Will new FDA rules curb antibiotic use in farm animals and the rise of superbugs?

The meat industry is facing mounting pressure to phase out antibiotic use. Here, we trace how a widespread use of those drugs can be bad for public health

New federal rules went into effect last week that ban the use of antibiotics to help livestock gain weight, a practice that leads to antibiotic-resistant bacteria that pose health threats to humans. Meat producers will also need a veterinary prescription to use these drugs for other purposes such as treating or preventing disease.

The new rules by the Food and Drug Administration (FDA) represent a broad attempt to limit antibiotic use in farm animals, not just banning a class of antibiotic for a type of livestock. Historically, antibiotics are given regularly to chicken, cattle, pigs and other animals not only to treat diseases but also to prevent them and to make the animals grow faster and bigger. But most of the antibiotics given to them are also used to treat humans and referred to as "medically important".