Diversity among Campylobacter spp., Using flaA Typing, through a Commercial Poultry Production and Processing Chain

Introduction: In Australia, Campylobacter is the leading cause of foodborne bacterial gastroenteritis, with chicken meat considered the primary vehicle of transmission. As chicken is the most consumed meat, this association is a major public health concern. Thus, understanding the ecology of Campylobacter in poultry production is critical to the development of effective management strategies.

Purpose: To determine the genetic diversity of Campylobacter spp. through primary production and processing in a commercial poultry operation, using flaA typing.

Methods: Campylobacter spp. (C. jejuni and C. coli) were isolated from a range of sampling sites through primary production (grow-out sheds) and subsequent processing of the same flocks. DNA was extracted and the flaA gene amplified using PCR. The amplicon from each isolate was digested with one of the restriction enzymes HinfI or DdeI. Fragments were resolved on 2% TBE agarose gels and patterns compared using computer software.

Results: Using HinfI or DdeI, 9 and 25 subtypes were produced, respectively, with 38 subtypes produced when the restriction patterns were used in combination. There was some correlation between HinfI and DdeI subtypes. There was evidence of sequential colonization and dominance of subtypes in primary production. Not only common types persisted through the production chain; a subtype found on only one farm was found on carcasses originating from other farms at the end of processing (post-chill). At the same time, some subtypes found commonly in primary production were not recovered post-chill.

Significance: The discriminatory power of flaA typing, based on restriction profiles generated using patterns from both HinfI and DdeI digestions, allows traceability of movement of strains of Campylobacter spp. through poultry primary production and processing.