Analysis of the Human Gut Microbiome and Association With Disease

Abstract

Advances in DNA sequencing technology and bioinformatics methodology have led to a revolution in our understanding of the microorganisms that inhabit the human body. Distinctive populations of organisms belonging to each of the 3 domains of life, Archaea, Bacteria, and Eukarya, inhabit each body site.1 The communities of microorganisms are referred to as the microbiota. When considering the organisms and all of their related genomes, the term microbiome is used. The human gut microbiome is particularly unique in that it is home to an enormous number of bacteria, approximately 100 trillion bacteria cells, outnumbering the human cells by an estimated 10 fold and the human genome by 150 fold. We have co evolved to exist with our gut microbiota largely in a mutualistic relationship where we as hosts rely on these organisms for a number of key functions related to nutrition, education of the immune system, and prevention of infection by pathologic species. In turn, we provide our gut microbiota with a unique niche in which to live where we provide a source of nutrition to the microbiota in the form of mucus. Alteration of the microbiota composition associated with disease, known as dysbiosis, has been described in the gut for numerous disease processes including inflammatory bowel diseases (IBDs), metabolic disorders, cancer, and infection, particularly with Clostridium difficile infection (CDI), to name a few.