Antimicrobial Resistant Campylobacter species in the Food Chain: Understanding the Human Risk of Infection

  • Author / Creator
    Neustaedter, Christine
  • Background: Campylobacter spp., commonly detected in poultry, are the third most common cause of foodborne illness in Canada. Campylobacter while self-limiting and typically only requiring supportive care treatment, can be resistant to antimicrobials important to human health. To better understand the dissemination of antimicrobial resistant Campylobacter, the overall objective of this thesis was to investigate the human exposure to, and risk from, antimicrobial resistant Campylobacter in Canada. In addition to investigating transmission pathways in general, because of the contribution of chicken meat to Campylobacter spread, this thesis also investigated the potential exposure from broiler chickens.

    Methods: A scoping review was used, following PRISMA guidelines and the Joanna Briggs Institute framework, to determine factors potentially associated with human infection with Campylobacter spp. that are resistant to fluoroquinolones, macrolides, or tetracyclines. An integrated assessment model component was developed to evaluate the probability of human exposure to antimicrobial resistant Campylobacter spp. from broiler chicken in Canada, specifically resistance to fluoroquinolones, tetracyclines, or macrolides, and identify knowledge and data gaps.

    Results: The scoping review identified 8,527 de-duplicated articles and 27 articles were included after screening. Factors were broadly categorized into seven categories: animal contact, prior antimicrobial use, participant characteristics, food and food preparation, travel, underlying health conditions, and water. Articles exploring factors related to travel (n=17) and participant characteristics (n=14) were most common. The factors and regions studied, the types of investigations, and the knowledge they contributed were broad and diverse. The populations included, data sources utilized, and analyses employed varied greatly. Travel was an important risk factor, and infections were commonly associated with gastrointestinal Campylobacter jejuni and were often evaluated using only a univariable analysis. Most of the studies were conducted in a small sample of high-income, westernized countries.
    The integrated assessment model literature review identified 7,344 de-duplicated articles of which 15 articles were included in the qualitative synthesis after screening. Identified factors were allocated into the model at three stages of production: farm, abattoir, and retail. Factors included management practices, antimicrobial use on farm, chilling type at processing, and packaging type. Two scenarios were compared to a reference scenario to investigate:

    1. How the Canadian context influenced human exposure to antimicrobial resistant Campylobacter.
    2. How fluoro(quinolone) use in broiler chickens influenced human exposure to antimicrobial resistant Campylobacter.

    Conclusions: This thesis contributed the first scoping review of potential factors associated with human infections with antimicrobial resistant Campylobacter. The heterogeneity of the results and articles provided a broad overview of the available factors while also illuminating areas for potential future research. These future research areas include studies examining time at risk and AMR, the effect of comorbidities that require antimicrobial use, and the recent effects of antimicrobial stewardship policies.
    This thesis also represents the first integrated assessment model that brings together the body of literature to estimate human risk of exposure to antimicrobial resistant Campylobacter from broiler chicken in Canada. This model framework can now be used for future understanding of the risk of exposure of Canadians from the broiler production chain. The model also provided initial insights into factors that may influence the levels of antimicrobial resistant Campylobacter in the broiler food chain while identifying substantial gaps in data and knowledge. The median estimated number of Canadians potentially exposed (NCPE) values ranged from 101.71 to 2,052.65 standardized per 100,000 and the maximum values ranged from 14.041.95 to 19,066.81 standardized per 100,000. One key result from the fluoroquinolone resistance model suggests that there is persistent fluoroquinolone resistant Campylobacter spp. in Canada in broiler chickens. Two important assumptions of interest were that modeled factors occurred independently of each other and that they also occurred concurrently. The model currently does not account for time or ordering of factors and did not have enough data to control and evaluate correlations or interactions between factors, which may affect external validity.
    Lastly, this thesis suggests areas for future research including filling gaps in baseline surveillance data, a need for increased transparency about the prevalence of broiler chicken production types and extending the model past the retail node to include consumer practices and human health outcomes.

  • Subjects / Keywords
  • Graduation date
    Fall 2022
  • Type of Item
  • Degree
    Master of Science
  • DOI
  • License
    This thesis is made available by the University of Alberta Library with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.