Analysis of risk factors for Campylobacter species infection in broiler flocks.

We have sampled 146 German broiler flocks at slaughter from May 2004 to April 2005 to determine the prevalence of Campylobacter spp. and to investigate risk factors for the presence of Campylobacter spp. at flock level. Cecal samples were tested in accordance to ISO 10727, and potential risk factors were analyzed using farm- and flock-specific information obtained from questionnaires. Of the flocks tested, 44% were Campylobacter-positive, and most were infected with Campylobacter jejuni. Higher Campylobacter prevalence was found during the months of May to October (52%). Using farm- and flock-specific information obtained from questionnaires, we identified 3 risk factors for Campylobacter colonization. Campylobacter prevalence was significantly higher in flocks from free-range and organic farms, in flocks with a size up to 15,000 birds and with more than 25,000 birds, and in flocks using nipple drinkers with trays. We found no evidence of an effect of slaughter age, time interval between successive flocks, hygiene measures, number of broiler houses on a farm, partial slaughter, source of water supply, and number of farm employees on the Campylobacter infection rate.