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Antimicrobial Resistance Overview (AMR)

World Antimicrobial Awareness Week 2021 Infographic (PDF, 378 KB)

USDA’s Role in Addressing Antimicrobial Resistance

The United States Department of Agriculture (USDA) is responsible for protecting American agriculture and the American food supply. One of the many ways USDA does this is by addressing antimicrobial resistance (AMR).

What is AMR?
The petri dishes show sterilization effects of negative air ionization on a chamber aerosolized with Salmonella enteritidis. The left sample is untreated; the right, treated

AMR is a natural process in which bacteria continually evolve to resist and survive substances that should kill them, whether these substances are produced by the environment, other bacteria, fungi, other microbes or are antibiotics developed by people. AMR bacteria are everywhere–intimately linked with humans, soils, plants, and in food-producing and companion animals. One important aspect of AMR is that some bacteria develop resistance to antibiotic drugs, resulting in loss of effectiveness of those drugs.

Many human activities such as medical and veterinary treatments or disposal and transport of human sewage and animal waste can affect the number and kind of resistant bacteria in people, animals, and the environment.

Antimicrobial treatments are used to help sick human and animal patients overcome their illnesses and to help prevent the spread of diseases. Bacteria can develop a resistance to these treatments, which makes them less effective. To reduce the chances for development of antimicrobial resistance, we need to be careful with how and when we use them.

Read more: USDA describes the work it does to address AMR in its USDA AMR Action Plan (PDF, 322 KB)

What does USDA do to address AMR?

USDA works alongside many others to limit AMR. Here are some ways we address AMR every day:

USDA Protects Public Health

  • Research AMR in bacteria in agricultural settings that may affect humans
  • Conduct monitoring and surveillance and improve epidemiological methods in foodborne illness investigations
  • Collaborate with and inform public health agencies, including the Centers for Disease Control and Prevention and the Food and Drug Administration
  • Participate in foodborne outbreak investigations with public health partners
    U.S. Department of Agriculture Supervisory Agricultural Commodity Graders (Meat) correlate on beef at their annual national beef correlation event

USDA Protects the Meat Supply

  • Test meat and poultry for AMR bacteria and antimicrobial residues
  • Inspect slaughter/processing plants for safe practices and ensure that food is safe, nutritious and wholesome
  • Research ways to improve best management practices to reduce AMR in agricultural settings
  • Evaluate management practices to optimize animal health and reduce the need for antimicrobials

USDA Evaluates Antimicrobial Use in Livestock

  • Conduct surveys of animal health, including antimicrobial use
  • Research how animal management can affect antimicrobial use
  • Develop alternatives to antibiotics in food producing animals

USDA Collaborates with Others to Share Information and Leverage Resources

  • Collaborate with the private sector, non-governmental organizations, commodity and industry organizations, universities and State and Federal agencies
  • Partner with countries to share technical information and enhance the capacities of governments, non-governmental organizations, academia, and the private sector
  • Coordinate within international organizations on science and risk-based activities to understand antimicrobial use and resistance and develop guidance
  • Work with industry and the other Federal and state partners to reduce pathogens and AMR in foods


What is the relationship between antibiotic use in agriculture and AMR bacteria?

Antibiotic use on farms and AMR bacteria found in food do not have a one-to-one relationship. While some believe antibiotic use in agriculture is one of the primary drivers for AMR emergence, the fact is we have an incomplete understanding of the factors that contribute to AMR in various settings.

USDA Agricultural Research Service (ARS) and National Institute of Food and Agriculture (NIFA) projects on farms, in fields, and at processing facilities are developing a much more refined understanding of how and why resistant bacteria evolve and how they become present in our food production systems. Such studies show how complicated AMR actually is, especially as we try to understand how it occurs in systems as big in size and diverse in purpose as livestock and poultry production, crop production and food processing.

Protecting public health and the integrity of the food production system is USDA’s priority. Our work is focused on developing a science-based understanding and solving actual risks of AMR in agriculture: how to keep the food supply safe, rather than simply focusing on where AMR bacteria can be found. AMR bacteria are found everywhere in nature so we must focus on how that translates to real risks.

ARS researchers have found that cattle raised with standard practices and those raised without antibiotics have similar levels of resistant bacteria. In another study, when manure from beef cows was added to soil plots, the levels and types of resistant bacteria were very similar to that found in soil plots that only nutrients such as sugar had been added.

For more information about these studies, see:

How does the amount of antibiotics used in food animals in the United States compare to the amount used in other countries?

Comparisons of antibiotics used or sold between countries are often inaccurate and can be misleading.

  • Sometimes comparisons are made between antibiotic sales and antibiotic use data. “Use” and “sales” data are not the same. Further, differences in animal populations, weights, and production practices differ between countries and can influence results. For more information, please read FDA Releases Annual Summary Report on Antimicrobials Sold or Distributed in 2019 for Use in Food-Producing Animals.
  • Ionophores are a class of antibiotics that are only used in animals and are not known to promote resistance to antimicrobials of human importance. Ionophores account for 37% of the total U.S. antibiotic sales reported in 2019. In many countries, ionophores are used, but not regulated as antibiotics and not included in antibiotic sales or use totals.
  • Estimates of antibiotic use are difficult to calculate and there is no global “gold standard” for such a metric. For more information on antibiotic use in food animal sectors in the United States see the special issue of Zoonoses and Public Health which highlights the findings from on-farm pilot studies.
Is meat from animals that have never had antibiotics free from AMR bacteria?

The short answer is no. This is because regardless of whether or not an animal is treated with antibiotics, bacteria including those that may be resistant to certain antibiotics may be present on raw meat. Proper cleaning, separating, cooking, and chilling are always necessary.

Does meat from animals that were treated with antibiotics contain antibiotic residues?

FSIS-regulated meat and poultry is regularly tested for antibiotic residues under the National Residue Program. This comprehensive regulatory program ensures the safety of U.S. meat, poultry, and egg products, by inspecting, testing and ensuring that harmful residues are not present in these products.

You may visit the FARAD website to find out more about residues.

The terms antibiotic resistance and antibiotic residues can sometimes be confusing although these have distinctly different meaning. This is explained in the FSIS AMR Q/As. The FSIS animal raising claims and labeling guidelines can provide more information on product labels.

What do labels about antimicrobial use mean? View the Livestock and Poultry Auditing & Verification page to see more about labeling.

Is AMR increasing?
Salmonella typhimurium bacterium

There isn’t a simple yes or no answer to this question. Resistance trends need to be evaluated by bug-drug-species combinations rather than simply stating that all resistance is increasing or decreasing.

Data from the most recent NARMS Integrated Report (PDF, 7.9 MB) shows that 28.1-45.7% Campylobacter isolates (C. coli and C. jejuni) and 76.2-84.8% non-typhoidal salmonellae were susceptible to antimicrobials tested from 2006-2015 in humans. Multidrug resistance in salmonellae in beef in the U.S. has been declining.

If any use of antibiotics can lead to AMR, why are antibiotics used in animal agriculture?

Animals get sick sometimes, just like people do. Veterinarians can treat bacterial diseases in animals with antibiotics. For example, recently weaned piglets are susceptible to respiratory disease and diarrhea. Veterinarians can administer antibiotics to piglets in feed or water to treat these illnesses and reduce unnecessary suffering.

Antibiotics are just one of the tools producers use to address animal disease on their farms and ranches. They also prevent or address diseases by following strict biosecurity practices, having a vaccination program, and following an early disease detection plan.

The USDA National Animal Health Monitoring System conducts periodic studies of animal agriculture and routinely collects information about antibiotic use and stewardship practices on farms.

For more information about these studies, see:

USDA Activities

USDA relies on sound science and risk-based approaches in its decision-making. Activities focus on:

  1. monitoring and surveillance;
  2. research and development; and
  3. education, and outreach.

These activities help determine patterns of antibiotic use in food producing animals; monitor antibiotic drug susceptibilities in food animals, meat and poultry; and develop mitigations to reduce AMR associated with food producing animals and their production environments. The Collective Antimicrobial Resistance Ecosystem diagram (PDF, 54.1 KB), shows how human and animal ecosystems are interconnected under the "One Health" concept. Detecting and controlling antibiotic resistance requires the adoption of a "One-Health" approach to disease surveillance that recognizes that resistance can arise in humans, animals and the environment.

The findings and gaps identified in a USDA-sponsored workshop in May 2012 were used to help develop the USDA Antimicrobial Resistance (AMR) Action Plan (PDF, 322 KB), which summarizes ongoing activities as well as articulates USDA's vision for an integrated plan to enhance USDA efforts to address AMR.