Antimicrobial-resistant bacteria in animal production

7 min readJul 5, 2020


Text by Edona Emilie Arnesen, Head of Produce at Dagens

The complex intertwining of animals, humans and the environment

Illustration: The Lancet One Health Commission

Antimicrobial resistance (AMR) is the broader term for resistance in different types of microorganisms and encompasses resistance to antibacterial, antiviral, antiparasitic and antifungal drugs.

In industrial animal production around the world — the production of livestock for food purposes — the use of antibiotics is devastatingly high. One reason is for the treatment of sick animals, but antibiotics are also routinely used as a preventive method due to the intensive production operations, in addition to as growth promoters. The high use of antibiotics in livestock, often as low doses over a longer period of time, contributes to the development of antimicrobial-resistant bacteria.
The WHO has already been warning about this being a problem for some time, making strong recommendations on how to change practices in animal production to combat the very real problem of antimicrobial resistance that we are seeing globally.

There is a substantial consistency across studies showing that a reduction in antibiotic use in animal production reduces the prevalence of antimicrobial-resistant bacteria in these animals. Several studies comparing the prevalence in organically versus conventionally produced livestock show that though the animals may have the same amounts of bacteria, the organically produced animals have far less of them resistant to antimicrobials.

It is not only the volume of antibiotics that matter when it comes to the development of resistance. The reasons behind the high volume-use of antibiotics in intense animal production systems are also important to highlight. In Concentrated Animal Production Operations (CAFO) as intensive livestock production is often called, the intensity of antibiotic use is often greater due to challenges associated with hygiene and infection control in the setting of very high animal density[1]. Animals get vulnerable and sick more often because of their contaminated and stressful living conditions, driving up antibiotic usage in the whole flock or herd, because they do not get individually treated.

Photo: Darcy Maulsby

Why is this important?

Many bacteria carried by animals can also cause disease in people. Studies show that bacteria in livestock are frequently antimicrobial-resistant and can cross-contaminate to humans through direct contact, food and the environment [2]. Animals, like people, carry bacteria in their guts which may include antimicrobial-resistant bacteria. When animals are slaughtered and processed for food, resistant germs in the animal gut can contaminate meat or other animal products. Animal fecal matter also carries resistant bacteria, as 75–90% of antibiotics get excreted mostly un-metabolized. Fruits, vegetables, and other produce can become contaminated through contact with soil or water containing fecal matter from animals, as irrigation with wastewater is common practice in many countries around the world, as well as spreading manure on fields.

Most of the developed world has effective wastewater treatment for human wastes, but 73% of the world has no major waste treatment. Even less so for livestock. Alas, massive amounts of untreated animal fecal matter enter the environment with the potential of contaminating food and water, threatening public health [3].

Some type of bacteria that cause serious infections in humans are already resistant to all the available treatments we have, according to WHO. Their recommendations to reduce overall use of antibiotics in animal production are made to help preserve the effectiveness of antimicrobial treatments of humans, as the same type of antibiotics are often used for both segments [5].

Valuable insights on AMR from the Covid-19 pandemic

Covid-19 is a virus, not a bacterial infection, and the contamination and treatment of it is therefore not directly linked to antibiotic resistance. However, the outcome of a disease like this is seemingly very much dependent on the risk of secondary infections by antimicrobial-resistant bacteria with possibly fatal consequences. If you are infected by the Covid-19 virus you have a fair chance of recovering well, but if you are additionally infected by a bacterial infection which is untreatable because antibiotics are non-functioning, you could end up in a very severe situation when your immune system is already compromised.

Scientists and doctors are now debating the importance of antimicrobial-resistant bacteria in the high death rates in Italy and Spain (as examples) during the Covid-19 pandemic. In primary medicine in Italy, the use of antibiotics is almost double the amount of that in Norway. In animal production, the situation is even worse. Tons of antibiotics are pumped into millions of pigs yearly, to secure the Italian cured meat production, among others. The situation is similar in Spain, arguably spiking the pandemic death rates and collapse of the health care system.

In May 2020, the scientific journal Nature Microbiology wrote that it is imperative that we understand the pathogenesis of infection from Covid-19 and the potential for bacterial coinfections. Until we do, efforts to prioritize global antibiotic stewardship must be redoubled [4].

Soil, manure and food production

Healthy soil is a vital living system essential for crop agriculture. Important components for healthy soil include organic matter and microbes, including bacteria and fungi. Organic matter provides food for microbes, stabilizes soil structures, and increases soil fertility. In agricultural systems, manure is often applied to fields as an additional source of organic matter. However, manure almost certainly contains microbes that include antibiotic-resistant bacteria” (Graham et. al) [3].

The last sentence is true for most of animal production but is also influenced by what kind of production method the manure comes from. If the animals are raised with adequate space, natural fodder and no preventive or growth-promoting antibiotics, their manure will be a healthy and important input in agricultural production — not one that causes more damage than good. Composted animal manure is black gold for competent farmers, and an asset that reduces or mitigates the need for buying inorganic fertilizer from outside the farm system, securing a more balanced farm economy.

Photo: Eirik Røed / Ren Mat

What now?

The way food is produced — in this case the production of animals for food — has extreme implications for the health of the animals, humans, the environment and nature’s ecosystems. We need to produce food in a way that secures the health of this delicate and intertwined system where everything is intricately linked. In order to do so, consumers have to request sustainably, consciously and ethically produced food and take a clear stand. Money speaks, and we need to vote with both our economic choices and our political votes.

We must buy and eat meat from animals that have been taken care of by competent farmers with empathy for their animals, and we have to be prepared to pay more for our food for it to be healthy. We must eat meat from animals who have had adequate space for roaming, the ability to act out their natural behavior and who have eaten natural, local food in an environment free from antibiotics. Eating less meat is also important, as we are not able to produce the amounts of livestock needed for the modern meat-eater if we are to do it in a sensible way.

We have still not learned well enough that antimicrobial resistance is a global problem, though Covid-19 has had us understand more about the severity of the situation. We need more global cooperation now that we see how quickly disease travels the globe. This cooperation needs to include strict demands on approved levels of antibiotics use in animal production, and better systems of tracing regarding the spreading of antimicrobial-resistant bacteria.

On a systemic scale we need political and economic systems that support organic and regenerative food production with a focus on good animal welfare, natural recycling of nutrients within food production systems, composting of animal manure to be used as natural, nutrient-dense fertilizer (from animals not fed with antibiotics), and higher taxes on food produced in harmful ways as described in this article.

[1] Morel, C. (2019–07–10), “Transmission of antimicrobial resistance from livestock agriculture to humans and from humans to animals”, OECD Food, Agriculture and Fisheries Papers, №133, OECD Publishing, Paris.

[2] Restricting the use of antibiotics in food-producing animals and its associations with antibiotic resistance in food-producing animals and human beings: a systematic review and meta-analysis, Lancet Planet Health, 2017 Nov; 1(8): e316–e327.

Karen L Tang, MD,a Niamh P Caffrey, PhD,b Diego B Nóbrega, PhD,c Susan C Cork, Prof, PhD,b,d Paul E Ronksley, PhD,d,e Herman W Barkema, Prof, PhD,c,d,e Alicia J Polachek, MA,f Heather Ganshorn, MLIS,g Nishan Sharma, EdD,e,f James D Kellner, Prof, MD,d,h,i and William A Ghali, Dr Prof, MDa,d,e,*

[3] Complexities in understanding antimicrobial resistance across domesticated animal, human, and environmental systems, Ann N Y Acad Sci, 2019 Apr; 1441(1): 17–30.

David W. Graham,1 Gilles Bergeron, 2 Megan W. Bourassa, 2 James Dickson, 3 Filomena Gomes, 2 Adina Howe, 2Laura H. Kahn, 4 Paul S. Morley, 5 H. Morgan Scott, 6 Shabbir Simjee, 7 Randall S. Singer, 8 Tara C. Smith, 9Carina Storrs, 10 and Thomas E. Wittum 11

[4] Antimicrobial resistance in the age of COVID-19. Nat Microbiol 5, 779 (2020).

[5] Antimicrobial resistance in the food chain, WHO, November 2017.




Direct trade from farm to kitchen. Co-creating a transparent and resilient food system. Live in Denmark and Norway.