Risk assessment for antibiotic resistance: use of macrolides in Danish pig production

Abstract

What is the risk that use of antibiotics in farm animals will result in treatment failure in humans? Different approaches can address this. One approach is to make a risk profile and another to conduct a risk assessment. Use of macrolides in Danish pigs will be used as an example that demonstrates how the conclusion depends on the approach. A risk profile mcludes a description of the hazard and a qualitative assessment of the risk, similar to hazard identification. Accordingly, macrolide-resistant Campylobacter might develop as a result of usage of macrolides in p1g production. This is of concern for human health . because it might reduce the effect of erythromycin, a macrolide used in chi ldren for treatment of Campylobacter infections. A full risk assessment contains an assessment of release, exposure, and consequences related to the unwanted outcome. Release deals with the probability that Campylobacterwill be present m the gut, and how often the isolates found are resistant to macrolides. Exposure relates to the probability of a person being exposed to macrolide-resistant Campylobacter, and here the prevalence in pork - and not live pigs - is of interest. The consequences deal with the outcome of exposure· likelihood of disease/adverse effects. Campylobacter is commonly occurring in the pig gut, and so is macrolide­ resistance in Campylobacter in pigs. However, the prevalence of Campy/obacter in Dan1sh pork at re tai l is negligible because of use of blast-chilling after slaughter. Human campylobactenos1s IS us uall y self-limiting . One study describes adverse effects related to infection with macrolide­ resistant Campylobacter- but the effect was severely confounded with age and co-morbidity, and no children got adversely affected. So according to the risk assessment, the risk associated with veterinary use of macrolldes in Danish pigs for the health of humans seemed low. Th1s IS contrary to the resu lt obtained by the risk profile.