The researchers studied 21 infants who already had evidence of atopic eczema, and were at heightened risk for chronic allergic disease.
When the babies were weaned onto hydrolyzed whey formula feed, 8 of them reacted adversely to it.
Among the remaining 13, 7 were fed the formula supplemented with probiotic bacteria - Bifidobacterium lactis - and 6 were fed unsupplemented formula.
Stool samples were taken from the 8 highly reactive babies before weaning, while the rest of the babies provided stool samples before and after weaning.
|"Unfriendly" bacteria may be implicated in development of allergic response.
The 8 highly reactive babies had greater numbers of "unfriendly" bacteria in their stool samples than the 13 babies who did not react to the formula feed.
However, to gauge the allergic response in all the babies, IgE levels were measured.
These directly corresponded to the levels of Escherichia coli, bacteria that can cause infection in this age group, and the numbers of bacteroides species in the highly reactive babies.
Although the finding has yet to be verified, the authors suggest that these organisms are implicated in the development of an allergic response, possibly by causing changes in the gut ecosystem.
Supplementation of formula feed with probiotic bacteria significantly reduced the numbers of E. coli bacteria and prevented an increase in the numbers of bacteroides during weaning.
Probiotic supplementation, say the authors, might help alleviate the allergic response in babies during weaning.