Perturbations of the gut microbiome in infants with atopic dermatitis

Background: Perturbations of the developing gut microbiota in infancy can shape the development of the immune system and are linked to the risk of allergic diseases. Objective: To understand the role of the gut microbiome in the development of atopic dermatitis, the metagenome of the gut microbiome in infancy was analyzed. Methods: The gut microbiota was analyzed in fecal samples from 129 infants (6-month-old), including 66 healthy infants and 63 infants with atopic dermatitis. The composition and functional profile of the gut microbiome were analyzed by pyrosequencing based on the 16S rRNA gene and whole metagenome sequencing. In addition, the total number of bacteria in the feces was determined by real-time PCR. Results: Two gut microbiota groups, Bifidobacterium dominated group and Escherichia/Veillonella dominated group, were found in 6-month-old infants. The bacterial cell amounts in the feces was lower in infants with AD than in controls. Although no specific taxa directly correlated with the presence of AD, whole metagenome analysis revealed differences in functional genes related to immune development. Diverse microbes and mucin-degrading bacteria (Akkermansia muciniphila, Ruminocccus gnavus, and Lachnospiraceae bacterium 2_1_58FAA) were associated with genes related to oxidative phosphorylation, PI3K-Akt signaling, estrogen signaling, NOD-like receptor signaling, and antigen processing and presentation in the control group compared to the AD group (P < 0.05). Conclusions: Alterations in the gut microbiome may be associated with the development of atopic dermatitis due to different bacterial genes that can modulate host immune cell function.