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Humans live in symbiosis with clusters of microbes in various parts of the body ranging from the skin, gut, oral cavity, vagina, and other areas exposed to the environment. This community can weigh up to 2 kg and are composed of roughly 100 trillion microorganisms, including 1000 different species of known bacteria with more than 3 million genes (4). These bacterial communities are primary constituents of the microbiome that encompasses the complete genetic potential of a bacterial population as well as the products of the microbiota (microbial taxa) and host environment. The majority of the microbiota is harbored in the large intestine and undergoes stages during the host's life cycle with the most dynamic time being infancy.

It is recognized that one third of our gut microbiota is common to most humans whereas the other two thirds are specific to the individual (34). As a result, the microbiota can provide a …