Dissertation
ECOLOGICAL METRICS AND BAYESIAN ANALYSIS OF ANTIMICROBIAL RESISTANCE AND CARBOHYDRATE FERMENTATION PHENOTYPES OF FECAL E.COLI SHED BY DAIRY CALVES AND COWS
Doctor of Philosophy (PhD), Washington State University
01/2018
Handle:
https://hdl.handle.net/2376/112399
Abstract
Antimicrobial resistance (AMR) in E. coli is known to persist in human and animal reservoirs in absence of antimicrobial selection pressure, which means that mitigation focused solely on prudent antimicrobial use, can be expected at best to only postpone the evolution of antimicrobial resistance. To protect human and animal health alike it is imperative that we take a multifaceted approach to AMR mitigation, by developing alternatives to antimicrobials and identifying strategies to prevent amplification and transmission of antimicrobial resistant E. coli. In dairy production systems, neonatal calves appear to be a reservoir of multidrug resistant E. coli, even in absence of previous antibiotic exposure. Consequently, they may be a critical control point for mitigating AMR on dairy farms. Because calves are immune-naïve they may also be at increased risk for AMR-associated morbidity and mortality. Motivated by these concerns, we aimed to apply a multifaceted approach in our research addressing AMR of E. coli on dairies.
This research combines ecological metrics and Bayesian analyses to investigate E. coli population structure on dairy farms. We focus on the potential relationships between AMR and E. coli carbon-source fermentation. The rationale for this stems from the direct observation that AMR is very low in adult cows indicating that as the rumen and hindgut develops, AMR E. coli are competitively excluded. Considering competition for carbohydrates in the gut is an important driver of gut microbial populations it stands to reason that the carbon-source metabolic repertoire of E. coli strains colonizing calves and cows may play important roles in AMR dynamics on dairies. In the latter part of this thesis we conduct a field-based clinical trial to investigate the potential benefits of supplementing neonatal dairy calves with complex carbohydrates, referred to as oligosaccharides (OS). The rationale behind this work stems from an extensive body of research demonstrating that naturally derived OS possess pathogen binding properties, analogous to passive immunity, as well as prebiotic effects on gut microbial communities.
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Details
- Title
- ECOLOGICAL METRICS AND BAYESIAN ANALYSIS OF ANTIMICROBIAL RESISTANCE AND CARBOHYDRATE FERMENTATION PHENOTYPES OF FECAL E.COLI SHED BY DAIRY CALVES AND COWS
- Creators
- Diana Marie Short
- Contributors
- William M Sischo (Advisor)Margaret A Davis (Committee Member)Dale A Moore (Committee Member)Thomas E Besser (Committee Member)
- Awarding Institution
- Washington State University
- Academic Unit
- Veterinary Medicine, College of
- Theses and Dissertations
- Doctor of Philosophy (PhD), Washington State University
- Number of pages
- 164
- Identifiers
- 99900581423101842
- Language
- English
- Resource Type
- Dissertation