Influence du microenvironnement sur la virulence et la formation de biofilm de Cutibacterium acnes.

Abstract : Acne vulgaris is one of the most common skin diseases. Its pathogenesis is still unclear but Cutibacterium acnes (former Propionibacterium acnes) is considered as essential for its development. This bacterium is characterized by high genomic variability and some strains as ribotype 4 and 5 (RT4 and RT5) strains are highly associated with acne whereas RT6 strains are enriched in healthy skin. The physiological differences between these C. acnes types were evaluated dependently of their environment (culture media). Moreover, a link between acne and stress has been described, the use of preservative-free-cosmetics is burgeoning and bacteria can react to local factors by important metabolic changes. In this respect, two catecholamines and two cosmetic compounds were also tested. This study shows that the different C. acnes types are adapted to different ecological niches: acneic strains are adapted to sebaceous glands whereas non-acneic strains are more adapted to the skin surface and the upper hair follicle. Moreover, the acneic type seems associated to a more important inflammatory potential, which consolidates its possible implication in acne. The catecholamines can stimulate its biofilm formation and C. acnes treated by these molecules can stimulated the lipogenesis in sébocytes. Then, this study highlights the existence of a link between stress and the potential role of C. acnes in acne. Elsewhere, this study shows that the biofilm of C. acnes can be inhibited by Uriage thermal water and/or a rhamnose-rich polysaccharide (PS291®).
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Valérie Borrel. Influence du microenvironnement sur la virulence et la formation de biofilm de Cutibacterium acnes.. Bactériologie. Normandie Université, 2019. Français. ⟨NNT : 2019NORMR035⟩. ⟨tel-02313531⟩

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