HMO-metabolizing bacteria in the gut microbiome of infants with atopic dermatitis/eczema

Atopic dermatitis, commonly known as eczema, is an inflammatory skin condition that affects up to 20% of infants in the United States. The development of eczema in early life is predictive of other allergic diseases later in life in a process known as the atopic march. Like many inflammatory diseases, infants with eczema have an altered gut microbiome. A diet of breast milk is often associated with protection against eczema development. Human milk oligosaccharides (HMOs), the third most abundant component of breast milk, are of particular interest as they are indigestible by infants and act as a prebiotic to shape the gut microbiome. To understand the role of the gut microbiota in eczema development, it is important to know the differences in the HMO metabolizing capacity of the gut microbiota both at the species and gene level. Here, I use two geographically distinct infant cohorts from Michigan (MARCH) and Rhode Island (RESONANCE) to characterize some of these changes. I analyzed the diversity of the gut microbial communities from the two cohorts and found them to have similar alpha and beta diversity indices when comparing eczema and breastfeeding groups. Further, I show the strain level differences of target HMO metabolizing bacteria in the two cohorts. HMO metabolism is one of the ways the gut microbiota influences the development of an infant’s immune system. Therefore, understanding the differences in HMO metabolizing capacity in infants with eczema is important in halting the progression of the atopic march.