The human microbiome: at the interface of health and disease

Abstract

Interest in the role of the microbiome in human health has burgeoned over the past decade with the advent of new technologies for interrogating complex microbial communities. The large-scale dynamics of the microbiome can be described by many of the tools and observations used in the study of population ecology. Deciphering the metagenome and its aggregate genetic information also can be used to understand the functional properties of the microbial community. Both the microbiome and metagenome probably have important functions in health and disease; their exploration is a frontier in human genetics.

Defining the gut microbiota in individuals with periodontal diseases: an exploratory study

“…Other investigations have shown that reduced alpha diversity is a reliable indicator of disease-associated dysbiosis [1,54–56], corroborating our results. In relation to beta diversity, it was not possible to clearly distinguish individuals with distinct clinical status based on the composition of the gut microbiota.…”

“…Disturbance on human microbiota colonizing the various body sites has been implicated in a wide range of microbiome-related inflammatory diseases [1–5]. Among those, periodontal diseases are complex polymicrobial inflammatory diseases associated with dysbiosis of the dental biofilm that induces a long-lasting chronic inflammation of the periodontal supporting tissues, leading to alveolar bone destruction, and eventual tooth loss [6].…”

The regulation of host defences to infection by the microbiota

“…Colonization begins in earnest after birth, with the mother normally providing the bacterial inoculum that seeds the microbiota of her offspring 4, 5. Initially, the bacterial communities of each surface have a similar taxonomic composition, but through the course of infancy each surface develops a microbiota with a unique composition that stabilizes during adulthood 2, 6, 7. In the adult gastrointestinal tract, the microbiota is dominated by bacteria from two phyla: the Bacteroidetes and Firmicutes 3.…”

“…It is thought that many of the members of the Bacteroidetes and Firmicutes are only found within the mammalian gastrointestinal tract, suggesting that these organisms have become specialized to live within this niche and have evolved to form a stable, long‐term interaction with their host 1. Other host surfaces colonized by large bacterial communities include the airway and skin 2, 6. The upper airway has a rich microbial community dominated by bacteria from the Firmicute, Actinobacteria and Proteobacteria phyla,8 with the skin being home to mainly Actinobacteria, Proteobacteria and Firmicutes 2.…”

“…Other host surfaces colonized by large bacterial communities include the airway and skin 2, 6. The upper airway has a rich microbial community dominated by bacteria from the Firmicute, Actinobacteria and Proteobacteria phyla,8 with the skin being home to mainly Actinobacteria, Proteobacteria and Firmicutes 2. Throughout life, diet9, 10 and host genetics11, 12 are thought to play a role in shaping microbiota composition, with infection13, 14, 15 and antibiotic treatment16, 17, 18, 19 being examples of major causes of microbiota disruption (dysbiosis).…”