In 2016, a new U.S. Food and Drug Administration policy will give veterinarians a key role in combating a surge in antibiotic-resistant "superbugs" that infect humans. For the first time, the agency will require veterinarians, not farmers, to decide whenever antibiotics used by people are given to animals.

Medical doctors issue antibiotics by prescription only. Yet farmers and food companies have been able to buy the same or similar drugs over the counter to add to feed and water. The drugs not only help prevent disease but enable livestock to grow faster on less feed.

The new directive is meant to guard against the overuse of the drugs in American meat production. But by enlisting the help of veterinarians, a Reuters examination found, the FDA will be empowering a profession that not only has allegiances to animals, farmers and public health, but also has pervasive and undisclosed financial ties to the makers of the drugs.