While the pharmaceuticals industry and some livestock farmers and veterinarians still contend that there isn’t yet definitive proof that the overuse of antibiotics is leading to the development and spread of drug-resistant bacteria , a new survey of American doctors found that there is nearly universal concern among doctors about this issue, and that many physicians have treated patients with drug-resistant infections in just the last year.

The report [PDF] from our colleagues at Consumers Union, along with groups like the National Resource Defense Council, U.S. Public Interest Research Group, and the National Physicians Alliance, looks at the results of a survey of 500 internal medicine and family practice physicians in the U.S.

Some 97% of doctors surveyed are at least fairly concerned about the growing problem of antibiotic resistant infections, with 59% of all respondents saying they were “extremely” concerned.

And when you look at how many of these physicians have treated patients with drug-resistant infections, it’s no surprise why there is such widespread concern.

According to the survey, 85% of these doctors have treated at least one patient in the last year with a bacterial infection that was resistant to multiple antibiotics.

Of those physicians, 35% have had one of these patients die or suffer significant complications as a result of these drug-resistant bugs.

Many doctors say they are taking steps to reduce the overuse of antibiotics in their practices. This includes refusing to prescribe antibiotics that are not medically necessary, even when patients ask for the drugs.

81% of physicians surveyed say they are now doing this, but that doesn’t necessarily mesh with recently released numbers from the Centers for Disease Control, which found that — as recently as 2010 — some 70% of U.S. doctors were still prescribing antibiotics for acute bronchitis, even though it’s been clearly demonstrated that antibiotics are not effective in treating that illness.

Another way in which doctors say they are trying to combat drug resistance is by prescribing the least broad spectrum antibiotic available (72%); and prescribing antibiotics for the shortest duration needed (68%).

In all, 80% of the physicians surveyed claimed that their practice, group, or hospital is actively working to minimize inappropriate prescribing of antibiotics.

But doctors’ offices and hospitals are only a slice of the antibiotics pie. Around 70% of medically important — and around 80% of all — antibiotics sold in the U.S. go into animal feed for non-medical growth-promotion of livestock and poultry. 93% of the doctors in the survey expressed concern about this practice.

The survey concludes with several policy recommendations for lawmakers, regulators, and private businesses.

This includes asking the FDA to strengthen its current stance on antibiotics in animal feed, by using its authority to restrict the use of these drugs only to cases of animal sickness or direct disease exposure, and to require proper veterinary oversight when antibiotics are used on farms.

Currently, the only tracking done of antibiotics in animal feed is the gross volume sold to farmers. The tracking doesn’t account for how much is actually being given to the animals or for what reason. The report asks the U.S. to adopt a robust tracking system to document the sale, use, and impacts of antibiotic use in livestock production.

It also includes a plea to private businesses like grocery stores, restaurants, and hospitals, asking them to adopt a policy to procure and sell only meat that is produced on farms that restrict the use of antibiotics except for animals that are actually sick, for a limited period of time–just as antibiotics are used in humans.