Abstract
BACKGROUND: Culture independent methods of molecular detection of microbiome have shown the polymicrobial nature of respiratory infections in cystic fibrosis, with pathogenic agents undetectable in conventional culture methods. Composition and diversity of the airway microbiome are still poorly understood. METHODOLOGY: This study evaluated the airway microbiome in 31 adult cystic fibrosis patients via the analysis of 16S rRNA se- quences by next generation sequencing. RESULTS: Staphylococcus, Streptococcus and Corynebacterium were the most abundant genera in the middle meatus, and Pseudo- monas, Haemophilus and Prevotella were the most abundant in sputum. In patients with advanced disease (FEV1< 50%), there was an increase in the prevalence of Pseudomonas in both sample types when studied separately. In each patient, in a paired analysis, the sputum and middle meatus showed similar microbiome composition in mild or moderate disease (FEV1≥ 50%). In patients with severe lung disease, the relative abundance of Pseudomonas had a positive correlation in both collection sites. CONCLUSIONS: This is the first Brazilian study to evaluate the airway microbiome in cystic fibrosis patients. Our findings agree with those in the international literature and indicate the role of Pseudomonas in the sputum and middle meatus in patients with advanced disease.
Highlights
In Cystic fibrosis (CF), the mucosal surface of the airways exhibits increased mucus viscosity and reduced mucociliary clearance . [1,2] There is a predisposition toward infection by Staphylococcus aureus and Pseudomonas aeruginosa[3], which is associated with a decline in pulmonary function, the main cause of mortality . [4,5] Chronic colonization by P. aeruginosa occurs most often up until the third decade of life
Microbiome and pulmonary function - Severity of lung disease Middle meatus It was observed that the nasal middle meatus of patients with severe lung disease exhibited, on average, a greater abundance of Staphylococcus, Streptococcus and Stenotrophomonas, as well as a smaller abundance of Pseudomonas, Haemophilus and Corynebacterium, in comparison with those with mild to moderate lung disease (Figure S1)
On the other hand, when we evaluated the relative abundance of the genera in each individual, we found a different microbiome profile
Summary
In Cystic fibrosis (CF), the mucosal surface of the airways exhibits increased mucus viscosity and reduced mucociliary clearance . [1,2] There is a predisposition toward infection by Staphylococcus aureus and Pseudomonas aeruginosa[3], which is associated with a decline in pulmonary function, the main cause of mortality . [4,5] Chronic colonization by P. aeruginosa occurs most often up until the third decade of life. When comparing bacteria, such as S. aureus and P. aeruginosa, present in the nasal lavage and sputum of CF patients, there is a high concordance of genotypes, with evidence of cross-infection between the upper and lower airways [6]. CF patients subject to endonasal endoscopic surgery followed by antibiotic therapy attained a reduction in the occurrence of positive cultures for CF-related pathogens in the first year after surgery [8]. These and other studies [6,9] suggest that the paranasal sinuses function as reservoirs of pathogenic microorganisms. Culture independent methods of molecular detection of microbiome have shown the polymicrobial nature of respiratory infections in cystic fibrosis, with pathogenic agents undetectable in conventional culture methods. Composition and diversity of the airway microbiome are still poorly understood
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