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Background People with COPD have been reported to bear a distinct airway microbiota from healthy individuals based on bronchoalveolar lavage (BAL) and sputum samples. Unfortunately, the collection of these samples involves relatively invasive procedures and is resource-demanding, limiting its regular use. Non-invasive samples from the upper airways could constitute an interesting alternative, but its relationship with COPD is still underexplored. We examined the merits of saliva to identify the typical profile of COPD oral bacteria and test its association with the disease. Methods Outpatients with COPD and age-sex matched healthy controls were recruited and characterised based on clinical parameters and 16S rRNA profiling of oral bacteria. A clustering analysis based on patients’ oral bacteria beta-diversity and logistic regressions were performed to evaluate the association between oral bacteria composition and COPD. Results 128 individuals participated (70 patients and 58 controls). Differential abundance analyses showed differences in patients comparable to the ones previously observed in samples from the lower respiratory tract, i.e., an increase in Proteobacteria (particularly Haemophilus) and loss of microbiota diversity. An unsupervised clustering analysis separated patients in two groups based on microbiota composition differing significantly in the frequency of patients hospitalized due to severe acute exacerbation of COPD (AECOPD) and in the frequency of GOLD D patients. Furthermore, a low frequency of Prevotella was associated with a significantly higher risk of recent severe AECOPD and of being GOLD D. Conclusion Salivary bacteria showed an association with COPD, particularly with severe exacerbations, supporting the use of this non-invasive specimen for future studies of heterogeneous respiratory diseases like COPD.

People with COPD present microbiota dysbiosis. Clinical implications of this finding are still unknown and need validation. Here, we tested the association between salivary microbiota and COPD and its ability to discriminate different types of patients. 67 patients with COPD (57male, 68±9y, FEV1pp 48±19, GOLD A-12, B-31, C-5, D-19) were characterised based on sociodemographic, anthropometric, clinical data and 16S rRNA profiling of their salivary microbiota. An unsupervised clustering analysis based on patients’ beta diversity was performed to query its relationship with the disease. Two major clusters (comprising 90% of individuals) differing drastically in severity were observed. Cluster1 aggregated all patients hospitalized in the previous year due to acute exacerbations, 71% of GOLD D patients and included a higher frequency of patients under oxygen therapy and heavier smoking history than Cluster 2 (Fig 1A). Furthermore, Cluster1 had a lower microbiota diversity (MW-U, p=0.008) (Fig 1B) and was enriched in Proteobacteria or Firmicutes, particularly Streptococcus. In contrast, Cluster2 was significantly enriched in Bacteroidetes, particularly Alloprevotella and Prevotella (Fig 1C). Saliva’s microbiota showed a strong association with COPD, especially in terms of severe exacerbations, supporting the use of salivary microbiota for further studies in this population. published

Bronchoalveolar lavage (BAL) and sputum samples are commony used to provide valuable information on airway microbiota of COPD but they are too invasive to be routinely collected. An interesting alternative would be the use of non-invasive samples from the upper airways but its validation is still lacking. Here, we have explored the merits of saliva to identify the typical profile of COPD microbiota. 70 patients with COPD (60 male, 68±9y, BMI 25.5±3.5, FEV1pp 48±16, GOLD A-12, B-32, C-5, D-21) and 50 healthy matched controls (42 male, 67±8y, BMI 27.6±3.8, FEV1pp 103±17) were characterised based on sociodemographic, anthropometric, clinical parameters and 16S rRNA profiling of their salivary microbiota. Microbiota composition was significantly different between healthy individuals and patients with COPD and could also descriminate moderate from severe patients. Healthy individuals were enriched in Alloprevotella and Prevotella, both Bacteroidetes’ genera, whereas moderate patients were enriched in Granullicatella and Lachnoanaerobaculum (Firmicutes) and severe patients were significantly enriched in Haemophilus (Proteobacteria) (Fig1.A). Furthermore, patients showed a significantly less diverse microbiota than healthy individuals (MW-U, p=0.001) (Fig1.B). Our results corroborate the findings reported previously using BAL and sputum samples encouraging further exploration of salivary microbiota as a potential disease biomarker. published

Chronic obstructive pulmonary disease (COPD) is influenced by environmental factors, such as indoor/outdoor contaminants. However, patients’ views on environmental exposure are little-known and this is an often-neglected topic in psychoeducational sessions in pulmonary rehabilitation (PR). We explored the views of patients with COPD about indoor/outdoor environment and its influence on their health and the impact of an environmental educational session within PR, on their daily living. Focus groups were conducted before and after community-based PR. An educational session was designed and included in PR after the first focus group. Data were analysed with thematic analysis. Four focus groups were conducted with 31 patients with COPD (71±8y; 74%male; FEV1 48±17pp; 45% GOLD2; 58% GOLDB). Prior to PR, 3 themes emerged: 1) “just seeing the tip of the iceberg” since some awareness existed but a feeling of probably not knowing the real impact was shared; 2) “feeling resigned” where patients acknowledged having poor strategies to avoid contaminants and felt there was little they could do; and 3) “willingness to learn” as they reported the need for an educational session to improve their knowledge on environmental exposures. After PR, 2 themes were found: 1) “gratefulness” where patients shared that the session was helpful for themselves and significant others; and 2) “personal change”, where patients expressed how their behaviour changed towards more health-enhancing strategies to deal with contaminants. Environmental education within PR is valued by patients and leads to specific behaviour changes to deal with contaminants’ exposure. Further attention to this topic is warranted. published