Nonculturability Might Underestimate the Occurrence of Campylobacter in Broiler Litter

We investigated the contribution of litter to the occurrence of Campylobacter on three broiler farms, which were known to have low (LO) and high (HI-A and HI-B) Campylobacter prevalence. For this purpose, we collected litter samples (n = 288) during and after two rearing cycles from each farm. We evaluated the occurrence of Campylobacter (using selective enrichment and quantitative real-time polymerase chain reaction [q-PCR] analysis) in the litter samples as well as the litter's pH and moisture content. Ceca from each flock (n = 144) were harvested at slaughter age and used to quantify Campylobacter colony-forming units (CFUs). Campylobacter was only retrieved from 7 litter samples that were collected from HI-A and HI-B during the growing period, but no Campylobacter was isolated from LO farms. The q-PCR analysis detected Campylobacter in pooled litter samples from all three farms. However, in litter collected during the same rotation, Campylobacter levels were significantly higher (p < 0.05) in HI-A and HI-B litter samples in comparison to those in LO. Cecal samples from HI-A and HI-B yielded relatively high numbers of Campylobacter CFUs, which were undetectable in LO samples. Litter's pH and moisture did not affect the overall occurrence of Campylobacter in litter and ceca on any of the farms. Our data suggest that Campylobacter was generally more abundant in litter that was collected from farms with highly colonized flocks. Therefore, better approaches for assessing the occurrence of Campylobacter in litter might be warranted in order to reduce the dissemination of these pathogens on and off poultry farms.