Abstract

A complex community of microorganisms inhabits the mammalian gastrointestinal tract from mouth to anus, but the colon is, by far, the main site of this microbial colonization [1]. Over the last 20–25 years, our knowledge on the complexity of this microbiota has increased considerably. Paramount to such a progress is the development and validation of a diversity of new molecular-based microbiological methodologies that have provided unequivocal evidence of composition [2–4]: