phs000633
Enrichment of lung microbiome with supraglottic taxa is associated with increased pulmonary inflammation
Background: The lung microbiome of healthy individuals frequently harbors oral organisms. Despite evidence that micro-aspiration is commonly associated with smoking-related lung diseases, the effects of lung microbiome enrichment with upper airway taxa on inflammation has not been studied. We hypothesize that the presence of oral microorganisms in the lung microbiome is associated with enhanced pulmonary inflammation.  Methods: We sampled bronchoalveolar lavage (BAL) from the lower airways of 29 asymptomatic subjects (9 never-smokers, 14 former-smokers and 6 current-smokers). We quantified, amplified, and sequenced 16S rRNA genes from BAL samples by qPCR and 454 sequencing. Pulmonary inflammation was assessed by exhaled nitric oxide (eNO), BAL lymphocytes and neutrophils.  Results: BAL had lower total 16S than supraglottic samples and higher than saline background. Bacterial communities in the lower airway clustered in two distinct groups that we designated... (for more see dbGaP study page.)