Modulation of Candida albicans-associated denture biofilms by environmental and microbial factors

Williams, Megan 2023. Modulation of Candida albicans-associated denture biofilms by environmental and microbial factors. PhD Thesis, Cardiff University. Item availability restricted.

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Abstract

Candida albicans has been designated as a critical priority in the WHO fungal pathogens list to guide research, development and public health action (World Health Organization 2022). Candida-associated denture stomatitis affects approximately 65-75% of denture wearers and is one of the most common forms of candidosis. The predominant species involved is C. albicans, an opportunistic pathogen problematic for people who are immunocompromised or have implanted medical devices. The overall aim of this research was to explore the impact of surface conditioning (Chapter 2), surface topography (Chapter 3) and bacterial presence (Chapters 4 and 5), on the behaviour of C. albicans in in vitro biofilms. It was evident from the surface conditioning investigations that both the quantity and morphology of C. albicans in biofilms could be modulated by these variables in a strain dependent manner. Denture material surfaces with significant differences in surface roughness were created and shown to affect the quantity of C. albicans present. C. albicans cells were clearly observed in the topological features in the surfaces. Dual species of C. albicans and relevant oral Streptococcus species resulted in increased C. albicans quantity though the same effect was not observed in experiments with spent media from the streptococcal species, suggesting microbial cells were required to be present. Based on studies of bacterial association with C. albicans hyphae, physical binding of some bacteria with the ALS3 protein was evident which could promote interactions. More complex saliva-derived biofilms were shown to influence C. albicans quantity and morphology, and differences between biofilms from separate individuals were explored using metagenomic sequencing. If such in vitro effects translate to the in vivo environment, knowledge of these effects may provide insight into how the usually commensal organism C. albicans could become pathogenic and inform future treatment and management strategies for Candida-associated denture stomatitis.

Item Type:	Thesis (PhD)
Date Type:	Completion
Status:	Unpublished
Schools:	Dentistry
Subjects:	Q Science > QR Microbiology R Medicine > RK Dentistry
Funders:	BBSRC, GSK/Haleon
Date of First Compliant Deposit:	25 August 2023
Last Modified:	11 Sep 2023 11:29
URI:	https://orca.cardiff.ac.uk/id/eprint/162048

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