Human microbiota: The good, the bad and the ugly

In recent years, the development and the huge diffusion of Next Generation Sequencing (NGS)-based techniques has allowed the study of microbial communities at a previously unimaginable resolution level. Consequently, the knowledge of the role and functions of the human microbiota in various body sites has increased, identifying several fundamental roles for the microbiota in the development and maintenance of body homeostasis, also in relation to various ages of life. On the other hand, a number of microbiota qualitative and/or quantitative alterations have been associated with several diseases, and the trend is increasing. Since targeted interventions can modify the microbiota, the definition of its composition in physiological and pathological conditions acquires crucial importance for the development of new diagnostic tools and/or therapeutic approaches aimed at manipulating the microbiota. In this context, the definition of standardized protocols and common guidelines to study the microbiota, and therefore the role of Laboratory Medicine, appears to be fundamental for the diffusion of metagenomic analyses in diagnostic contexts and will acquire greater relevance in the near future.