[The human microbiome].

The complex microbial populations that colonize the human body form the human microbiome. The human microbiota may contain 1014) cells, an order of magnitude greater than the number of the human cells, and can express 100 times more genes than the human genome. The metagenome is the collective genomes of the human and its microbial flora. Major international colLaborative efforts currently explore the diverse human microbiomes from five different body areas: the nasopharyngeal, gastrointestinal and female urogenital tracts, the oral cavity and the skin. Defining the complexity of the human microbiome in health and disease will enhance the understanding of multiple pathological mechanisms and facilitate the development of novel diagnostic tools and therapeutic interventions.