Scrip

SLIDE 1

* Investigation of the lung microbiome is a relatively new field. Although the lungs were classically believed to be sterile, recently published researches have identified microbial communities in the lungs.

* The lungs were initially omitted from the list of priority organ systems in the Human Microbiome Project (HMP), subsequent studies have since demonstrated that the lower respiratory tract is replete with diverse communities of bacteria both in health and in diseased states.

* The concentrations of bacteria in the alveoli and small airways are likely considerably less than that of the mouth or lower GI tract. These low absolute levels of bacterial biomass introduce specific challenges to the field.

* The microbiota of the gastrointestinal tract have profound influence on the development and maintenance of lung immunity and inflammation. Further study of gastrointestinal–respiratory interactions is likely to yield important insights into the pathogenesis of pulmonary diseases.

SLIDE 2

* Studies that have compared concurrently sampled upper and lower respiratory tract samples have found similar but distinct microbial communities. These results suggest that the respiratory tract is not, as traditionally discussed, comprised of discrete and independent compartments. More accurate model is instead that the respiratory tract is a single, but internally heterogenous, ecosystem extending from the nares to the alveoli that contains a continuous, and continuously varying, microbial topography.

* Microbiota from the upper airways are likely constantly introduced to the lower airways via direct mucosal extension and microaspiration during sleep, which is omnipresent and usually asymptomatic. Microbiota from the lower airways are constantly introduced to the upper airways via cilliary transport and cough, which occurs many times a day even in patients without respiratory complaints. Conflicting results suggest that the diversity of a...