Campylobacter bacteria in breeder flocks.

Nine Dutch breeder farms with a total of 43 separately housed flocks were examined for the presence of Campylobacter spp. and Salmonella spp. Penner serotyping of Campylobacter isolates was used to identify epidemiological factors contributing to the Campylobacter infection of these breeder flocks. Campylobacter was isolated from 29 of the 43 flocks (67%), and Salmonella was isolated from 12 flocks (28%). Two of the nine farms were both Campylobacter- and Salmonella-free at the time of sampling. Two other farms were Salmonella-free but Campylobacter-positive. A total of 330 Campylobacter isolates were serotyped, and 19 different Campylobacter serotypes were isolated in this study. Some similarities were observed in the patterns of serotype occurrence in houses of a given farm. Campylobacter colonization of breeder flocks indicates a potential role of vertical transmission via the egg to progeny. However, serotyping results did not support a vertical transmission route via the egg. Therefore, breeder flocks have to be recognized as another reservoir of Campylobacter, and it is more appropriate to consider them a potential risk factor in horizontal transmission routes.