Our skin is a critical barrier, and it is made up of three layers; the outermost layer is the epidermis, below that sits the dermis, and the deepest layer is the subcutaneous tissue. The skin carries a community of microbes like other parts of our bodies. From person to person, the epidermis microbiome is unique. However, new work reported in mBio has shown that the bacteria in the dermis remain consistent across different genders and ages. This research, which used surgery patient skin samples from the hips and knees, may help us learn more about skin disorders like childhood eczema and psoriasis.
"We found that the microbiome in epidermis is unique. It is very different and depending on age and gender. On the other hand, the microbiome in dermis is the same - regardless of age and gender. This has not been shown before," said study co-author Lene Bay, a postdoctoral researcher at the Department of Immunology and Microbiology, University of Copenhagen.
"It is important that we drop the assumption that we are all different, and that the microbiome of the skin does not matter very much. We do know that bacteria play a major role in skin disorders. Therefore, we need to understand the bacteria and the skin in its three dimensions," said study co-author Thomas Bjarnsholt, Professor at the Department of Immunology and Microbiology, University of Copenhagen. "Especially in connection with skin disorders, you see that the healthy skin balance disappears and that there is a build-up of some dominant bacterial species. Hopefully, this knowledge will help us to understand for example how eczema occurs and which irregularities are taking place in the skin."
It's always possible that an infection will happen after surgery. This work may help us learn more about who is more likely to get those infections.
"It is not a huge problem, but there are many knee and hip operations on a yearly basis, and we will see more and more in the future. That is why it will represent a growing problem. We believe that the dermis' microbiome has a bearing on the risk of infection after surgery," added Bay. "When you cut through the skin during surgery, you may be pushing some of these bacteria even further down. And the underlying bacteria are not cleansed with surgical ethanol like the bacteria on epidermis. Which significance that may have and whether it may be the cause of post-surgery infections is one of the things that we need to study more closely."
The scientists want to analyze other areas of the skin next. Since the hips and knees can be dry, they are interested in studying oily and moist parts of the skin next. Eventually, they want to start assessing the skin microbiome of individuals with disease.