The total amount of animal antibiotics sold in the United States for use in food producing animals dropped 33 percent in 2017, according to annual data released Dec. 18 by the Food and Drug Administration.
The data for 2017 reflect antibiotic sales for the first year that critical new FDA rules for use of medically important antibiotics in animal agriculture were in full effect. FDA’s Guidance for Industry (GFI) 213 prohibited the use of medically important antibiotics as growth promoters and brought their use in feed and water under veterinary oversight.
Antibiotics sold for use in animal feed experienced the sharpest decline—43 percent from 2016—while the decrease for those used in water was a more modest 14 percent. Sales of antibiotics administered by routes not affected by GFI 213—such as by injection or direct administration into the udder—essentially remained flat and accounted for about 10 percent of all medically important antibiotics sold. Many of the drugs still lack appropriate veterinary oversight, an issue that FDA has committed to resolve as part of its five-year plan.
This is also the second consecutive year that animal drug companies have broken down sales estimates by the major types of food animals—pigs, cows, chickens, and turkeys. Encouragingly, the downward trend is seen across all of them. In addition, the data begin to shed light on species-specific use patterns. For example, 60 percent of penicillins in 2017 were used in turkey, 72 percent of sulfonamides were used in cattle, and 84 percent of lincosamides were used in swine. This type of information will help identify lessons learned, target interventions, and prioritize funding for research into nonantibiotic alternatives, all of which are important to strengthening antibiotic stewardship in food animal production.
The species-specific data can provide critical insight because multiple years of such information allow trends in use patterns to emerge. For instance, the use of macrolides in swine decreased 44 percent from 2016, and the use of tetracyclines in cattle dropped 45 percent. The World Health Organization considers both of these antibiotics important for human medicine, with macrolides seen as critically important. Minimizing the use of medically important antibiotics is essential because their use in any setting—including in animal agriculture—contributes to the emergence of bacterial resistance.
While the data show that important progress has been made, they only capture quantities of antibiotics sold and not actual use. FDA must rely on industry estimates of which species were given the drugs, and the information does not include enough detail to determine why the antibiotics were used. Differences in specific populations, such as the animals’ size and number, also make the current data hard to interpret and compare.
A recent FDA proposal to establish a method for estimating the size of the animal populations potentially being treated with antibiotics could help put the species-specific sales numbers in context. In its five-year plan, FDA called out these limitations and committed to incorporate biomass adjustments into sales data and to improve current antibiotic use and resistance surveillance systems, such as the National Antimicrobial Resistance Monitoring System.
The new data on antibiotic sales are encouraging and provide crucial insight into how these important drugs are used in U.S. agriculture, but more remains to be done. FDA needs to swiftly implement its five-year plan to enhance stewardship and improve the data available to measure successful implementation of these valuable policies. The Pew Charitable Trusts looks forward to continuing to work with FDA and other stakeholders to improve antibiotic stewardship in food animals as part of the broader effort to combat resistant bacteria.
Karin Hoelzer works on The Pew Charitable Trusts’ safe food and antibiotic resistance projects and is a veterinarian by training. Daniel Feingold works on Pew’s antibiotic resistance project.