No abstract

The human body is host to 10 13 to 10 14 microbial organisms. The vast majority of these organisms are bacteria although viruses and fungi are also present at considerable amount and diversity. The gut is the main site of microbial colonization harboring a complex composition of bacteria referred to as the intestinal microbiota or sometimes as the intestinal microbiome. 1 Specifying the definition of the human microbiome has been complicated by confusion about terminology: "microbiota" (the microbial taxa associated with humans) and "microbiome" (the catalog of these microbes and their genes) are often used interchangeably. 2