Antibiotics in Animal Agriculture: What You Need to Know

Globally, increasing acquired antimicrobial resistance (AMR) among pathogenic bacteria presents an urgent challenge to human and animal health. As a result, significant efforts, such as the One Health Initiative, are underway to curtail and optimize the use of critically important antimicrobials for human medicine in all applications, including food animal production. This review discusses the rationale behind multiple and competing “critically important antimicrobial” (CIA) lists and their contexts as created by international, regional, and national organizations; identifies discrepancies among these lists; and describes issues surrounding risk management recommendations that have been made by regulatory organizations on the use of antibiotics in food animal production. A more harmonized approach to defining criticality in its various contexts (e.g., for human versus animal health, enteric diseases versus other systemic infections, direct versus indirect selection of resistance) is needed in order to identify shared contextual features, aid in their translation into risk management, and identify the best ways to maintain the health of food animals, all while keeping in mind the wider risks of AMR, environmental impacts, and animal welfare considerations.

Antimicrobial resistance (AMR) is a significant threat to both human and animal
health. However, the spread of AMR bacteria and genes across systems can occur via
through a myriad of pathways, both related and unrelated to agriculture, including
via wastewater, soils, manure applications, direct exchange between humans and
animals and food exposure. Therefore, tracing origins and drivers of AMR bacteria
and genes is challenging due to the array of contexts and complexity of interactions,
which overlaps health practice, microbiology, genetics, applied science and engineering,
and also social and human factors. As such, critically assessing the diverse and sometimes contradictory AMR literature is a valuable step in identifying tractable mitigation options to stem AMR spread. This
article reviews research on the non-foodborne spread of AMR with a focus on
domesticated animals and the environment, and possible exposure risks to humans.
Attention is especially placed on delineating possible sources and causes of AMR
bacterial phenotypes, including underpinning genetics important to human
and animal health.

In an effort to reduce the use of antibiotics in animal agriculture, a number of
effective or commercially viable alternatives have been implemented by food animal
producers or are under development. Perhaps the most well-established strategies
are flock and herd management practices to mitigate disease introduction and
spread and, subsequently reduce the need for antibiotic use. Vaccines in food animal
production have been used to prevent bacterial and viral diseases, but
historically, most have targeted viral diseases.

Though vaccines against viral diseases can help reduce the need for antibiotic
use by controlling the spread of secondary bacterial infections, more recent vaccines
under development specifically include bacterial targets. New developments in
selecting and potentially tailoring bacteriophages also provide a promising avenue
for controlling pathogenic bacteria without the need for traditional small-molecule
antibiotics. This article will discuss these established and emerging strategies, which
are anticipated to reduce the reliance on antibiotics in food animal production and
should reduce the prevalence and transmission to humans of antimicrobial resistant
bacteria from these systems.

Assessing the risk of a consumer acquiring an antimicrobial resistant (AMR) infection from foods of animal origin is difficult due to a number of factors that must co-occur. Consequently, communicating risks regarding food safety and AMR to consumers remains an important yet challenging priority. Consumers are bombarded with negative or unclear messages on animal product labels, such as no antibiotics ever (NAE) or hormone free. These labels can lead to confusion about which product is healthier for people, the animals, and the environment. Studies have shown that consumers are interested in learning more about the products they purchase and about AMR infections. This article will discuss some of the efforts that are currently underway to create more meaningful labels and to better communicate with consumers regarding the uncertainty associated with foods of animal origin and AMR.