Agriculture and Antibiotics: Trying to Protect the Former and Preserve the Latter

One of the ongoing, major issues associated with antimicrobial resistance is that massive amounts of antibiotics are used in agriculture. In 2020, approximately 160,000 tons of antibiotics were fed to farm animals in the United States alone.

Along with the sheer numbers that the agricultural industry is utilizing, the other aspect is the potential misuse, which can lead to resistance. A majority of the time, antibiotics are administered indiscriminately through animals’ feed and water supplies.

According to the FDA’s 2019 summary report on Antimicrobials Sold or Distributed for Use in Food-Producing Animals, the domestic sales and distribution of medically important antimicrobials approved for use in food-producing animals for 2019 included:

• “An estimated 41% was intended for use in cattle, an estimated 42% intended for use in swine, an estimated 10% intended for use in turkeys, an estimated 3% intended for use in chickens, and an estimated 4% intended for use in other species/unknown.
• Tetracyclines accounted for 67%, penicillins for 12%, macrolides for 8%, sulfas for 5%,aminoglycosides for 5%, lincosamides for 2%, cephalosporins for less than 1%, and fluoroquinolones for less than 1%.
• An estimated 81% of cephalosporins, 65% of sulfas, 45% of aminoglycocides, and 42%of tetracyclines were intended for use in cattle.
• An estimated 85% of lincosamides and40% of macrolides were intended for use in swine. An estimated 66% of penicillins were intended for use in turkeys.”

“We can't just stop farming without antibiotics tomorrow, because we still have to eat every day and without antibiotics, food prices would go up, and productivity would go down,” said Jen Ronholm, PhD, associate professor, McGill University and Canada research chair in agricultural microbiology. “We'd have shortages of a lot of things that we need. So, it's really bridging that gap to come up with the novel technologies that don't currently exist to be able to farm effectively and not affect human health through over consumption of antibiotics.”

Looking for novel ways to reduce antibiotics in the agricultural industry has been an area of focus for Ronholm. She has been studying the microbiome and how it can help reduce the need for antibiotics in animals.

“What we're trying to do is come up with ways that we can still farm effectively without using those antibiotics,” Ronholm said. “And we're trying to do this through manipulating the microbiome of animals so making it really resist to infections so we don't need those antibiotics in agriculture, and that would have the effect of lowering usage and saving the antibiotics for human use.”

Ronholm says she and her coinvestigators are looking to identify what a “healthy” microbiome is, and what a microbiome that might be susceptible to bacterial infections looks like. They are exploring down to the species level, which means they are looking to identify members of the microbiome that are protective against different types of infection so that these bacteria can be investigated as potential probiotics to prevent these types of infections.

In humans, studies have been ongoing looking at the gut and how the microbiome can affect overall health. One area of study has been around the microbiome and treatment for C difficile. And newer therapies using this concept have been FDA approved to help patients with recurrent bouts of the infection.

At this week’s World AMR Congress, Ronholm made a presentation titled, Precision Microbiome Engineering as an Alternative to Antibiotics to Prevent Bacterial infections in Agriculture. She sat down with Contagion to discuss her ongoing work in this area.

She believes there is a lot of potential to understanding the microbiome in agriculture with better benefits.

“It has a lot of potential in agriculture, specifically because you control everything about the animals: you control their environment, you control their food. So, it might actually be more effective in agriculture than in humans.”