Fig. 1
From: Acquisition and adaptation of the airway microbiota in the early life of cystic fibrosis patients
Theoretical acquisition and evolution of the microbiome in CF airways. In the early stage of CF, migration of bacteria from the nose and throat (considered as the mainland) will seed the lower airways. The lung microbiome in the early phase of CF resembles the one from the throat. Thus, migration, growth, and elimination of the microbiota with the throat as main source also initially is balanced as observed in healthy people. With aging, changes in the regional conditions (mucus, nutrients, pH, clearance, and immunity) lead to an unbalance in the equilibrium between migration and elimination thus favoring regional growth in the lower airways of typical or atypical CF pathogens. This overgrowth probably is not linked to major changes in the source niches (nose and throat), yet pathogens may originate from there. Microenvironment changes trigger the segregation of the lung’s microbiome from the throat’s microbiome creating a third independent microbiome in the airways