The high volume of antibiotics in food-producing animals contributes to the development of antimicrobial-resistant bacteria, particularly in settings of intensive animal production. In some countries, the total amount of antibiotics used in animals is 4 times larger than the amount used in humans. In many countries much of the antibiotics used in animals are for growth promotion and prevention of disease, not to treat sick animals.
These bacteria can be transmitted from animals to humans via direct contact between animals and humans, or through the food chain and the environment. Antimicrobial-resistant infections in humans can cause longer illnesses, increased frequency of hospitalization, and treatment failures that can result in death. Some types of bacteria that cause serious infections in humans have already developed resistance to most or all of the available treatments and we are running out of treatment options for some types of infection. WHO recommends an overall reduction in use of antibiotics in food-producing animals to help preserve their effectiveness for human medicine.