What is the skin microbiome?
The trillions of bacteria, fungi and viruses that live on the skin all over our bodies is part of the microbiome. JAX Associate Professor Julia Oh studies the human microbiome for its potential to deliver treatments for infectious and other diseases.
The human body is covered in microbes of many varieties: bacteria, virus, fungi and Archaea. And if you had to pick a part of your skin most prone to environmental changes, you might pick the palms of your hands. Your hands are constantly touching new, microbe-covered surfaces — think doorknobs, handrails and food — and they are probably the part of your body you wash with soap most frequently. Eating with your hands and opening doors might introduce new members to your community, while washing your hands might decrease the number of microbes and open up space for new members to fill.
Yet, according to Assistant Professor Julia Oh, Ph.D., despite these near-constant assaults, the microbial community on your hands is remarkably stable. In a recent paper in Cell, describing work she did while at the National Institutes of Health, Oh and colleagues used metagenomic shotgun sequencing to monitor changes to the skin community at various body sites for a short (one to two months) and long time period (one to two years) on the same person. Even after two years, the community on an individual’s hands remained very stable. This suggests that environmental factors like constant touching and washing are relatively insignificant to the acquisition of new bacteria on the skin. Moreover, this suggests that our microbial partners are in it for the long haul — or at least for two years.
The skin community does change pretty remarkably during the transition from childhood to adulthood. The change is likely due to the increase in sebum (oil) on the skin during and after puberty. Oh and colleagues discovered this transition in prior research published in Genome Medicine in 2012. However, this new evidence implies that once the environment of the skin is stable, so too are the microbes that live on it.
As an interesting side point, other researchers have determined that the palm microbiomes of cohabitating couples are more similar to each other’s than to those of other healthy adults (eLife, 2013). Thus, the skin microbiome is not completely free of influence from the outside world, and the influence of cohabitation on the microbiome of mice is well documented. In the future, it would be interesting to monitor the pre- and post- effects of cohabitation with a limited life cycle — say, between college roommates — and whether the effect is long-lasting after the roommates have separated.