have also begun to call for reduced antibiotic use in agriculture. They are particularly concerned about the use of antibiotics which are critically important to human health in animals.
Last year, investors who control more than $1trillion in assets wrote to leading global food companies, saying that they believed that while sick animals should always receive the treatment they need, the routine use of antibiotics on farms has to stop.
With the public mood shifting, it will pay in the long run for farmers to be ahead of the curve. Countries like the Netherlands and Sweden have massively reduced antibiotic use in farming without reducing their production.
In 2017, European Food Safety Authority and the European Medicines Agency urged farmers to ‘reduce, replace and rethink’ the use of antimicrobials in animals.
The use of antibiotics in animals must be kept to the minimum necessary to treat sick livestock, the agencies said, adding that antibiotics critically important to human medicine should only be used in animals as a last resort. By reducing the amount of antibiotics given to food-producing animals, farmers can help to reduce the number of resistant germs the animals carry, and help to fight against the big public health threat of antibiotic resistance.
What are the EU rules around livestock consumption of antibiotics?
In 2006 the European Commission banned antibiotics being used as growth promoters in animal feed.
In 2008 the European Council called on EU countries to develop better surveillance systems and improve data quality on both antimicrobial resistance and on consumption of antimicrobials by humans and livestock.
There is also legislation to control Salmonella at all relevant stages of production, processing and distribution in order to reduce the exposure of humans to potentially resistant Salmonella.
Routine use of antibiotics for livestock is still common in many EU countries. However, some have banned the use of antibiotic for anything other than veterinary prescribed treatment. In the Netherlands, antibiotics which are critically important to human health can only be given to sick livestock by a vet under strict conditions.
How can farmers help prevent the spread of resistant germs?
According to the World Health Organisation, the most important things farmers can do to combat the spread of resistant bacteria are:
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Only give animals antibiotics under veterinary supervision
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Stop using antibiotics for growth promotion – already banned in the EU
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Stop the routine, preventative use of antibiotics – this is banned in some EU countries but common in others
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Vaccinate animals to reduce the need for antibiotics
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Use alternatives to antibiotics where available
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Promote and apply good practice at all steps of production and processing of foods from animal and plant sources
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Improve biosecurity on farms
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Prevent infections through improved hygiene and animal welfare
Where can I find more information?
The following EU organisations have website with information on antimicrobial resistance and farming:
The European Commission is an executive arm of the European Union. When it comes to antibiotic resistance, the Commission has played a key role in raising awareness of the issue. As part of the Commission’s ‘One Health’ approach to antibiotic resistance, the European Antibiotic Awareness Day was started by the ECDC.
The Commission also promotes better surveillance of antibiotic use and resistance across EU member states, as well as supporting member states in reducing their use of antibiotics.
The European Centre for Disease Prevention and Control
The ECDC gathers data on antibiotic resistance as part of its mission to collect disease data across the EU. It is an EU agency aimed at strengthening the EU’s defences against infectious diseases, including those that have become resistant to treatment with antibiotics.
The ECDC published the Joint Interagency Antimicrobial Consumption and Resistance Analysis, which focuses on the connection between the consumption of antibiotics and resistance among humans and animals.
With the European Commission, the ECDC played a role in raising awareness through initiating the European Antibiotic Awareness day, which is held each year on November 18th.
The European Medicines Agency.
Another EU agency, the EMA protects animal and public health across EU member states. It does this by evaluating and monitoring medicines made for the EU and making sure they’re safe.
The increasing resistance of several infections to treatment with antibiotics is a high priority for the EMA, who are trying to combat the increasing global public health threat of antibiotic resistance.
Experts
Austria
Antonia Griesbacher, Food Safety
Austrian Agency for Food Safety
Österreichische Agentur für Gesundheit und Ernährungssicherheit GmbH
Spargelfeldstrasse 191
1220 Wien
Phone: +43 5 0555-0
Antonia Griesbacher works at the Austrian Agency for Food Safety in Vienna. The agency deals with the examination of food, the prevention and control of animal diseases and their transfer to humans. The agency also examines infectious diseases among humans, and the control of medicines and medicinal products. Griesbacher focuses, among other topics, on the use of antibiotics in Austrian pig farms and the consequences. She also looks at the occurrence of nematodes, like Trichinella, in Austrian pork products.
Germany
Uwe Rösler, Tier- und Umwelthygiene
Institut für Tier- und Umwelthygiene
Freie Universität Berlin
Robert-von-Ostertag-Str. 7-13
Raum 144
14163 Berlin
Phone: +49 30 8385 1830
Uwe Rösler is head of the institute for animal and environmental hygiene at Freie Universität Berlin. He is an expert in veterinarian epidemiology. He’s been a member of the International Society for Animal Hygiene (ISAH) since 2007, and from 2011 has been Germany’s representative to ISAH. He’s been a member of ISAH’s executive board since 2015. His research focuses on health and hygiene management in cattle and pig farming.
Annemarie Käsbohrer, Tierseuchen
Bundesinstitut für Risikobewertung
Abteilung Risikokommunikation
Fachgruppe Presse- und Öffentlichkeitsarbeit
Max-Dohrn-Str. 8-10
10589 Berlin
Postanschrift: Postfach 126942, 10609 Berlin
Phone: +4930 1 8412-0
In collaboration with her colleague Bernd-Alois Tenhagen, Annemarie Käsbohrer is in charge of epidemiology, zoonoses, and antibiotic resistance at the Bundesinstitut für Risikobewertung. She deals with resistance in livestock breeding and the influence of antibiotics on the foodchain.
Bernd-Alois Tenhagen, Tierseuchen
Bundesinstitut für Risikobewertung
Abteilung Risikokommunikation
Fachgruppe Presse- und Öffentlichkeitsarbeit
Max-Dohrn-Str. 8-10
10589 Berlin
Postanschrift: Postfach 126942, 10609 Berlin
Phone: +4930 1 8412-0
In collaboration with his colleague Annemarie Käsbohrer, Bernd-Alois Tenhagen is in charge of epidemiology, zoonoses, and antibiotic resistance at the Bundesinstitut für Risikobewertung. He deals with antibiotic resistance in livestock breeding and the influence of antibiotics in the foodchain. Since 2012 Tenhagen has argued that it is necessary to use antibiotics in a more responsible way in livestock breeding.
Lothar Wieler, Infektionsforschung
Institut für Mikrobiologie und Tierseuchen
Freie Universität Berlin
Robert-von-Ostertag-Str. 7-13
14163 Berlin
Phone: +49 30 838 51840
Lothar Wieler has been head of the Robert-Koch-Institut since 2015. He’s been an expert in the field of microbiology since 2007. He is also a professor at Freie Universität Berlin, where he managed the institute for microbiology and animal diseases before he became head of the RKI. In his research, Wieler focuses on zoonoses – germs that are transferred from animals to humans. These germs include the MERS-Coronavirus, the SARS virus, the Ebola virus and the hospital germ MRSA. He is particularly interested in mechanisms that help germs like E.coli to infect humans and animals alike.
Europe
Pierre Alexandre Beloeil, Lebensmittelsicherheit
Europäische Behörde für Lebensmittelsicherheit – EFSA
Via Carlo Magno 1A
43126 Parma (PR)
ITALIEN
Phone: +39 0521 036 833
Pierre Alexandre Beloeil is a senior officer in the department of biological hazards and contaminants at the European Food Safety Authority. The department focuses on the conditions which produce the existence of antibiotic resistant bacteria found in food and among animals. The EFSA regularly gives advice regarding responsible use of antibiotics in farming. Lately, EFSA has recommended reducing the use of the antibiotic Colistin in animals.
Netherlands
Dik Mevius, Epizootic Diseases
Faculty of Veterinary Medicine
Utrecht University
Androclusgebouw
Yalelaan 1
Room W 309
3584 CL UTRECHT
The Netherlands
Phone: +31 30 253 1099
Dik Mevius is Professor of Antimicrobial Resistance at Utrecht University. He started his career farm animal veterinarian, before specialising in large animal medicine at the University of Utrecht. During his PhD he focused on the impact of using antibiotics in livestock breeding, and the consequent resistant to antibiotics found in microbial organisms. At Wageningen University he founded an expert group that deals with antimicrobial resistance. He is also coordinator of the Dutch antimicrobial resistance and usage monitoring programme (MARAN). Furthermore, he works as an independent counsellor on antimicrobial resistance for the Ministries of Economic Affairs, Agriculture and Innovation, and Public Health.
Poland
Dariusz Wasyl, Epizootic Diseases
National Veterinary Institute
The National Veterinary Research Institute
57 Partyzantów Avenue
24-100 PUŁAWY
Phone: +48 81 889 3000
Dariusz Wasyl studied veterinary medicine and is the primary contact when it comes to antibiotic resistance in livestock breeding in Poland. He currently works at the Department of Microbiology in the National Reference Laboratory for Salmonellosis and Antimicrobial Resistance. He is particularly interested in the behaviour of resistant salmonella. He has conducted research aimed at implementing a system for monitoring antimicrobial susceptibility in E. coli. This research concentrates on Poland and provides an overview on E.coli, about the slaughtering process and the legal situation in the country concerning the use of antibiotics in livestock breeding.
Switzerland
Katrin Zurfluh, Food Safety
Institute for food hygiene and safety
University of Zurich
Winterthurerstrasse 272
CH-8057 Zurich
Phone: +41 44 635 86 51
Together with her team Katrin Zurfluh works at the Institut für Lebensmittelsicherheit und hygiene at the University of Zurich. Their research focuses on foodborne pathogens – bacteria that reach humans via the foodchain. The scientists research three things: the first concentrates on the characteristics, stress response, epidemiology, and behaviour of foodborne pathogens in relation to humans. The second is about the health hazards and monitoring systems on the microbiological level in the slaughtering process. In the third, the scientists deal with antibiotic resistance in microorganisms that are isolated from the meat and milk food chains.
Important Studies
MRSA from pigs now jumping from human to human in Denmark
In November 2013, a 63-year-old man with diabetes and end-stage kidney got fever because of inflammation. Samples of blood grew the resistant pig-bacteria, methicillin-resistant Staphylococcus aureus, MRSA, CC398. Three weeks later the man died.
By analysing the specific type of the bacteria, doctors identified the cause of the infection. It was another man. Someone carrying the same type of bacteria, staying in the same outpatient clinic at Odense University Hospital; a nasal and pharyngeal MRSA-carrier.
The dead man is proof that bacteria of animal origin now transmit directly between humans in Denmark. It does not need pigs anymore – but can jump directly from one human to another. The man from the Odense hospital is one out of two cases described May 2016 by Danish doctors in the journal Emerging Infectious Diseases.
New resistance against colistin
Colistin is an antibiotic that can cause strong side effects in humans. This is why it is only used as a last resort, when other antibiotics have been ineffective. Because it is used so infrequently, resistance has hardly developed.
But colistin has been used widely in farming. This wasn’t thought of as a problem, until scientists discovered that resistance had developed. At first, because the resistance gene was found on a non-mobile part of the bacterial DNA, it was thought that the resistance could not be transferred from one bacteria to another. But Chinese scientists became suspicious after observing the spread of resistant germs in pig farms. Could resistance be transferred from germ to germ after all? Yes. The scientists collected samples and discovered a resistance gene located on a mobile part of the DNA. They called it mcr-1.
Since then the resistant gene has been found in other countries, as well as in humans. The discovery has spurred debate over whether the use of colistin in farming should be reduced.
Disinfectants can lead to resistances
Disinfectants can also lead to antibiotic resistance, according to scientists led by Mark Webber at the University of Birmingham. They treated the typhus germ Salmonella typhimurium with different disinfectants. The result was the emergence of bacterial strains immune to the disinfectants. These strains were also resistant to antibiotics.
The reason for this was the bacteria had acquired molecular pumps that expel the disinfectant, and antibiotics, from the bacterial cell. The results should encourage frugal use of disinfectants, especially at home, where there is hardly any evidence for their effectiveness.