Methods: Children with eczema at 2 years old (n=26) and their matched (for gender, mode of delivery and feeding in first 6 months) healthy controls (n=26) were selected from the placebo group of a cohort of at-risk infants participating in an randomized double-blind placebo controlled trial on the protective effects of supplemental probiotics (first 6 months) on eczema and allergies. Children with eczema were subclassified into atopic eczema (n=12) and non-atopic eczema (n=14). Molecular evaluation of fecal microbiota were conducted using Fluorescence In Situ Hybridization-Flow Cytometry (FISH-FC) for fecal samples collected at 3 days, 1, 3, and 12 months. Probes were selected to target Eubacterium rectale-Clostridium coccoides group (Erec482), Clostridium leptum subgroup (Clep866 and the corresponding competitor probes), Bacteroides-Prevotella group (Bac303), Bifidobacterium genus (Bif164), Atopobium group (Ato291), Lactobacilli- Enterococci group (Lab158), Enterobacteriaceae family (Enter1432) and Clostridium perfringens (Cperf191). Linear mixed model was used to evaluate the longitudinal differences (i.e. 4 time points) of bacterial targets while adjusting for gender, mode of delivery, feeding up to 6 months, and allergic rhinitis and wheezing within the eczema group at 2 years of age.
Results: Longitudinal analyses over four time points showed that higher relative abundance of Enterobacteriaceae [coefficient (B): 1.104, 95% confidence interval (CI):0.175-2.033, adj p=0.022] in children with eczema by 2 years of age. Similar observations were made when eczema group was subanalyzed into non-atopic and atopic eczema, where higher relative abundance of Enterobacteriaceae [B:1.357, 95%CI; 0.382-2.332, adj p=0.008] and [B:1.165, 95%CI; 0.221-2.109, adj p=0.019] were observed respectively as compared to healthy controls. Relative abundance of Clostridium perfringenswere also higher when subanalyzed for non-atopic [B:0.572, 95%CI; 0.0009-1.144, adj p=0.050] and atopic eczema [B:0.000451, 95%CI: 0.0001-0.0007, adj p=0.012] compared to healthy controls.
Conclusions: Our data suggests that relative abundance of selective microbial targets particularly Enterbacteriaceaea and Clostridium perfringens in the fecal microbiota of infants influence the development of eczema in early childhood.