The Human Respiratory System and its Microbiome at a Glimpse

The recent COVID-19 pandemic promoted efforts to better understand the organizationof the respiratory microbiome and its evolution from birth to adulthood and how it interacts withexternal pathogens and the host immune system. This review aims to deepen understanding of theessential physiological functions of the resident microbiome of the respiratory system on human healthand diseases. First, the general characteristics of the normal microbiota in the different anatomicalsites of the airways have been reported in relation to some factors such as the effect of age, diet andothers on its composition and stability. Second, we analyze in detail the functions and compositionand the correct functionality of the microbiome in the light of current knowledge. Several studiessuggest the importance of preserving the micro-ecosystem of commensal, symbiotic and pathogenicmicrobes of the respiratory system, and, more recently, its relationship with the intestinal microbiome,and how it also leads to the maintenance of human health, has become better understood.