Playing chicken with antibiotics

Antibiotics injected into chicken eggs is making Canadians resistant to meds

Playing chicken with antibioticsDisturbing data from the Public Health Agency of Canada reveals that antibiotics such as cephalosporin used in chicken hatcheries across the country is causing human resistance to the medicines, according to a startling report in the Canadian Medical Association Journal today.

Surveillance information from the Canadian Integrated Program for Antimicrobial Resistance (CIPARS), which is funded by the public health agency, “strongly indicates that cephalosporin resistance in humans is moving in lockstep with use of the drug in poultry production,” the CMAJ explains.

In 2005, chicken bought at Ontario and Quebec supermarkets had high levels of cephalosporin-resistant bacteria. Meanwhile, widespread use of ceftiofur, which is a type of cephalosporin, was found at Quebec chicken hatcheries. When farmers stopped using ceftiofur briefly due to the evidence drawn by CIPARS, there was a massive drop in cephalosporin resistance in salmonella samples taken from humans and retail poultry, says the CMAJ.

More than a couple of years have passed since then, and researchers are once again seeing an increase in resistance. The latest data for Ontario, released in March, shows that there was a spike in ceftiofur resistance in humans and chickens. Between 2007 and 2008 there was a jump in bacteria resistance in retail
chicken in Quebec, Saskatchewan and British Columbia—from 29 per cent to 46 per cent in the latter province, which prompted a B.C. disease specialist to call the rise “alarming.”

Cephalosporin is not approved for use in chickens or eggs, but it is often “robotically injected” into eggs at chicken hatcheries as a preventative measure to stave off infections, reports the CMAJ. This occurs on an off- or extra-label basis, which means that the drug is being used for unapproved reasons. Health Canada has issued a safety warning label about off-label use of cephalosporin, but critics say that is not enough and want tighter restrictions or a ban on the sale of these antibiotics for food animal production.

Such a move wouldn’t come easily. Last July, the U.S. Food and Drug Administration tried to ban off-label use of cephalosporin after it analyzed CIPARS data. The food animal industry pushed back, and so the FDA recanted. Some suspect a similar sequence of events would occur here. The CMAJ even goes as far as to suggests that “in Canada, it appears that industry concerns trump precautionary principles.”

Critics argue that the CIPARS data doesn’t provide sufficient evidence of a link between ceftiofur and rising human resistance. They question the validity of the data because CIPARS can’t access information about antibiotic use in chickens, which is collected by the Canadian Food Inspection Agency, because it is confidential. For its part, the Chicken Farmers of Canada group says it’s working with CIPARS to promote better surveillance of antibiotic use in chickens.

As astounding as the latest data is, concerns about cephalosporin farm use are not new. The CMAJ reports that the European Union has long condemned off-label use of antibiotics in Canadian food animal production. In fact, at one point Ottawa promised to improve its controls, and even began a national study of antibiotic food animal use—but it was eventually dropped. Last December the Ontario Auditor General raised the issue again, and even a director of procurement at Maple Leaf Foods has expressed worries.

Perhaps this next round of troubling data will prompt action. One Danish scientist told CMAJ that there’s good reason to take the CIPARS information seriously. “Anyone still opposing a link between antibiotic use in food animal production and direct human health impact does so for other reasons than science.”

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