Lower airway microbiota in children with Down syndrome compared to controls with similar respiratory symptomatology.

Background: Children with Down syndrome (DS) often present with chronic or recurrent respiratory symptoms and generally have a more severe and prolonged disease course in case of infection. This can be caused by anatomical and/or immunological predisposition. With this study, we aim to compare microbial composition in the lower airways of patients with DS versus controls, to see if we can explain the difference in disease course.

Methods: All endoscopic procedures under general anesthesia in patients with DS were reviewed retrospectively. We compared the microbiological data from bronchoalveolar lavage fluid (BALF) cultures (when available) to a cohort of children with chronic respiratory symptoms but without any other relevant medical history.

Results: Endoscopic data were available for 65 DS patients, BAL cultures for 47 out of 65 patients (72%). The "control" group consisted of 150 children without significant underlying disease, who were matched for age and sex. BAL culture results were available for 135 out of 150 patients (90%). Microorganisms were categorized and compared between both groups, with no statistical differences. Among the microorganisms tested, the most frequently reported were typical bacteria such as Haemophilus influenzae, Moraxella catarrhalis, Streptococci and Staphylococci.

Conclusions: No significant differences in lower airways microbial composition of children with DS and chronic respiratory symptoms were found when compared to controls presenting similar symptomatology. A suggestion for future research may be to investigate possible differences in drug sensitivity.