Dietary Habits and Atopic Dermatitis Significantly Influence the Fecal Microbiome.

BACKGROUND

Atopic dermatitis (AD) has been associated with microbial gut dysbiosis in children. Data in adults is scarce.

OBJECTIVE

We sought to explore the fecal microbiome composition in AD patients versus healthy controls (HC) and investigate the impact of environmental aspects such as the geographical location and dietary habits.

METHODS

In this case control study, a total of 140 fecal samples from 69 AD patients and 71 HC from Tanzania (TZ) and Switzerland (CH) were analyzed. Illumina shotgun metagenomics sequencing was performed followed by taxonomic profiling, calculation of alpha/beta diversity, and permutational multivariate analysis of variance. Differentially abundant species and genera between AD and HC were evaluated.

RESULTS

Alpha diversity (Shannon Index) did not significantly differ between AD and HC. The presence of AD was identified as a significant source of fecal microbiome variation (Bray-Curtis beta diversity). On the species level, Faecalibacterium taiwanense was more abundant in AD, and Vescimonas sp000435555 in HC. On the genus level, CAG-302 (NCBI: Clostridium) was more abundant in HC. Geographical location was associated with distinct dietary habits. Prevotella was significantly more abundant in TZ, whereas Alistipes and Bacteroides were significantly more abundant in CH.

CONCLUSIONS

The presence of AD significantly impacted the fecal microbiome variation and was associated with a particular microbial composition. The impact of geographical location on the fecal microbiome may be related to nutritional differences. Our data support the rationale of a gut-skin axis and pave the way towards therapeutic approaches modulating the microbiome.