Ever since the FDA issued its Draft Guidance 213 and the proposed Veterinary Feed Directive (VFD) rules in 2013, veterinarians and industry stakeholders have wondered about measurement.

The FDA rules of course, are intended to encourage judicious use of antimicrobials and thus reduce the risk of development of antimicrobial resistance in pathogens, and the industry generally has supported this effort. But, many have asked, how will we know whether the rules, once implemented, have any positive impact? Will the industry be able to measure and report significant reductions in antibiotic use or lower prevalence of resistant pathogens?

During the recent National Institute for Animal Agriculture (NIAA) conference in Indianapolis, the NIAA Antibiotics Council discussed program goals and metrics with officials from the FDA and USDA.

Craig Lewis, DVM, MPH, DACVPM, from FDA’s Center for Veterinary Medicine (CVM), says the agency sees a need for collecting more on-farm data on antibiotic use and resistance trends, and is currently developing a plan for collecting, analyzing and applying that data.

Currently, FDA cooperates with the USDA and the Centers for Disease Control and Prevention (CDC) in the National Antimicrobial Resistance Monitoring System (NARMS), and also collects data on total sales of antimicrobials for use in animals. More data will be needed to augment those efforts and determine the effectiveness of FDA’s strategy for judicious use of antimicrobials.

That strategy focuses on two primary policies. First, Guidance 213 aims to eliminate use of medically important antimicrobials for production or performance purposes in livestock. In addition, FDA intends to require veterinary oversight of the use of antimicrobials in feed and water through the proposed VFD rule.

In 2014, Lewis says, CVM substantially enhanced its annual survey on the quantity of antimicrobials sold for use in animal agriculture. Addition of on-farm use and resistance data, coupled with data currently collected through NARMS, will provide information for assessment of the impacts of the judicious use strategy.

The FDA initiated their strategy in December 2013, with a three-year timeline for implementation. They have indicated they will finalize the proposed VFDrule early this year. Also early this year, Lewis says CVM plans to hold a public meeting to discuss the on-farm data-collection strategy to support the judicious use strategy. By later this year, CVM hopes to have the data-collection plan in place and begin collecting baseline data, prior to full implementation of Guidance 213 and the VFD rule in December 2016. By late 2016 and into 2017, with the changes in antimicrobial use fully implemented, CVM plans to implement its data collection and comprehensive assessment of antimicrobial use and resistance trends. Lewis says CVM intends to publish its first assessment report showing changes in antimicrobial use in 2018.

USDA also will play a role in assessing progress in fighting antimicrobial resistance, and Larry Granger, DVM, senior leader for Veterinary Services (VS) at the USDA’s Animal and Plant Health Inspection Service (APHIS), outlined his agency’s perspectives during the conference.

Granger noted that antimicrobial resistance is a high priority for the Obama administration, which recently introduced a report on Combating Antibiotic Resistance, along with an executive order, based on the recommendations of the President’s Council of Advisors on Science and Technology (PCAST).

Among stakeholders outside of agriculture, Granger says, many believe the health risks associated with antimicrobial resistance are best resolved by reducing use. However, he says, data on antimicrobial sales alone are a poor indicator of actual use across production types and livestock species.

Also, Granger points out, the VFD rule is not designed to limit appropriate use of antimicrobials. Instead, by increasing veterinary oversight, the rule should help ensure the right drugs are targeted toward appropriate pathogens at the correct dosages, with treatment records and results recorded.

Granger says USDA, like FDA, advocates collection and dissemination of more science-based, actionable, quantitative antimicrobial use data coupled with information on resistance trends. His agency’s National Animal Health Monitoring System (NAHMS) could be enhanced to conduct more epidemiological work to correlate use patterns with resistance. And he adds, the cooperative NARMS program could be enhanced to conduct biological sampling on farms or slaughter plants, with tests for antimicrobial sensitivity then related back to farm practices.