The Gut Microbiome in Health and Disease

It was first speculated in 1885, by Louis Pasteur, that commensal microbes have profound effects on their host. Two seminal technological advances have each provided unheralded progress of the scientific endeavor to address this long-held hypothesis. The first was the development of our ability to derive and maintain germ-free rodents, which first and foremost demonstrated animals could survive in the complete absence of microbes; however, various aspects of host physiology are clearly different in the absence of microbes. The second has been the advent of culture-independent techniques (e.g. next-generation sequencing) that have been used in the last decade to identify the composition of bacteria, viruses, and fungi associated with the host in a myriad of normal and disease settings. As a result of the latter technique there has been a rapid expansion in the field of host-microbe interactions that include diverse physiological settings. The gut microbiome and its associated metabolites have been shown to be involved in obesity, autoimmune disorders, neurological diseases, cancer, childhood undernutrition, and immunity to both enteric and systemic infections among others. In light of the rapid expansion of the gut microbiome field we propose this Research Topic to bring increased awareness to the diverse effect of the gut microbiome on health and disease. The objective of this Research Topic is to collate a series of reviews, commentaries, and research articles on the effect of the gut microbiome in various disease settings including, but not limited to, autoimmunity, cancer, infectious diseases, and inflammatory bowel disease.