Danger to human health | Antibiotic resistance could nullify effectiveness of human medicines, say some researchers
ATLANTA/CHICAGO (Reuters) — Major U.S. poultry firms are administering antibiotics to their flocks far more pervasively than regulators realize, posing a potential risk to human health.
Internal records examined by Reu-ters reveal that some of the nation’s largest poultry producers routinely feed chickens an array of antibiotics, not just when sickness strikes but as a standard practice over most of the birds’ lives.
In every instance of antibiotic use identified by Reuters, the doses were at the low levels that scientists say are especially conducive to the growth of bacteria that gain resistance to conventional medicines used to treat people.
Read Also
Agriculture ministers agree to AgriStability changes
federal government proposed several months ago to increase the compensation rate from 80 to 90 per cent and double the maximum payment from $3 million to $6 million
Some of the antibiotics belong to categories considered medically important to humans.
The internal documents contain details on how five major companies — Tyson Foods, Pilgrim’s Pride, Perdue Farms, George’s and Koch Foods — medicate some of their flocks.
The documented evidence of routine use of antibiotics for long durations was “astonishing,” said Donald Kennedy, a former U.S. Food and Drug Administration commissioner.
Kennedy, president emeritus of Stanford University, said such widespread use of the drugs for extended periods can create a “systematic source of antibiotic resistance” in bacteria, the risks of which are not fully understood.
“This could be an even larger piece of the antibiotic-resistance problem than I had thought,” Kennedy said.
Reuters reviewed more than 320 documents generated by six major U.S. poultry companies during the past two years. Called “feed tickets,” the documents are issued to chicken producers by the mills that make feed to poultry companies’ specifications.
They list the names and grams per ton of each “active drug ingredient” in a batch of feed. They disclose the FDA-approved purpose of each medication. As well, they specify which stage in a chicken’s roughly six-week life the feed is meant for.
The feed tickets that were examined represent a fraction of the tens of thousands issued annually to poultry farms run by or for major producers in the U.S. The confidential information they contain nonetheless extends well beyond what the U.S. government knows.
Veterinary use of antibiotics is legal and has been rising for decades. However, U.S. regulators don’t monitor how the drugs are administered on the farm: in what doses, for what purposes or for how long.
The tickets indicate that two of the poultry producers — George’s and Koch Foods — have administered drugs belonging to the same classes of antibiotics that are used to treat infections in humans.
The practice is legal, but many medical scientists deem it particularly dangerous because it runs the risk of promoting antibiotic-resistant bacteria that can defeat the life-saving human antibiotics.
Another major producer, Foster Poultry Farms, acknowledged that it too has used drugs that are in the same classes as antibiotics considered medically important to humans by the FDA.
About 10 percent of the feed tickets reviewed by Reuters list antibiotics belonging to medically important drug classes.
However, in recent presentations, scientists with the U.S. Centers for Disease Control and Prevention said the use of any type of antibiotic, not just medically important ones, contributes to resistance.
Scientists and public health experts said frequent, sub-therapeutic use of antibiotics in low doses intensifies that effect. The risk is that any resulting antibiotic-resistant bacteria might also develop cross-resistance to medically important antibiotics.
According to the feed tickets that were reviewed, low doses of antibiotics were part of the standard diet for some flocks at five companies: Tyson, Pilgrim’s, Perdue, George’s and Koch.
“These are not targeted uses aimed at specific bugs for defined duration,” said Keeve Nachman, director of the food production and public health program at Johns Hopkins University’s Bloomberg School of Public Health.
“They’re multiple, repeat shotgun blasts that will certainly kill off weaker bugs and promote the stronger, more resistant ones
This month, Perdue Farms an-nounced that it had stopped applying the antibiotic gentamicin to eggs in chicken hatcheries. Gentamicin is a member of an antibiotic class that the FDA considers “highly important.”
The company said it wants “to move away from conventional antibiotic use” because of “growing consumer concern and our own questions about the practice.”
However, the move won’t change what Perdue feeds its chickens. Some of its feed has contained low levels of one antibiotic, feed tickets show. Perdue said it uses only antibiotics that aren’t considered medically important by the FDA. At some farms, it uses no antibiotics at all.
“We recognized that the public was concerned about the potential impact of the use of these drugs on their ability to effectively treat humans,” Bruce Stewart-Brown, Perdue’s senior vice-president of food safety and quality, said when the hatchery policy was announced.
The poultry industry’s lobby takes issue with the concerns of government and academic scientists, saying there is little evidence that bacteria that do become resistant also infect people.
“Several scientific, peer reviewed risk assessments demonstrate that resistance emerging in animals and transferring to humans does not happen in measurable amounts, if at all,” said Tom Super, spokesperson for the National Chicken Council.
He said using antibiotics to prevent diseases in flocks “is good, prudent veterinary medicine. Prevention of the disease prevents unnecessary suffering and prevents the overuse of potentially medically important antibiotics in treatment of sick birds.”
