Factors Influencing the Growth and Hydrogen Sulfide Production of Bilophila wadsworthia, an Important Member of the Sulfite-Reducing Bacteria in the Gut

Davies, Jade Jennifer (2023) Factors Influencing the Growth and Hydrogen Sulfide Production of Bilophila wadsworthia, an Important Member of the Sulfite-Reducing Bacteria in the Gut. Doctoral thesis, University of East Anglia.

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Abstract

Background: Sulfate-reducing bacteria (SRB) reduce sulfate to yield H2S and are commonly found in the human gut. Excess H2S has been linked to gut inflammation and is implicated in inflammatory disease pathogenesis. B. wadsworthia, a unique SRB member, is correlated with deleterious gut inflammation and disease; despite this, B. wadsworthia is present in the commensal gut microbiota of many healthy individuals. Enhancing our understanding of the factors influencing the abundance and H2S production of B. wadsworthia is a valuable research goal.

Objectives: This thesis aimed to investigate the effect of other gut microbiota members on the abundance and H2S production of B. wadsworthia.

Approaches: B. wadsworthia was co-cultured with the common gut commensals B. thetaiotaomicron and E. faecium. The differential gene expression of the bacterial strains using transcriptomics and the differential metabolome of the cultures using untargeted metabolomics was investigated to unravel the underlying mechanisms behind the microbial interactions observed.

Results: B. thetaiotaomicron significantly increased B. wadsworthia’s H2S production in co-culture; this interaction was dependent upon B. thetaiotaomicron viability and physical proximity between the strains. In co-culture, B. wadsworthia’s production of sulfite from taurine was decreased. Additionally, B. thetaiotaomicron-derived indole production was decreased. E. faecium significantly inhibited B. wadsworthia’s growth, which is at least partially mediated via lactic acid production. In silico genome screening of E. faecium strains revealed the presence of biosynthetic clusters for bacteriocins and absence of clinically-important AMR genes and virulence factors, supporting the potential use of these strains as anti-B. wadsworthia probiotics.

Conclusion: We hypothesise that in B. thetaiotaomicron and B. wadsworthia co-culture, co-operative metabolism of sulfate to H2S via an APS intermediate may permit excess H2S production by B. wadsworthia. E. faecium strains strongly inhibited B. wadsworthia’s growth in vitro, showing early promise for use of E. faecium as a potential anti-B. wadsworthia probiotic.

Item Type:	Thesis (Doctoral)
Faculty \ School:	Faculty of Science > School of Biological Sciences
Depositing User:	Chris White
Date Deposited:	07 May 2024 07:58
Last Modified:	07 May 2024 07:58
URI:	https://ueaeprints.uea.ac.uk/id/eprint/95063
DOI:

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