Mapping the microbial communities of the human body

The Nov. 5 issue of Science reports that our bodies are home to countless microorganisms, and researchers say that results from a recent body-wide analysis of these diverse microbial communities could ultimately reveal how changes in those communities can cause (or prevent) diseases. Elizabeth Costello and colleagues surveyed microbes from up to 27 body sites including the gut, mouth, ears, nose, and up to 18 skin surfaces on a handful of healthy adults on four separate occasions. Their findings build upon previous research published in Science (Grice et al. 05/29/2009) and reveal that the actual body site has the greatest influence on the composition of microbial communities dwelling there—much more so than the progression of time or variation between individual people. These researchers also found that some skin locations, like the index finger or back of the knee, often harbored more diverse microbes than the gut or mouth. Their data emphasize the fact that our bodies’ personalized microbes remain relatively stable over time, and that they display predictable patterns of growth across our bodies. In subsequent experiments, the researchers transplanted microbial communities from one body site to another—and from one person to another—and found that environmental factors were even more strongly involved in shaping microbial communities at greasy skin sites, compared to dry skin sites. For example, forearm microbes did not grow as well on the forehead, but forehead microbes grew just fine on the forearm.

Article #26: "Bacterial Community Variation in Human Body Habitats Across Space and Time," by E.K. Costello; C.L. Lauber; M. Hamady; N. Fierer; R. Knight at University of Colorado in Boulder, CO; J.I. Gordon at Washington University School of Medicine in St. Louis, MO.