Infants with low levels of beneficial gut bacteria at risk for atopic eczema
MedWire News: Infants with low levels of beneficial bacteria in the gut during the first month of life are more likely to develop atopic eczema than those with normal levels, show study findings.
"The results support the hypothesis that low microbial diversity early in life is associated with an increased risk for allergic disease," say Thomas Abrahamsson (Linköping University Hospital, Sweden) and co-authors.
To assess bacterial gut levels in stool samples from 20 infants with IgE-associated eczema and 20 infants without any allergic disease at 2 years of age, the team analyzed the type of bacteria and their levels using a novel method of gene sequencing at 1 week, 1 month, and 12 months of age.
Infants with IgE-associated eczema were found to have a significantly lower bacterial diversity at 1 month compared with infants who did not develop allergic disease. These children were also found to have significantly lower level of the Bacteriodetes bacterial type.
In addition, bacterial diversity of the Proteobacteria bacterial type, which comprises gram-negative bacteria, was also reduced in children with atopic eczema at 12 months of age.
The authors say that lack of endotoxin associated with low levels of Proteobacteria has been associated with an increased risk for atopic eczema, and may therefore explain the finding of atopic eczema in infants with low levels of Proteobacteria.
"It is noteworthy that the most important difference appeared in the first months of life, supporting the theory that factors influencing the early maturation of the immune system might be especially important for subsequent allergy development," say the researchers.
Despite the study findings, the authors say the study did not clarify the debate over whether a low total diversity of gut bacteria in early childhood is more important that the altered prevalence of particular bacterial species in allergy development.
"Total diversity was important, but the differences in diversity and relative abundance seemed to be defined to specific bacteria," comment Abrahamsson and team.
Finally, the authors note that previously associated bacteria with allergic disease such as bifidobacteria and clostridia did not show an association in the current study.
"The results support the hypothesis that low microbial diversity in early life is associated with an increased risk for allergic disease," conclude the authors in the Journal of Allergy and Clinical Immunology.
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By Ingrid Grasmo