Children with eczema have distinct gut microbiome

By Helen Albert, Senior medwireNews Reporter

Infants with eczema have more diverse total gut microbiota than those without the skin condition, show study findings.

Notably, the types of bacteria observed in children with eczema were more similar to those of adults than of healthy children the same age.

Based on previous observations of a link between the composition of intestinal microbiota and atopic disease, Lotta Nylund (University of Turku, Finland) and colleagues tested fecal samples taken from 15 children with eczema and 19 healthy controls at 6 and 18 months of age, to evaluate their microbial composition.

As reported in BMC Microbiology, the fecal microbiota of the samples did not differ at 6 months of age, but significant between-group differences were apparent by the age of 18 months. At 18 months of age children with eczema had a significantly increased profusion of five groups of bacteria in the Clostridium clusters IV and XIVa compared with healthy control children. They also had a threefold reduction in Bacteroidetes phylum bacteria (seven groups) relative to control children.

The team suggests that low levels of immunoglobulin A in the digestive system of children with eczema could "permit establishment of a wider variety of bacteria and explain the higher bacterial diversity in children with eczema."

Alternatively, decreased levels or an altered repertoire of antimicrobial peptides secreted into the gut lumen could account for the increased microbial diversity.

Overall, microbial diversity increased over time in both groups, from a mean of 78 on the Simpson's Diversity Index at 6 months to 111 at 18 months. In addition, as might be expected from a reduction in milk intake, the frequency of bifidobacteria decreased between the age of 6 and 18 months from 22.9% to 12.6%.

"The composition of bacteria in a child's gut depends on its environment and the food it eats. You would expect that as a child's diet changes so will the bacteria present," commented Nylund in a press statement.

"The number of bifidobacteria naturally falls with age and in total we found 21 groups of bacteria which changed in this time period. However, it is the early change towards adult-type bacteria which seems to be a risk factor for eczema."

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