Macrolide-resistant Campylobacter:: the meat of the matter

The use of macrolide antibiotics in food animals has the potential to select for macrolide-resistant strains of resident bacterial flora. This may include the animal pathogens that are the intended targets of macrolide antibiotic intervention and Campylobacter, common inhabitants of the intestinal tract of food animals that are zoonotic pathogens in man. Such Campylobacter strains are not only resistant to the macrolide antibiotics used in food animals, e. g. tylosin, tilmicosin and tulathromycin, but to the macrolide antibiotics used in human medicine, e. g. erythromycin, azithromycin and clarithromycin, as well. Retail meat is a possible source of Campylobacter and persons consuming the meat derived from macrolide-treated food animals could acquire infections due to macrolide-resistant strains of this organism. Erythromycin is sometimes used to treat human cases of campylobacteriosis and those infected with animal-derived macrolide-resistant Campylobacter may not respond to treatment. The actual risk to human health from the use of macrolide antibiotics in food animals has been difficult to determine because of a lack of information about the macrolide-resistant Campylobacter found on the farm and in the clinic. Recently, however, a plethora of new information has become available on this topic. This review discusses what is currently known about the selection of macrolide-resistant Campylobacter in food animals, the prevalence of macrolide-resistant Campylobacter on retail meat, the prevalence of animal-derived macrolide-resistant Campylobacter in the clinic and the human health consequences associated with macrolide-resistant Campylobacter infection. This work will emphasize the comprehensive body of data generated in Denmark and the US as part of government-sponsored research studies over the last 10 years. These scientific findings may allow informed decisions to be made in the future about how macrolide antibiotics should be used in food animals while still safeguarding human health.