Humans are unique among mammals when it comes to the types and diversity of microorganisms that can be found on their skin. The human microbiome — the collection of microorganisms such as bacteria, fungi, and viruses that naturally occur on the skin — contains significantly less diversity than that of other mammals, according to a study published online ahead of print in Proceedings of the National Academy of Sciences (June 5, 2018). These differences could have implications for human health and immune systems.
“We were quite surprised when we saw just how distinct we humans are from almost all other mammals, at least in terms of the skin microbes that we can collect with a swab,” said senior author Josh Neufeld, PhD, biology professor at the University of Waterloo in Waterloo, Ont. in a press release.
The unique composition of microbial communities on the human skin may be affected by living in homes, regular bathing, and wearing clothing. Researchers claim that habitat is another important factor linked to the skin microbes on mammals.
“The first line that gets hit by modern hygienic practices is our skin,” said study co-author Ashley Ross, graduate student at the University of Waterloo. “Our skin is the largest organ of the body and the main barrier to the external environment.”
The human skin microbiome contains around 1,000 microorganisms such as
the bacteria called staphylococcus epidermidis (pictured above).
Photo by Janice Carr, courtesy of Wikimedia Commons.
The study also concluded that despite these important influences on mammalian skin microbial communities, microbial communities on mammalian skin may have changed over time with their hosts, a phenomenon called phylosymbiosis.
“We were able to measure phylosymbiosis between some of the mammalian classes and the corresponding communities on their skin,” said co-author Kirsten Müller, PhD, biology professor at the University of Waterloo. “It is exciting that we can still see this signal despite the contribution of habitat to the skin microbial community.”
The team of investigators, which also included Dr. J. Scott Weese, veterinary internist and pathobiology professor at Ontario Veterinary College at the University of Guelph in Guelph, Ont., plans to further examine whether co-evolution has taken place between skin microbial communities and their hosts, a mechanism that may account for their observations of phylosymbiosis.