Last Wednesday the USDA affirmed it supports the idea that there is a link between human health and the use of antibiotics in animals.
USDA chief veterinarian John Clifford said the department believes "the use of antimicrobials in animal agriculture does lead to some cases of antimicrobial resistance among humans and in animals themselves."
Clifford was giving testimony at a House committee hearing on the topic. Recently the Food and Drug Administration, which regulates antibiotics in animals and humans, proposed to end the use of many drugs as growth promoters in livestock. Only antibiotics such as ionophores that have no human use would be permitted to speed animals' growth. The FDA has set a schedule for phasing out the drugs' use or proposed specific restrictions.
Officials said the ban is needed to ensure that the drugs remain useful in human medicine.
Clifford was joined by officials from the FDA and the Centers for Disease Control and Prevention in telling a House Energy and Commerce subcommittee that there was evidence of a link between animal uses of antimicrobials and human health.
At an earlier hearing, government health experts said U.S. data on the linkage was lacking. But at the hearing, administration officials tried to make a closer connection. Studies of salmonella, for example, have shown that giving antibiotics to livestock causes bacteria in the animals to develop resistance and that resistant bacteria in food can be transmitted to people, said Ali Khan, the assistant surgeon general.
Agribusiness representatives and their allies on the committee said more research is needed.
"So far there's nothing that links use in animals to a buildup of resistance in humans," said Rep. John Shimkus, R-Ill.
A representative of the drug makers, Richard Carnevale of the Animal Health Institute, said there is "no unequivocal evidence" of a connection.
A committee member, Rep. Bruce Braley, D-Ia., said there were "very real production concerns" with restricting the drugs. He said "this is an issue that demands thoughtful careful consideration of all points of view."