Interdisciplinary Perspectives on Infectious Diseases 
Volume 2008 (2008), Article ID 613979, 5 pages
doi:10.1155/2008/613979
Review Article

Conceptualizing Human Microbiota: From Multicelled Organ to Ecological Community

Betsy Foxman,1 Deborah Goldberg,2 Courtney Murdock,3 Chuanwu Xi,4 and Janet R. Gilsdorf1,5

 1Department of Epidemiology, University of Michigan, Ann Arbor, MI 48109, USA
2Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI 48109, USA
3School of Natural Resources and Environment, University of Michigan, Ann Arbor, MI 48109, USA
4Department of Environment Health Sciences, University of Michigan, Ann Arbor, MI 48109, USA
5Department of Pediatrics, University of Michigan, Ann Arbor, MI 48109, USA
Received 4 February 2008; Accepted 19 July 2008

Recommended by Thomas M. Schmidt

Abstract

The microbiota of a typical, healthy human contains 10 times as many cells as the human body and incorporates bacteria, viruses, archea, protozoans, and fungi. This diverse microbiome (the collective genomes of the microbial symbionts that inhabit a human host) is essential for human functioning. We discuss the unstated assumptions and implications of current conceptualizations of human microbiota: (1) a single unit that interacts with the host and the external environment; a multicelled organ; (2) an assemblage of multiple taxa, but considered as a single unit in its interactions with the host; (3) an assemblage of multiple taxa, which each interacts with the host and the environment independently; and (4) a dynamic ecological community consisting of multiple taxa each potentially interacting with each other, the host, and the environment. Each conceptualization leads to different predictions, methodologies, and research strategies.