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 ...»»»»
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.^^^^
