The researchers collected bacterial samples from 100 animals on farms that use antibiotics in their feed and 100 animals on farms that do not use antibiotics in their feed. They tested the bacterial samples for resistance against five commonly used antibiotics.

The results of the study showed that 80% of the animals raised on antibiotic-using farms had bacterial infections that were resistant to at least one antibiotic. In contrast, only 20% of animals on antibiotic-free farms had infections that were resistant to at least one antibiotic. The researchers concluded that the use of antibiotics in livestock feed is contributing to the prevalence of antibiotic-resistant bacteria in both animals and humans.

What are the potential consequences of the widespread use of antibiotics in livestock for human health?