Occurrence and Temporal Dynamics of Campylobacter spp. in Broiler Production Systems: Insights from Faecal and Air Monitoring

Campylobacter spp. are common commensals in broiler chickens and certain species are major causes of foodborne illness in humans. However, their on-farm dynamics and environmental dissemination remain poorly understood. This study investigated the occurrence and temporal dynamics of Campylobacter spp. in commercial broiler production systems by integrating faecal and airborne monitoring across three consecutive production cycles in two farms with contrasting productive historical performance. Faecal (n = 24) and air samples (n = 24) were analysed using culture-based methods, quantitative polymerase chain reaction (qPCR), and 16S rRNA gene amplicon sequencing, which were subsequently compared to assess concordance. In faecal samples, Campylobacter spp. colonisation generally occurred from mid-cycle onwards, with earlier and more consistent detection in the farm with suboptimal growth performance. In the optimal growth-performing farm, colonisation was not detected in the first cycle but emerged in subsequent cycles, coinciding with declining productive parameters, which include mortality, average weight at slaughter, Feed Conversion Ratio (FCR), and European Production Efficiency Factor (EPEF). Airborne Campylobacter DNA was intermittently detected by qPCR, in some cases preceding or occurring independently of faecal detection, whereas culture-based methods consistently failed to recover viable Campylobacter from air samples. Microbiome sequencing detected Campylobacter sporadically and at low relative abundances, yielding fewer positive detections across the monitored sampling timepoints than the targeted methods. Overall, qPCR proved to be the most sensitive approach across matrices, while faecal culture provided biologically meaningful data on viable loads. This study also documented temporal changes in Campylobacter detection patterns alongside productive performance indicators under commercial production conditions. These findings highlight the complementary value of faecal and airborne monitoring and underscore the importance of combining targeted molecular and culture-based approaches to characterise Campylobacter dynamics under commercial production conditions.