Microorganisms are ubiquitous in the environment. Some may cause disease, but most do not. More than 100 trillion live within the human gut, mouth, skin and other mucosal surfaces. Studies involving human-associated microorganisms suggest that large numbers of microorganisms assist in maintaining processes necessary for a healthy body. Changes in the human microbiome, however, may result in disease, or contribute to prevention. At the Winter 2015 Avant Institute Symposium, experts in microorga...