Oral microbiome and lung health

Background: Lung health might be influenced by oral bacteria through micro-aspiration and transfer of inflammatory mediators from the oral mucosa. Aim: To describe the association between oral bacteria and lung function in a healthy population from Bergen, Norway. Methods: Samples of gingival fluid were collected concurrently with spirometry in 288 adults (52% males, median age 28 years) from the RHINESSA study, Bergen centre. Bacterial DNA from the 16S rRNA gene were isolated from gingival fluid, sequenced by Illumina® and assigned bacterial taxonomy by the Human Oral Microbiome Database. Differential abundance in the gingival microbiome by FEV1 and FVC percent predicted was evaluated by the Analysis of Composition of Microbiomes methodology with 5% False Discovery Rate, adjusting for weight, education, smoking and asthma medication. Results: We identified 148 bacteria genera in the gingival fluid samples. 12 genera, accounting for 4.5% of the total gingiva microbiota, showed increased relative abundance with lower FEV1. The main contributors were Rothia spp. (2.4%) and Enterococcus spp. (1.2%). Among the 12 genera associated with FEV1, 6 genera (0.8% of the gingiva bacterial community) were also associated with lower FVC, with Propionibacterium spp. (0.6%) as the main contributor. Additionally 6 genera were associated with lower FVC; these contributed to Conclusion: High levels of Rothia, Propionibacterium and Enterococcus genera were associated with lower lung function, FEV1 in particular. Rothia species are implicated in lung disease and with periodontitis, while Propionibacterium and Enterococcus include known cariogenic pathogens. Thus, the main contributors to lower lung function are known oral or lung pathogens.