During last week’s conference on antibiotic use and resistance, hosted by the National Institute for Animal Agriculture (NIAA) in Kansas City, Mike Apley, DVM, PhD, a professor at Kansas State University, discussed the current state of antibiotic use and resistance in animal agriculture, and the importance of a true commitment to judicious use.

The years between 1935 and 1978 featured rapid development of new classes of antibiotics, but in recent years that development has slowed, increasing the importance of protecting the efficacy of existing products.

Apley acknowledges that antibiotic use in food animals can change bacteria susceptibility profiles, leading to resistant pathogens that can be transferred through the food chain or through contact with animals. Documented cases of antibiotic resistance in pathogens affecting humans, linked to animal agriculture, and cases of reduced effectiveness of antibiotics for treatment of animal disease, such as bovine respiratory disease from Manheimia haemolytica, necessitate a close look at current practices.

Ionohores, which have no application in human medicine, account for about 29 percent of the total volume of antimicrobials used in animal agriculture, Apley says. Tetracyclines account for about 42 percent of the total and about 64 percent of the medically important antibiotics used in animal agriculture. Most of that use in livestock is for treatment of disease, with smaller percentages for disease prevention or for production purposes. Apley says veterinarians and the industry need to continuously evaluate whether particular uses of specific products are effective and necessary, and if not, reconsider those uses.

Apley outlined guidelines for judicious use, including:

  • Use an antimicrobial product when there is not an effective alternative for the treatment or prevention of disease.
  • Use the antibiotic based on evidence it will be safe and effective for that use.
  • Maintain a commitment to administer antibiotics according to a regimen demonstrated to be safe and effective. Apley notes, however, that research-based evidence for optimum dosing and duration of treatment, with regard to development of antibiotic resistance, is lacking.
  • Continuously search for alternative management practices that reduce the need for antibiotics.

Control of antibiotic use in food animals should be in the control of veterinarians, within the context of a valid veterinarian-client-patient relationship, Apley says. Education on judicious use and antibiotic resistance should begin in veterinary schools and continue through post-graduate training. The veterinary community and producer organizations should not tolerate inappropriate activities that place public health at risk.

Apley adds that responsible involvement of veterinarians now can help them retain access to the tools they need while protecting their authority and role in the animal-health decision process.