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Published at www.cmaj.ca on Jun. 17.
Alarming new data from the Public Health Agency of Canada suggests that widespread offlabel use of cephalosporin antibiotics in poultry hatcheries is triggering human resistance to the class of antibiotics.
Experts say the data warrants restrictions on off-label (use of drugs for unapproved clinical indications, also known as extra-label) farm use of cephalosporins in the interest of public health.
Health Canada's response to date has been the introduction of nonbinding labels warning against off-label cephalosporin use in agriculture - a measure that critics say has had little effect on usage levels.
Although the department promised the European Commission almost a decade ago that it would tighten controls on off-label use of drugs in agriculture, and acknowledges that it could ban the sale of cephalosporins for use in all or some food animals, it contends that jurisdiction over farm use of the antibiotics falls within the purview of the provinces. Health Canada, a spokesman says, "does not have authority over extra-label drug use."
Critics counter that the government is simply dodging action on a growing public health problem and should obligate meat and poultry producers to curb antibiotic use and modify practices that stress animal health.
Much of the debate surrounds surveillance data from the Canadian Integrated Program for Antimicrobial Resistance (CIPARS), which strongly indicates that cephalosporin resistance in humans is moving in lockstep with use of the drug in poultry production.
Financed by a $3-million annual contribution from the Public Health Agency of Canada, CIPARS has been tracking antimicrobial-resistant bacteria in food and on farms since 2002. In 2005, it reported startling levels of cephalosporinresistant bacteria in chicken samples purchased in grocery stores in Quebec and Ontario and in samples taken from humans (www.phac-aspc.gc.ca/ciparspicra/2005-eng.php). At the same time, a study revealed near-universal use of ceftiofur, a cephalosporin- type antibiotic, in Quebec chicken hatcheries.
The resistance levels in Quebec were so high that hatcheries voluntarily agreed to temporarily suspend ceftiofur use. CIPARS director Rebecca Irwin says the temporary ban led to a rapid reduction in cephalosporin resistance in salmonella samples taken from humans as well as from retail chicken products.
But more than 2 years after the voluntary ban was lifted, the latest data on poultry products purchased in the...