The U.S. Food and Drug Administration (FDA) is expected to approve a powerful antibiotic for cattle despite warnings it would be dangerous for people, U.S. media reported on Monday.

The drug, called cefquinome, belongs to a class of highly potent antibiotics that are among medicine's last defenses against several serious human infections. No drug from that class has been approved in the United States for use in animals.

The fear is that using such drugs in animals can lead to the emergence of new drug-resistant "superbugs" which will be immune to similar drugs when used in people.

The overuse of antibiotics in both humans and animals has already helped such bacteria evolve, and infectious disease experts have been warning doctors to use them more judiciously.

Critics like Edward Belongia, an epidemiologist at the Wisconsin-based Marshfield Clinic Research Foundation, pointed to the approval of two powerful drugs in the 1990s for use in poultry, leading to a drug-resistant strain of campylobacter.

"The industry says that 'until you show us a direct link to human mortality from the use of these drugs in animals, we don't think you should preclude their use,'" Belongia said. "But do we really want to drive more resistance genes into the human population? It's easy to open the barn door, but it's hard to close the door once it's open."

InterVet Inc., a Delaware company, has applied to the FDA to market Cefquinome for treatment of a pneumonia-like disease, media reported.