Infant gut microbiota and the hygiene hypothesis of allergic disease

Background Inverse associations between allergic disease and having pets or siblings are commonly attributed to the hygiene hypothesis. As an extension, one could posit that a less diverse gut microbiome in the infant, also linked with the development of allergic disease, would be a function of fewer microbes in the home environment. Piglet studies, however, indicate that greater microbe diversity in the environment actually leads to reduced diversity of the gut microbiota. In this study, we characterize the infant gut microbiota in relation to environmental factors traditionally associated with the hygiene hypothesis.