COLUMBIA — To MU veterinarian John Middleton, the most significant impact of new government rules that govern the use of certain antibiotics on livestock will be increased accountability for farmers and veterinarians.
Under the new rules, livestock caretakers "have to think about what they're doing with the drugs," Middleton said, especially when the drugs are being used in ways not prescribed on the label. "It makes people pay attention."
An order issued by the Food and Drug Administration in early January limits certain uses of antibiotics known as cephalosporins in livestock. The order will go into effect April 5, following a 60-day comment period. The same antibiotics are used on people, and the tighter controls are designed to help guard against bacterial resistance in humans as well as livestock.
Use of the antibiotics for most disease prevention is now prohibited for the producers of cattle, swine, turkey and chicken. Producers are no longer allowed to use the antibiotics in ways not stated on the label except when veterinarians prescribe specific uses.
Doctors write more than 50 million prescriptions for cephalosporin antibiotics each year, according to the FDA. The antibiotics are commonly used to treat pneumonia, strep throat and skin and urinary infections in humans. The antibiotics are also prescribed by pediatricians to treat infections in children.
The antibiotic ceftiofur, a cephalosporin, is a "first-line" antibiotic for doctors treating salmonella infections, according to the FDA. In 2009, the U.S. Department of Agriculture reported a 14.5 percent increase in salmonella resistance to ceftiofur in cattle as well as a 4.2 percent increase for swine, 12.2 percent increase for chicken and 8.7 percent increase in turkeys.
Surveillance programs in the U.S. and Canada report increasing resistant bacterias of animal origin to cephalosporin treatment in humans, according to the FDA order.
Middleton engages in research at the veterinary school in the area of bovine mastitis treatment and prevention. Mastitis is a common infection among cattle that inflames the udder and is commonly treated by a cephalosporin antibiotic, such as cephapirin.
"We've actually seen an increase in the susceptibility of microbes to commonly used antibiotics, not resistance, in mastitis treatment," Middleton said.
Cephapirin is not regulated by the new order because it is not used to treat humans.
"When you expose a population of microbes to antibiotics in a population of animals, there is always a chance for the resistant strain to become prevalent," Middleton said.
Middleton pointed to the misuse of antibiotics in humans as a contributing factor to the development of resistant bacteria.
"What we really need to focus on is not whether antibacterial use causes resistance — because it does," Middleton said. "We need to focus on what type of use causes more resistance than another."
John Denbigh, farm manager of the University Dairy Farm, sees the new rule as "more of an awareness-type situation."
"Maybe don't grab it as the first thing you think about. It really isn't going to alter the use of it, as long as you follow label instructions,”Denbigh said.
Jeff Windett, executive vice president of the Missouri Cattleman's Association, said he doesn't believe the new rules will have much of an impact on farmers. He sees a "minimal effect, if any, in beef production."
Windett said, however, that his organization was "concerned this could lead to other bans." Windett is most concerned about the "FDA's over-reach in the regulation of antibiotics in livestock.
"Discussions about regulating farm-use antibiotics is an important tool for our producers to be aware of," Windett said. "Research has shown that there is virtually no impact of livestock antibiotic use in human resistance."
"It's easy to target livestock production. It's easy to target antibiotic use in human medicine. The bottom line is, it's not that simple," Middleton said. "We all need to focus on using antibiotics responsibly."
Mark Mahnken of Missouri Legacy Beef, which chose to go antibiotic free in response to consumer interest, supports the new FDA rules.
"In general, my past experience has been with extra-label use, which hasn't been very successful anyway, and it is not very efficient," he said. "These type of actions will probably, in the long term, be justified and good for the consumer."
The FDA order cites numerous studies relating to the resistance of microbes against antibiotics, an issue that's been in play since the 1970s.
Just before Christmas, the FDA gave notice that it would remove a 34-year-old policy that proposed to regulate uses of penicillin and tetracyclines in food-producing animals. The FDA states "other ongoing regulatory strategies" as to why this policy was retracted, and the recent order is one of these strategies.