A private practice teams up with the USDA to study drug use, resistance

Collaborators to analyze data from client farms

Veterinarians are tracking antimicrobial administration and drug resistance in millions of pigs in a first-of-its-kind collaboration between the federal government and a private veterinary practice.

Veterinarian and researcher Dr. Scott Dee said the data collection from swine herds is for a long-term project to understand the role of antimicrobial administration in selection for drug resistance. Dr. Dee is director of applied research for Pipestone, which is a veterinary services, research, and farm management company based in Pipestone, Minnesota. The farms participating in the collaborative project are Pipestone clients, which are providing access to data from 160 sites housing swine.

Dr. Dee said Pipestone is helping fund the project, and he and his colleagues intend to publish and share the results.

Dr. Taylor Spronk at work in a swine barn
Dr. Taylor Spronk, a veterinarian with Pipestone, co-leads a collaboration with the U.S. Department of Agriculture to collect and analyze data on antimicrobial administration and drug resistance from swine farms. (Courtesy of Pipestone)

“Our duty as veterinarians is to go out and scientifically collect good data and make good conclusions to really start evaluating the relationship of use and resistance,” Dr. Dee said. “That’s just being a good steward of antibiotics.”

The U.S. Department of Agriculture announced the partnership Nov. 30, 2021, hailing the collaboration as a potential model for future studies to monitor antimicrobial use and resistance. The announcement indicates Pipestone is collecting and sharing anonymized data with the USDA Animal and Plant Health Inspection Service’s National Animal Health Monitoring System.

APHIS officials hope to publish initial results sometime in 2022.

In response to questions, APHIS spokesperson Joelle R. Hayden provided a written statement from APHIS leaders on the project. They wrote that the project is a unique collaboration among APHIS, the private veterinary clinic of Pipestone Veterinary Services, and South Dakota State University’s Animal Disease Research and Diagnostic Laboratory, with financial support from the National Pork Board and the antimicrobial stewardship consortium within the Foundation for Food and Agriculture Research.

“This is the first time that the federal government, producers and veterinarians, and the swine industry have partnered on addressing antimicrobial resistance,” APHIS officials said. “This is exciting because it provides valuable context to the discussion on use and resistance.”

The project has already shown that monitoring antimicrobial use and resistance on a farm requires ample resources and expertise, APHIS officials said.

“Outcomes of this study will hopefully identify key pieces of information to monitor for the swine industry,” they said.

Dr. Dee said he hopes the study will last at least five years, which would give time to collect and analyze enough data to measure changes in antimicrobial administration and antimicrobial resistance.

The APHIS officials noted that, while the agency is on an annual funding cycle, the project collaborators were in their second year of data collection, and they had funding for the third. The project also aligns with previous commitments to understand development of antimicrobial resistance and prolong the effective use of antimicrobials, they said, citing the Antimicrobial Resistance Action Plan published by APHIS in 2014.

In October 2021, the National Academies of Sciences, Engineering, and Medicine published a report containing a series of recommendations for combating antimicrobial resistance to protect human, animal, and environmental health. The authors—from the Committee on the Long-Term Health and Economic Effects of Antimicrobial Resistance in the United States—called for a global response that is modeled on the President’s Emergency Plan for AIDS Relief, which they noted is a program that has invested $85 billion toward fighting the HIV epidemic since 2003.

The report also contains recommendations that the Food and Drug Administration Center for Veterinary Medicine determine how to track antimicrobial administration to animals and produce data that could support stewardship programs. The authors also recommend that agency officials convene experts who can help coordinate development of testing breakpoints for whether pathogens in animals are susceptible to antimicrobials and identify priority animal, drug, and pathogen combinations.

Further, the report notes that vaccines could reduce demand for antimicrobials in animal agriculture. It notes that the AVMA has identified pathogens of concern in animal species raised as pets or food, and the World Organisation for Animal Health has identified priority diseases and pathogens in poultry, swine, and fish.

“These lists are a good starting point for research and development efforts in animal vaccines,” the report states.

Antimicrobial sales on farms remained down in 2020

The amount of antimicrobials sold for use on farms remains down in the four years since federal regulators added limits on access to drugs and how they are used.

At the start of 2017, Food and Drug Administration officials implemented restrictions on antimicrobials that are administered to animals in feed or water and are considered “medically important” because they are in drug classes shared with human medicine. The agency did so in a series of agreements with drug companies to modify drug approvals to remove over-the-counter access to those products and remove approvals for production uses, such as growth promotion.

The FDA’s most recent data show that the volume of those drugs, by weight, sold for use in food-producing animals dropped about 28% from 2016-20, and that includes a 3% decline from 2019-20, according to an agency report published in December. The sales volume for antimicrobials considered medically unimportant—primarily ionophores—also declined about 22% during that time, and most of that difference was from a 16% drop from 2019-20.

The FDA Center for Veterinary Medicine outlines the changes in the 2020 Summary Report on Antimicrobials Sold or Distributed for Use in Food-Producing Animals, which contains sales data since 2011.

The report indicates that, of the medically important drugs, about 41% of the volume was intended for administration to cattle, another 41% to swine, 12% to turkeys, 2% to chickens, and 4% to other or unknown species. The volumes sold in 2020 were about 13 million pounds of medically important antimicrobials and 10 million pounds of medically unimportant antimicrobials.

The data have some limitations. They show, for example, volumes sold but not the volumes administered. And the report notes that the potency of antimicrobials can vary substantially.

The AVMA provides practical resources for veterinarians on antimicrobial to use in practice as well as definitions of and policies related to antimicrobials and antimicrobial resistance.

A version of this article appears in the Jan. 15, 2022, print issue of JAVMA.