In this doctoral dissertation, we investigated the effects of selected natural bioactive compounds and interspecies interactions on the adhesion, culturability, virulence-associated properties, and protein profile of Campylobacter jejuni. We evaluated the effects of selected fungal lectins, the monoterpenes linalool and linalyl acetate, and interactions with Lactococcus cremoris and Pseudomonas fragi. The effects were studied on abiotic and biotic model surfaces, Caco-2 cells, and using quantitative proteomics. Fungal lectins reduced C. jejuni adhesion in a surface-dependent manner, while selected lectins also reduced its adhesion to and invasion of Caco-2 cells. Linalool and linalyl acetate reduced the number of culturable biofilm cells on polystyrene and mucin type II and decreased invasion of Caco-2 cells, but observed changes in the protein profile of mature biofilm cells were not statistically significant. The effect of L. cremoris depended on the surface and incubation time; after 48 h, the culturability of C. jejuni decreased on polystyrene, whereas the culturability of L. cremoris decreased on mucin type II. The interaction with P. fragi was bidirectional and depended on the surface, temperature, atmospheric conditions, and incubation time. Both interspecies interactions caused extensive statistically significant changes in the protein profile of C. jejuni. The results show that the response of C. jejuni in biofilms strongly depends on the surface, the experimental model, and environmental conditions, highlighting the importance of studying multispecies biofilms for understanding its persistence throughout the agrifood chain.
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