Parallel sequencing of porA reveals a complex pattern of Campylobacter genotypes that differs between broiler and broiler breeder chickens.

Chicken meat represents an important source of Campylobacter infections of humans world-wide. A better understanding of Campylobacter epidemiology in commercial chicken flocks will facilitate the development of more effective intervention strategies. We developed a gene-specific parallel sequencing approach that efficiently indicated genetic diversity in farm-derived samples and revealed Campylobacter genotypes that would not be detected using microbiological culture. Parallel sequencing of the porA nucleotide fragment identified a different pattern of diversity in broiler flocks compared with broiler-breeder flocks at both individual bird and flock levels. Amongst the flocks tested, broiler flocks and individual birds were dominated by one or two porA fragment types whereas co-dominance with up to six porA fragment types was evident in breeder birds. A high proportion (83.6-93.3%) of porA variants were shared between broiler and breeder flocks. The porA-based diversity profiling could be a useful addition to the repertoire of tools employed to attribute potential sources of contamination for broiler flocks, including the environment, wild animals or other chickens. This approach can be extended to include other loci within Campylobacter and developed for molecular epidemiology studies of other bacterial species.