Aims: To investigate the genetic diversity of Campylobacter in broilers and in the environment of broiler farms, to compare the genetic profiles and describe critical factors for transmission to broilers.
Methods and results: Flocks at three of four investigated farms became colonized with Campylobacter. The total proportion of Campylobacter-positive samples at different farms varied from 20% to 42%. The farm with the poorest biosecurity routines had broilers that became infected earliest, the highest proportion of positive samples and the highest genetic diversity among the broiler Campylobacter isolates. Campylobacter isolates within common amplified-fragment length polymorphism (AFLP) clusters (95-100%) were found to be present in outdoor environment and in broilers at adjacent farms before they were found in the broilers. A large presence of Campylobacter in the farm environment was demonstrated after the broilers were infected. A high genetic diversity was found among Campylobacter present in the outdoor environment, where certain Campylobacter clusters were found for periods of up to 6 weeks.
Conclusion: Confirmation by AFLP indicates adjacent poultry farms and outdoor environment as major sources of Campylobacter infection of broilers, this being the novel achievements.
Significance and impact of the study: The results provide more exact knowledge on transmission of Campylobacter at farm level, helpful for developing optimal preventive strategies.