The human gut microbiota makes fundamental contributions to host metabolism and immune system. Therefore, perturbations in its composition, a process known as dysbiosis, have an important role in the development of several chronicle diseases, mainly intestinal inflammatory disorders. Culture-independent molecular methods are allowing scientific community to uncover substantive findings, thus giving a more detailed description of the human intestinal microbiota. This chapter presents a review on current metagenomic approaches, based on next-generation sequencing technologies, for investigating bacterial taxonomic classification and predictive function associated with the human gut in health and disease. In this context, we describe recent studies that have been trying to elucidate important alterations in microbiome composition across individuals according to delivery mode, aging, diet and medication that might be linked to susceptibility to immune-mediated diseases. A description of the main bacterial taxa and genes acting in dysbiosis during inflammation, focusing on chronic inflammatory bowel diseases and colorectal cancer, is also explored in this chapter.
Part of the book: Metagenomics for Gut Microbes