Impact of the Nutritional Supplementation with DHA on Cystic Fibrosis Microbiota

Abstract

Cystic fibrosis (CF) is a genetic disease characterized by the formation of thick secretions in the gut and airways, among other anatomical locations, which leads to an altered microbiota. Understanding the significance of bacterial species that colonize and persist in CF patients requires a detailed examination of bacterial community structures. In addition, deficiency in fatty acids, such as docosahexaenoic acid (DHA), is a common co-morbidity in CF patients who are malnourished. Thus, the restoration of DHA levels may have influence in the bacterial composition of CF microbiota. The aims of this study were, first, to analyze the gut and airway microbiota of CF patients using next generation sequencing (NGS) tools, secondly, to determine the DHA supplementation impact in the microbiota of both ecosystems, and finally, to associate particular bacterial profiles to different clinical variables as nutritional status and lung function. Forty-eight CF patients were randomized into two groups and receiving either DHA supplemented diet or placebo for 6 months. Fecal or sputum samples were collected before and after finishing the DHA or placebo supplementation (two samples per each patient). We performed V3-V4 16S rDNA NGS analysis to characterize the gut and lung microbiota at basal status in these patients. The results showed that gut and airways CF microbiota was aberrant, with significant inter-individual variability in their community structure. The core CF-gut microbiota consisted of Lachnospiraceae family and Streptococcus and Blautia genera. Airways in children were dominated by Streptococcus and Haemophilus whereas in adults Streptococcus was the only genera over 10% abundance. Lachnospiraceae abundance in CF-gut and children airways was linked to the effect of DHA supplementation in the bacterial composition. Only considering the top-28 most abundant genera in adult CF-airways, we were able to detect an association between strict anaerobes, such as Prevotella, Veillonella and Lachnospiraceae, and CF patients with lower lung function.