Farmers and the food industry should stop using antibiotics to promote growth and prevent disease in healthy animals, the World Health Organisation (WHO) has warned. On November 7, the global health body published new guidelines with the aim of preserving the effectiveness of antibiotics that are important for human medicine. According to WHO, the over-use and misuse of antibiotics in animals that are otherwise healthy is contributing to the rising threat of antibiotic resistance. It is not the first warning of that kind: As long ago as 1997, WHO warned against the sub-therapeutic use of antibiotics in livestock production, as the development of resistant strains of bacteria made diseases untreatable with antibiotics. Some types of bacteria that cause serious infections in humans have already developed resistance to most or all of the available treatments, and the problem is that there are very few other promising options in the research pipeline. “Scientific evidence demonstrates that overuse of antibiotics in animals can contribute to the emergence of antibiotic resistance,” says Dr Kazuaki Miyagishima, Director of the Department of Food Safety and Zoonoses at WHO. “The volume of antibiotics used in animals is continuing to increase worldwide, driven by a growing demand for foods of animal origin, often produced through intensive animal husbandry.” In some countries, approximately 80% of total consumption of medically important antibiotics is in the animal sector, largely for growth promotion in healthy animals.

The WHO guidelines recommend an overall reduction in the use of all classes of medically important antibiotics in food-producing animals. The health body points to a systematic review published in the journal “The Lancet Planetary Health” which found that interventions that restrict antibiotic use in food-producing animals reduced antibiotic-resistant bacteria in these animals by up to 39%. Healthy animals should only receive antibiotics to prevent disease if it has been diagnosed in other animals in the same flock, herd, or fish population. Antibiotics used in animals should be selected from those WHO has listed as being “least important” to human health, and not from those classified as “highest priority critically important”. In addition, the health experts recommend a complete restriction of the use of all classes of medically important antimicrobials in food-producing animals for growth promotion. WHO highlights that many countries have already taken action to reduce the use of antibiotics in food-producing animals. For example, since 2006, the European Union has banned the use of antibiotics for growth promotion. However, the guidelines do not explicitly address the problems of a farming system that depends on antibiotics to keep animals healthy. It just calls for the implementation of alternative options to using antibiotics for disease prevention in animals, including improved hygiene, better use of vaccination, and changes in animal housing and husbandry practices. (ab)