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Impact of food, environmental and pharmaceutical antimicrobials on the gut microbiome
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Date
2024
Authors
Walsh, Lauren
Journal Title
Journal ISSN
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Publisher
University College Cork
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Abstract
This thesis is concerned with antimicrobials (both protein, peptide and chemical based) and their role in the gut microbiome from a functional and compositional perspective, as well as the isolation and development of new bacteriocins against pathogenic bacteria of interest.
Pharmaceutical antimicrobials such as antibiotics, bacteriocins, phages and their endolysins are discussed in chapters 1, 3, 4 and 5. Chapter 1 describes antibiotic alternatives that could potentially be used to treat nosocomial methicillin resistant Staphylococcus aureus (MRSA) infection. Some alternative options include bacteriocins, phages and phage lysins. In Chapter 5, the antibiotics fidaxomicin and vancomycin were compared with the two bacteriocins, thuricin CD and nisin, as potential therapeutics to combat CDI and to assess their overall impact on the gut microbiome. Chapters 3 and 4 specifically discuss the isolation of novel bacteriocin producing bacteria. Chapter 3 describes the isolation of two bacteriocin producing strains termed AS1 and AS2. Chapter 4 outlines the isolation of Paenibacillus ottowii FAA_942_34, which demonstrated activity against IBD-associated bacteria.
Environmental antimicrobials and food antimicrobials were examined in chapters 2, 6 and 7. Chapter 2 is a review focusing on the herbicide glyphosateTM, specifically focusing on the compositional and functional changes that glyphosate elicits in the gut microbiome. In chapter 6, glyphosate and four food preservatives were analysed for their effect on the gut microbiome. In Chapter 7, the heavy metal cadmium was used as a selective agent to identify transformants acquiring pJOS01. Following electroporation of pJOS01 into Staphylococcus aureus RN4220, a smaller 21 Kb plasmid termed pJOS02 was recovered in transformants. Formation of pJOS02 from pJOS01 is thought to result from the presence of inverted repeat regions at either end of pJOS02.
Overall, the results of this thesis outline a variety of antimicrobials and their effect on the gut microbiome and their potential as therapeutics. This research builds on the growing amount of knowledge around the antimicrobials, the gut microbiome and the effect antimicrobials have on the composition and functionality of the gut microbiome.
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Keywords
Antimicrobial , Gut microbiome , Bacteriocin , Food preservative , Glyphosate
Citation
Walsh, L. 2024. Impact of food, environmental and pharmaceutical antimicrobials on the gut microbiome. PhD Thesis, University College Cork.