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Staphylococcus epidermidis, Host Immune Factors and Medical Device Infections / NERISSA THOMAS

Swansea University Author: NERISSA THOMAS

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Abstract

Medical device infections, commonly caused by S. epidermidis are difficult to treat due to the formation of biofilms on the medical device surface which protect S. epidermidis against host immune defences and antibiotics. This project aimed to further our understanding of the interactions between S....

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Published: Swansea, Wales, UK 2023
Institution: Swansea University
Degree level: Master of Research
Degree name: MSc by Research
Supervisor: Harris, Llinos G. and Wilkinson, Thomas S.
URI: https://cronfa.swan.ac.uk/Record/cronfa63583
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first_indexed 2023-06-05T10:31:21Z
last_indexed 2023-06-05T10:31:21Z
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spelling v2 63583 2023-06-05 Staphylococcus epidermidis, Host Immune Factors and Medical Device Infections e94e33158e27d1aa5eb199fdff561285 NERISSA THOMAS NERISSA THOMAS true false 2023-06-05 Medical device infections, commonly caused by S. epidermidis are difficult to treat due to the formation of biofilms on the medical device surface which protect S. epidermidis against host immune defences and antibiotics. This project aimed to further our understanding of the interactions between S. epidermidis, and fibroblasts or macrophages in the presence of uncoated or whole-blood coated titanium (Ti) and titanium alloy (TiAlV) discs. S. epidermidis and fibroblasts/macrophages were cocultured on Ti or TiAlV discs for 6 and 24 h. The resulting samples were then analysed in one of three ways, 1) supernatant assayed for fibroblast/macrophage cytokine expression; 2) bacterial RNA extracted to analyse transcription of adhesion and biofilm associated genes; 3) samples prepared for visualisation using confocal microscopy and scanning electron microscopy. Cytokine analysis found increased expression of various cytokines involved in the regulation of immune responses to injury and infection, including IL-1β, MCP-1 and MIP-3α or IL-8, MIF, IFN-γ by macrophages and fibroblasts respectively on uncoated Ti, and IL-1α, IL-6 and TNF-α by fibroblasts on pre-coated Ti. RT-qPCR of S. epidermidis found that gene transcription differed depending on disc or culturing conditions, indicating that both host cells and surfaces influence attachment and biofilm formation. Microscopy showed the adherence of S. epidermidis, macrophages and fibroblasts to discs in monoculture and co-culture, however, by 24 h, fibroblasts detached implying that S. epidermidis impacts the ability of fibroblasts to survive on the discs. To conclude, the results suggest that Ti or TiAlV discs, S. epidermidis and macrophages/fibroblasts interact with and affect each other during the initial stages of infection, with S. epidermidis pathogenesis being further influenced by the presence of host factors. This work is clinically relevant and directly translational to improving the treatment and diagnosis of medical device infections, which remain a burden on the NHS. E-Thesis Swansea, Wales, UK Staphylococcus epidermidis, medical device infection, Titanium, Titanium alloy, immune response, ELISA, biofilms, co-culture, Microscopy 6 3 2023 2023-03-06 COLLEGE NANME COLLEGE CODE Swansea University Harris, Llinos G. and Wilkinson, Thomas S. Master of Research MSc by Research The Robert Mathys Foundation The Robert Mathys Foundation 2023-10-27T16:06:24.6347097 2023-06-05T11:27:31.2883382 Faculty of Medicine, Health and Life Sciences Swansea University Medical School - Biomedical Science NERISSA THOMAS 1 63583__27707__437c31f9eb8d47b1ae2e302b39e6d488.pdf 2023_Thomas_NE.final.63583.pdf 2023-06-05T11:32:59.7321362 Output 9711419 application/pdf E-Thesis – open access true Copyright: The Author, Nerissa E. Thomas, 2023. true eng
title Staphylococcus epidermidis, Host Immune Factors and Medical Device Infections
spellingShingle Staphylococcus epidermidis, Host Immune Factors and Medical Device Infections
NERISSA THOMAS
title_short Staphylococcus epidermidis, Host Immune Factors and Medical Device Infections
title_full Staphylococcus epidermidis, Host Immune Factors and Medical Device Infections
title_fullStr Staphylococcus epidermidis, Host Immune Factors and Medical Device Infections
title_full_unstemmed Staphylococcus epidermidis, Host Immune Factors and Medical Device Infections
title_sort Staphylococcus epidermidis, Host Immune Factors and Medical Device Infections
author_id_str_mv e94e33158e27d1aa5eb199fdff561285
author_id_fullname_str_mv e94e33158e27d1aa5eb199fdff561285_***_NERISSA THOMAS
author NERISSA THOMAS
author2 NERISSA THOMAS
format E-Thesis
publishDate 2023
institution Swansea University
college_str Faculty of Medicine, Health and Life Sciences
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hierarchy_top_id facultyofmedicinehealthandlifesciences
hierarchy_top_title Faculty of Medicine, Health and Life Sciences
hierarchy_parent_id facultyofmedicinehealthandlifesciences
hierarchy_parent_title Faculty of Medicine, Health and Life Sciences
department_str Swansea University Medical School - Biomedical Science{{{_:::_}}}Faculty of Medicine, Health and Life Sciences{{{_:::_}}}Swansea University Medical School - Biomedical Science
document_store_str 1
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description Medical device infections, commonly caused by S. epidermidis are difficult to treat due to the formation of biofilms on the medical device surface which protect S. epidermidis against host immune defences and antibiotics. This project aimed to further our understanding of the interactions between S. epidermidis, and fibroblasts or macrophages in the presence of uncoated or whole-blood coated titanium (Ti) and titanium alloy (TiAlV) discs. S. epidermidis and fibroblasts/macrophages were cocultured on Ti or TiAlV discs for 6 and 24 h. The resulting samples were then analysed in one of three ways, 1) supernatant assayed for fibroblast/macrophage cytokine expression; 2) bacterial RNA extracted to analyse transcription of adhesion and biofilm associated genes; 3) samples prepared for visualisation using confocal microscopy and scanning electron microscopy. Cytokine analysis found increased expression of various cytokines involved in the regulation of immune responses to injury and infection, including IL-1β, MCP-1 and MIP-3α or IL-8, MIF, IFN-γ by macrophages and fibroblasts respectively on uncoated Ti, and IL-1α, IL-6 and TNF-α by fibroblasts on pre-coated Ti. RT-qPCR of S. epidermidis found that gene transcription differed depending on disc or culturing conditions, indicating that both host cells and surfaces influence attachment and biofilm formation. Microscopy showed the adherence of S. epidermidis, macrophages and fibroblasts to discs in monoculture and co-culture, however, by 24 h, fibroblasts detached implying that S. epidermidis impacts the ability of fibroblasts to survive on the discs. To conclude, the results suggest that Ti or TiAlV discs, S. epidermidis and macrophages/fibroblasts interact with and affect each other during the initial stages of infection, with S. epidermidis pathogenesis being further influenced by the presence of host factors. This work is clinically relevant and directly translational to improving the treatment and diagnosis of medical device infections, which remain a burden on the NHS.
published_date 2023-03-06T16:06:22Z
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score 11.035634

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