Longitudinal Transmission of Campylobacter jejuni Subtypes throughout the Broiler Chicken Production Continuum

• Author / Creator

  Ramezani, Nahal

• The broiler chicken production continuum (including three commercial broiler farms, abattoir and retail poultry stream) was sampled longitudinally over a 542-day period in Southwestern Alberta (SWA) as a model agroecosystem. Furthermore, fecal samples collected from beef cattle in a confined feeding operation adjacent to one of the broiler farms, and stools from diarrheic human beings in SWA were collected during the sampling period. Campylobacter jejuni isolates were recovered from chickens using two methods (i.e. direct plating and enrichment/membrane filtration). Presumptive Campylobacter isolates from chickens, beef cattle, and diarrheic human beings were identified by taxon-specific polymerase chain reaction, and C. jejuni isolates were genotyped using a high resolution comparative genome fingerprinting method. The results showed that C. jejuni outbreaks were uncommon events in broiler farms. When infections occurred, they happened late in the production cycle, and typically in the spring and summer. When a flock was exposed to C. jejuni, the entire flock rapidly become colonized by a limited number of subtypes. Subtype diversity increased from farm to abattoir and retail. In many instances, birds deemed free of C. jejuni in the farms became contaminated during transport to and within the abattoir. Only a subset of C. jejuni subtypes isolated from broilers and poultry meat were deemed to represent a significant risk to human health. A high prevalence of beef cattle adjacent to one of the poultry farm sampled frequently shed diverse C. jejuni subtypes in their feces, including subtypes that infect people. Furthermore, C. jejuni subtypes responsible for outbreaks in chickens were observed in feces from steers in the feedlot, implicating beef cattle as an important reservoir of C. jejuni infecting broiler chickens. In conclusion, study findings showed that a relatively small number of birds are able to contaminate the abattoir with diverse C. jejuni subtypes, and clean birds are infested with these subtypes within the abattoir, which are subsequently transferred to retail meat. Importantly, only a subset of C. jejuni strains pose a risk to human health, and efforts to reduce the burden of foodborne C. jejuni on human beings should focus on mitigation of high risk subtypes within the abattoir.

• Subjects / Keywords

  • Campylobacter jejuni
  • Comparitive Genome Fingerprinting
  • Broiler Chicken Production Continuum
  • Southwestern Alberta

• Graduation date

  Spring 2019

• Type of Item

  Thesis

• Degree

  Master of Science

• DOI

  https://doi.org/10.7939/r3-0cxw-sd02

• License

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