The microbiome represents an interface that mediates interactions between the human body and the environment. The skin microbiome serves as the primary interface with the external environment and aids in host immune function by contributing as the first line of defense against pathogens. 

The objective of a recent study published in mSystems was to determine how the skin microbiome is first established or which environmental factors contribute to its development. 

This study compared the skin bacterial communities of 47 infants living in four populations in Mexico and the United States—spanning the socioeconomic gradient. The study entailed 16S rRNA bacterial gene sequencing on 119 samples (armpit, hand, and forehead).

The results revealed that infant skin bacterial diversity and composition are shaped by population-level factors, including those related to socioeconomic status and household composition, and vary by skin site and infant age. Differences in infant-environment interactions vary across the populations and influence infant microbial exposures, as well as the composition of infant skin bacterial communities. 

The findings suggested that variation in microbial exposures from the local environment in infancy can impact the establishment of the skin microbiome across body sites, with implications for developmental and health outcomes. 

Source: mSystems. 2020 Nov-Dec; 5(6): e00834-20. doi: 10.1128/mSystems.00834-20