Purpose: Evidence on the role of the gut microbiota in atopic dermatitis is inconsistent as human intestinal microbiota is influenced by geography. This cross-sectional study therefore aimed to compare differences in the gut microbiota of infants with atopic dermatitis and healthy infants in Guangzhou, China, by analyzing their stool.
Patients and Methods: The composition of the intestinal microbiota was analyzed from the stool samples of 20 infants with atopic dermatitis (AD group) and 25 healthy infants (non-AD group) (1– 6 months old), using full-length 16S rRNA gene sequencing. The Wilcoxon test was used to analyze the relative abundance of bacteria by phylum, family, genus, and species between groups; microbial community richness and diversity were compared between the two groups.
Results: There were no significant differences in the microbial community richness and diversity between the two groups. At the phylum level, 11 bacterial phyla were found; most sequences belonged to one of the three dominant bacterial phyla – Firmicutes, Proteobacteria, and Bacteroidetes. The top 10 microbes at the phylum, family, and genus levels showed no significant changes in their composition within the gut microbiota between the AD and non-AD groups. A decrease in the ratio of the Streptococcus  genus was found in atopic dermatitis group when compared with healthy controls (p=0.048).
Conclusion: A decrease in the abundance of Streptococcus  was found in children with AD. The role of Streptococcus in the development of AD needs to be confirmed in a large cohort study.
Keywords: allergy, infant, gut microbiome, Streptococcus