Reduced gut microbial diversity in early life is associated with later development of eczema but not atopy in high‐risk infants

Background: Alterations in intestinal microflora have been linked to the development of allergic disease. Recent studies suggest that healthy infant immune development may depend on the establishment of a diverse gut microbiota rather than the presence or absence of specific microbial strains. Objectives: We investigated the relationship between diversity of gut microbiota in the early postnatal period and subsequent development of eczema and atopy in the first year of life. Methods: Fecal samples were collected 1 wk after birth from 98 infants at high risk of allergic disease, who were followed prospectively to age 12 months. Fecal microbial diversity was assessed by terminal restriction fragment length polymorphism (T‐RFLP) using restriction enzymes Sau96I and AluI, with a greater number of peaks representing greater diversity of bacterial communities. Results: Microbial diversity at day 7 was significantly lower in infants with eczema at age 12 months as compared to infants without eczema (AluI mean number of peaks 13.1 vs. 15.5, p = 0.003, 95% CI for difference in means ?3.9, ?0.8; Sau96I 14.7 vs. 17.2, p = 0.03, 95% CI ?4.9, ?0.3). No differences were observed for atopic compared to non‐atopic infants, or infants with two allergic parents compared to those with one or no allergic parent. Conclusions: A more diverse intestinal microbiota in the first week of life is associated with a reduced risk of subsequent eczema in infants at increased risk of allergic disease. Interventions that enhance microbial diversity in early life may provide an effective means for the prevention of eczema in high‐risk infants.