Analisi dei fattori che influenzano la colonizzazione e la composizione del microbiota intestinale umano

The entangled and heterogeneous community of microorganisms inhabiting the human gastrointestinal tract (GIT) is the so-called gut microbiota. This intricated ecosystem has evolved over time to establish a symbiotic relationship with the human host, providing mutual advantages to both. Given the continuous molecular interactions between bacteria and the human being, which play a crucial role in maintaining overall health, substantial research efforts have been directed toward deciphering the microbial composition and its functional implication of the gastrointestinal microbiome. This Ph.D. thesis aims to investigate and elucidate some of the factors influencing the colonization and composition of the gut microbiota throughout life and how these influence the modulation of this complex ecosystem. In particular, the first section of this Ph.D. thesis focuses on examining how bifidobacterial intrinsic genetic factors, such as specific genes involved in the interaction’s mechanisms, impact the colonization and persistence of this species within the intestinal environment. Specifically, the bifidobacterial intricate molecular mechanisms involved in their survival within a competitive intestinal niche are investigated. Additionally, the second section of this thesis highlights the influence of extrinsic factors, such as insulin, a hormone typically presents in healthy women’s breast milk, on the colonization mechanisms of <Bifidobacterium bifidum> PRL2010 in the gut. Finally, we have provided novel insights into the emerging field of pharmacomicrobiomics, where the effects of six different oral corticosteroids on the composition of ten artificial gut microbiota (AGM) were examined. Such study explores how the diverse compositions of AGMs influence the metabolism of the same drugs.