The human organism is a complex structure composed of cells belonging to all three domains of life on Earth, Eukarya, Bacteria and Archaea, as well as their viruses. Bacterial cells of more than a thousand taxonomic units are condensed in a particular functional collective domain, the intestinal microbiome. The microbiome constitutes the last human organ under active research. Like other organs, and despite its intrinsic complexity, the microbiome is readily inherited, in a process probably involving 'small world' power law dynamics of construction in newborns. Like any other organ, the microbiome has physiology and pathology, and the individual (and collective?) health might be damaged when its collective population structure is altered. The diagnostic of microbiomic diseases involves metagenomic studies. The therapeutics of microbiome-induced pathology include microbiota transplantation, a technique increasingly available. Perhaps a new medical specialty, microbiomology, is being born.
© 2012 The Authors. Clinical Microbiology and Infection © 2012 European Society of Clinical Microbiology and Infectious Diseases.