Antibiotic-resistant super bacteria: It sounds like the makings of a science fiction plot. But it’s a real concern for some, and it’s the reason the livestock and drug industries are united in a fight on Capitol Hill against efforts to regulate the use of antibiotics in animal feed.

Cattle, hog and poultry producers use higher doses of antibiotics to treat animals when they are sick and when they might be under stress — perhaps from being transported or being weaned — because stress can make them susceptible to infections. Low doses of the drugs are used to accelerate animals’ weight gains for market. For an undetermined reason, animals seem to able to make more efficient use of nutrients with the antibiotics in their systems.

The issue of when and how often antibiotics should be used — in people as well as in animals — has risen in prominence in the health care community. The concern is that widespread use of antibiotics to treat human illnesses has helped create pathogens immune to those drugs. Going a step further, health officials and some lawmakers worry that eating beef, pork or poultry that comes from animals that were fed antibiotics will add to that potential problem.

The livestock industry, along with farm state lawmakers and pharmaceutical companies, have fought legislation for several Congresses, arguing there is no definitive evidence that antibiotic use in food animals has contributed to the creation of resistant disease-causing bacteria.

A House bill, sponsored by New York Democrat Louise M. Slaughter, would require the Food and Drug Administration to deny approval for new drugs for food animals if they contain antibiotics or other drugs used to treat humans and if a drug company cannot prove that it is unlikely to lead to resistance in pathogens. The bill (HR 965) has 92 co-sponsors but has not been given a hearing or a committee or floor vote. Sen. Dianne Feinstein, D-Calif., has a companion bill (S 1211) with seven co-sponsors.

“When we go to the grocery store to pick up dinner, we should be able to buy our food without the worry that eating it will expose our family to potentially deadly bacteria that will no longer respond to our medical treatments,” Slaughter said in a 2011 floor speech. “Unless we act now, we will unwittingly be permitting animals to serve as incubators for resistant bacteria.”

Slaughter, who has been fighting for such legislation for years, is getting support from the Centers for Disease Control and Prevention. Designating this week as “Get Smart on Antibiotics Week,” the CDC issued a warning that once a drug is ineffective, physicians have a limited number of alternatives they can use.

In the 1980s, drug companies put 29 new antibiotics on the market. That number has fallen to nine in the past decade, according to a study by the CDC and Pew Charitable Trusts. The agency and the foundation say antibiotic resistance accounts for 60,000 deaths a year and $26 billion in additional health care costs.

The CDC has formed a coalition with 26 groups — including The Infectious Disease Society of America, The Society for Healthcare Epidemiology of America and The Society of Infectious Disease Pharmacists — with the mandate to protect the effectiveness of antibiotics and slow the development of antibiotic resistance.

As part of its campaign, the coalition released a plan that includes a focus on agriculture’s use of antibiotics. While there’s no reference to mandatory regulations, the group did issue a call “to reinforce the judicious use of antibiotics in agriculture.”

Antibiotic use on animals is part of the equation, Arjun Srinivasan of the CDC said. Antibiotic levels in food animals are often below the amounts generally used in treating human illness, he said, and those who see a link between drug use in animals and resistant microbes say the sub-therapeutic levels allow bacteria to adapt and to make subsequent generations nearly immune to certain antibiotics. “We must work on both sides of this issue,” he said.

An estimated 80 percent of all antibiotics produced in the United States are given to animals, most of them grown for food, the CDC and FDA, among others, say.

Producers say the science linking antibiotics to resistance in humans is inconclusive. They argue it is not enough to support what they see as sweeping and costly restrictions on drugs that help them stay in business.

“Through multiple industry-led initiatives … ranchers work with veterinarians to select and use antibiotics carefully and when needed,” J.D. Alexander, president of the National Cattlemen’s Beef Association, said in a statement Thursday.

In the meantime, supporters do not expect to see much movement on this issue until the next Congress. Rep. Henry A. Waxman, ranking Democrat on the House Energy and Commerce Committee, plans to file legislation this month that would require drug companies to detail agricultural use of antibiotics, including the type of animals that receive the drugs and the reason the drugs were administered. But he does not expect anything to happen with it until the 113th Congress. The plan at this point is probably to try to include it in the Animal Drug User Fee Act, which will be up for reauthorization in 2013.