Chapters authored
Extracellular Vesicles and Their Role in Staphylococcus aureus Resistance and Virulence
Staphylococcus aureus is a pathogen of great importance to clinical and veterinary medicine. Recently, there has been a growing interest in S. aureus extracellular vesicles (EVs) in the pathogenesis of this bacterium. Released by living cells into the extracellular milieu, EVs are membranous structures carrying macromolecules such as proteins, nucleic acids, and metabolites. These structures play several physiological roles and are, among others, considered a mechanism of intercellular communication within S. aureus populations but also in trans kingdom interactions. S. aureus EVs were shown to transport important bacterial survival and virulence factors, such as β-lactamases, toxins, and proteins associated with bacterial adherence to host cells, and to trigger the production of cytokines and promote tissue inflammation. In this chapter, we will review the main studies regarding S. aureus EVs, including their composition and roles in host-pathogen interactions, and the possible applications of EVs for vaccines and therapy development against staphylococcal infections.
Part of the book: Insights Into Drug Resistance in Staphylococcus aureus
Propionibacterium freudenreichii: General Characteristics and Probiotic Traits
Propionibacterium freudenreichii is a Gram-positive dairy probiotic bacterial species that has been used as a ripening starter in the production of Swiss-type cheese for a long time. It has been exploited for the optimization of cheese production, including ripening capacities and aroma compounds production, but also for the production of vitamin B12 and organic acids. Furthermore, it has emerged in the probiotics landscape owing to several beneficial traits, including tolerance to stress in the gastrointestinal tract, adhesion to host cells, anti-pathogenic activity, anticancer potential and immunomodulatory properties. These beneficial properties have been confirmed with in vitro and in vivo investigations, using several omics approaches that allowed the identification of important molecular actors, such as surface proteins, short-chain fatty acids and bifidogenic factors. The diversity within the species was shown to be an important aspect to take into consideration, since many of these properties were strain-dependent. New studies should dive further into the molecular mechanisms related to the beneficial properties of this species and of its products, while considering the complexities of strain diversity and the interactions with the host and its microbiota. This chapter reviews current knowledge on the possible impact of P. freudenreichii on human health.
Part of the book: Prebiotics and Probiotics