Investigating the impact of polymicrobial interactions on fungal pathogenicity

Kousser, Courtney Alice (2019). Investigating the impact of polymicrobial interactions on fungal pathogenicity. University of Birmingham. Ph.D.

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Within the human body, microorganisms reside as part of a complex and varied ecosystem, where they rarely exist in isolation. Bacteria and fungi have co-evolved to develop elaborate and intricate relationships, utilising both physical and chemical communication mechanisms. Mucorales are filamentous fungi that are the causative agents of mucormycosis in immunocompromised individuals. Key to the pathogenesis is the ability to germinate and penetrate the surrounding tissues, leading to angioinvasion, vessel thrombosis, and tissue necrosis. It is currently unknown whether Mucorales participate in polymicrobial relationships, and if so, how this affects the pathogenesis. This project analyses the relationship between Mucorales and the microorganisms they may encounter. Here we show that Pseudomonas aeruginosa culture supernatants and live bacteria inhibit Rhizopus microsporus germination through the sequestration of iron. Therefore, treatment of P. aeruginosa in a patient could result in the release of this inhibition, leaving the patient more susceptible to an underlying fungal infection. However, P. aeruginosa responds to the presence of R. microsporus by enhancing siderophore production, which increases host mortality in a zebrafish co-infection model. This project highlights the complex competition between these organisms and the possible enhanced disease pathology when R. microsporus and P. aeruginosa meet in a host.

Type of Work: Thesis (Doctorates > Ph.D.)
Award Type: Doctorates > Ph.D.
Licence: All rights reserved
College/Faculty: Colleges (2008 onwards) > College of Life & Environmental Sciences
School or Department: School of Biosciences
Funders: Other
Other Funders: Darwin Trust of Edinburgh
Subjects: Q Science > QR Microbiology


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