The fact that campylobacter bacteria is present on as much as 90% of raw chicken may not be news -- but nonetheless an outbreak of media reports about the bacteria's presence over the last two weeks has called public attention to the situation.
Poultry-industry sources told SN that so far they have seen no negative effects on sales as a result of this latest rash of media reports.
However, some scientists are publicly expressing concerns about the bacteria's presence on poultry. They are linking it to a rare disease, and are also saying that a new strain of campylobacter on poultry may be causing resistance to certain antibiotics in humans.
The poultry industry is maintaining that any risks related to campylobacter can be kept to a minimum, through proper cooking and handling practices.
The National Broiler Council, based in Washington, said its poultry-supplier members are not reporting decreases in chicken sales since campylobacter and chicken became the subject of TV news reports and articles in newspapers, including a front-page story in The New York Times late last month.
"We have known about campylobacter for 25 years. If you cook your chicken and keep your counters clean, it'll be no problem," said Bill Roenigk, senior vice president of the NBC.
"No one is alarmed to the extent that they are not buying chicken."
Estimates of reported annual cases of illness from campylobacter range from one million to eight million.
Estimated annual deaths nationally related to campylobacter infection range from 100 to 1,000. The more serious incidence of the disease usually results from further complications, and typically is more likely if the victim is elderly or immune-compromised.
Scientists interviewed by SN concurred with industry that the risk of campylobacter infection can be greatly reduced through proper handling and use of food-safety tools like irradiation, but several told SN they still were concerned about the bacteria's presence in the market.
"We know that campyplobacter is the most common bacterial pathogen. That's not news," said Craig Hedberg, an epidemiologist at the Minnesota State Department of Health, Minneapolis.
"What we have been seeing is an increase in the number of campylobacter [bacteria] that are resistant to fluoroquinolone," said Hedberg, referring to a class of antibiotics used on humans that was approved by the Food and Drug Administration for use on poultry in 1995.
The Minnesota State Department of Health's findings, indicating that 20% of campylobacter bacteria had fluoroquinolone-resistant strains, "suggest that the use of fluoroquinolone in chicken has led to development of these resistant organisms," said Hedberg.
He added that the increase in resistance varied from "very rare cases to a small percentage that is regularly identified." He also called the rise in fluoroquinolone-resistance since 1995 a concern, "because this is an important class of antibiotics and we are losing effectiveness of these because of use in animals."
Sean Altekruse, an epidemiologist at the Centers for Disease Control and Prevention, Atlanta, and liaison between the CDC and the FDA, said this pattern had been confirmed in Europe, where "there's a temporal association of the introduction of fluoroquinolone use in animals and [resistance in] humans.
"We now see the emergence of fluoroquinolone-resistance in Europe and there's reason to be concerned about it in the United States," he concluded.
In response to the Minnesota Department of Heath's findings about fluoroquinolone resistance, Kenneth May, a technical adviser to the NBC, said, "We don't treat anything like 20% of chickens with fluoroquinolone."
And the NBC's Roenigk concurred that the use of fluoroquinolone on poultry was very limited. "Less than one-tenth of 1% of chickens get treated with fluoroquinolone," he noted. "Fluoroquinolone is 25 times more expensive [than other antibiotics]."
He said he saw the option to use fluoroquinolone as simply another tool for the poultry industry.
Dean Cliver, a professor of food safety at the University of California, Davis, added that chickens aren't even directly treated for campylobacter. "Campylobacter, E. coli and salmonella don't sicken chickens. The ones that cause human sickness don't seem to bother the birds.
"Campylobacter is in chicken but it's not doing harm. As long as the chickens had only campylobacter there'd be no reason to give them antibiotics."
In addition, Cliver said, concern about campylobacter-induced fluoroquinolone resistance in humans was not an issue since "antibiotics are not recommended for treatment of campylobacter [in humans]."
Although Cliver said fluoroquinolone resistance could be growing, he said he was much more concerned with "people learning to handle raw chicken."
One of the methods of combating campylobacter proposed by Cliver was irradiation. "Not only will the irradiation process kill salmonella, it'll kill campylobacter just fine."
Christine Bruhn, a scientist at the Center for Consumer Research at the University of California, Davis, also agreed that irradiation was a useful tool to fight bacteria. "It's most effective because it destroys bacteria before you bring it home."
And potential problems posed by campylobacter aren't limited to poultry alone.
"Any warm-blooded animal could carry campylobacter," said the University of California's Cliver. And the NBC's Roenigk added that "since 1995 there's been a big debate because [fluoroquinolone use] is pending approval with cattle."
The Centers for Disease Control and Prevention meanwhile has reported a newly recognized link between campylobacteriosis and a rare disease, a claim that has been repeated in some news media reports.
The CDC estimates that one in every one thousand reported campylobacteriosis cases leads to Guillan-Barre syndrome -- a disease that can bring on temporary paralysis by triggering the immune system to attack the body's own nerves. The CDC reported that as many as 40% of GBS cases may be triggered by campylobacteriosis.