Comparison of genotypes and serotypes of Campylobacter jejuni isolated from Danish wild mammals and birds and from broiler flocks and humans

The incidence of human infection with Campylobacter jejuni is increasing in most developed countries and the reason for this is largely unknown, Altho ugh poultry meat is considered to be a major source, it is evident that oth er reservoirs exist, possibly common to humans and poultry, Environmental s ources are believed to be important reservoirs of Campylobacter infection i n broiler chicken flocks. We investigated the potential importance of wildl ife as a source of infection in commercial poultry flocks and in humans by comparing the serotype distributions, fla types, and macrorestriction profi les (MRPs) of C. jejuni isolates from different sources. The serotype distr ibution in wildlife was significantly different from the known distribution s in broilers and humans. Considerable sero- and genotype diversity was fou nd within the wildlife collection, although two major groups of isolates wi thin serotype O:12 and the O:4 complex were found. Common clonal lines amon g wildlife, chicken, and/or human isolates were identified within serotype O:12 and the O:4 complex. However, MRPs of O:12 and O:38 strains isolated f rom wildlife and other sources indicated that some clonal lines propagated in a wide selection of animal species but were not detected in humans or br oilers in this study. The applied typing methods successfully identified di fferent clonal groups within a strain collection showing large genomic dive rsity. However, the relatively low number of wildlife strains with an infer red clonal relationship to human and chicken strains suggests that the impo rtance of wildlife as a reservoir of infection is limited.