Key facts discount comments made on antibiotics segments aired last month.

There were so many blatant discrepancies in the CBS Evening News two-part report on antibiotics last month that Scott Hurd, DVM, associate professor at Iowa State University, decided to respond directly to the false claims.

Below are highlights of CBS anchor Katie Couric's statements and Hurd's clarifications.

CBS: A University of Iowa study last year found a new strain of methicillin-resistant staphylococcus aureus (MRSA) in 70% of hogs and 64% of workers on farms in Iowa and Illinois where antibiotics are used routinely. On antibiotic-free farms, no MRSA was found.

Hurd: This was a very small pilot study of 300 pigs in which only six farms used antibiotic-free production methods. In other countries, some organic farms are 100% positive for MRSA. In the Iowa study, some conventional hog farms were totally free of MRSA. A second University of Iowa study, unreported by CBS, found conventional farms with MRSA rates in 23% of pigs and 58% of workers.

CBS: Health officials are concerned if workers who handle animals are getting sick — what about the rest of us? Drug-resistant infections have skyrocketed over the past two decades, killing an estimated 70,000 Americans last year alone.

Hurd: The drug-resistant infections referred to here have little to no relationship to any antibiotic use in animal agriculture. Drug-resistant infections that are often lethal are often associated with hospital-acquired infections and the antibiotics used in those facilities.

The Food and Drug Administration also says drug resistance in food-borne illness is stable to declining.

CBS: Antibiotic resistance is an emerging health crisis that scientists say is caused not only by the overuse of antibiotics in humans, but in livestock as well. Antibiotics are fed to healthy animals to promote growth and prevent disease.

Hurd: Strategic use of antibiotics in animal agriculture prevents disease and produces safer food, of which a side benefit is faster growth. Antibiotics have been used in humans for more than 60 years and in livestock for about 50 years. The fact that an epidemic of resistance related to antibiotic use in agriculture has not occurred by now shows that it is not a major risk to human health.

CBS: One chief medical officer fears someday there will be an organism that's resistant to everything, and says concerns about antibiotics being added to animal feeds may be contributing to MRSA and other antibiotic resistance.

Hurd: While the types of antibiotics used in animal feeds do not contribute to the development of MRSA, the concern over the development of antibiotic resistance is why veterinarians and farmers have spent more than 20 years improving antibiotic use.

CBS: Evidence of MRSA has been found in the nation's meat supply. But it's unclear how widespread it may be, because only a small fraction is tested for MRSA.

Hurd: MRSA is not a food-borne illness, so testing meat for it is not necessary. The federal Centers for Disease Control and the European Food Safety Authority agree that the risk of MRSA from handling or eating meat is very low.

CBS: If bacteria become resistant to antibiotics, it can spread in the food supply and in water runoff from a farm.

Hurd: There is no evidence to support that these routes contribute to human health concerns of antibiotic resistance. Food-borne illness rates are declining. Environmental spread of these pathogens is largely theoretical.

CBS: Growing animals bigger, faster is a sales point pushed by pharmaceutical firms. Antibiotics are also needed to keep disease from spreading like wildfire in crowded confinement pens.

Hurd: Antibiotics are only one tool used to maintain animal health in farms of all sizes and structures. Antibiotics help animals grow healthier, improve animal well-being, and help provide safe food.

CBS: The bottom line on antibiotic use is no one is really monitoring it.

Hurd: The Food and Drug Administration regulates antibiotic use in both humans and animals.

CBS: Antibiotics in Denmark are used sparingly and only when animals are sick.

Hurd: That is true. The result has been an increase in diarrhea in pigs and a 25% increase in pig deaths. The number of farms in Denmark has declined from 25,000 in 1995 to less than 10,000 in 2005, many exiting due to this ban.

Ironically, once a pig becomes visibly sick, the Danish government allows farmers to use antibiotics similar to those used in humans.

CBS: Since the antibiotic ban, the Danish pork industry has grown by 43%, making it one of the top pork exporters.

Hurd: The net growth of the Danish pork industry has been about 5%, not 43%, while use of antimicrobials to treat sick animals has grown 110%.

CBS: An experiment to stop widespread use of antibiotics was launched 12 years ago, when European studies showed a link between animals daily consuming feed with antibiotics and people developing antibiotic-resistant infections from handling or eating that meat.

Hurd: No studies ever showed such a linkage.

CBS: Without growth-promoting antibiotics, it only costs $5 more for every 100 pounds of U.S. pork produced.

Hurd: An Iowa State University analysis shows that a U.S. ban on antibiotics would add $6/hog to the cost of production. The total cost of a ban over 10 years could exceed $1.1 billion and boost consumer pork prices by 2%.

The focus of the ban should be on public health, not the cost of production. The World Health Organization has found no indication that Danish health has improved.

CBS: A Danish study has confirmed that the antibiotic ban has drastically reduced antibiotic-resistant bacteria in animals and food.

Hurd: The only resistance that decreased was in enterococcus, not a food-borne pathogen.

Denmark's ban and switch to treatment drugs for animals similar to those used in humans may create more risk than before. Resistance in human food-borne pathogens, such as salmonella and campylobacter, hasn't decreased at all.

To view the full report, visit http://vetmed.iastate.edu.