Study Finds 90% of Viruses on Skin Unclassified

A new study, published in mBio revealed that 90% of viruses found on skin have never been described before.
The study, conducted by the Perelman School of Medicine at the University of Pennsylvania, analyzed skin samples from 16 healthy individuals. The analysis found the most abundant virus found was the human papilloma virus, no surprise to researchers. However they were surprised when 90 percent of DNA from the skin samples did not match viral genes in the existing database.
Elizabeth A. Grice, PhD , senior author of the study and assistant professor of Dermatology at Penn Medicine said, “”More than 90 percent was what we call viral dark matter — it had features of viral genetic material but no taxonomic classification.”
The microbes living on our skin have a major influence on health and disease, as beneficial microbes fight off infection and maintain skin integrity and healing, while harmful microbes can penetrate the skin and invade the body.
Dr. Grice said, “There has been a real need for a better understanding of these viruses, given their potential effects on our skin cells as well as on our resident bacteria,” she continued, “Until now, relatively little work has been done in this area, in part because of the technical challenges involved. For example, a skin swab taken for analysis will contain mostly human and bacterial DNA, and only a tiny amount of viral genetic material — the proverbial needles in the haystack.”
The researchers used new techniques to isolate the virus-like particles (VLPs) from the samples and analyze the DNA without relying on the database of previously sampled viruses.
The study also found a common link in many of the viral DNA from the studies, showing they belonged to a class of viruses called phage virus. Phage viruses are known to reside within bacteria. When the skin bacteria of all 16 subjects was sequenced, researchers found evidence of prior invasion by the same phage viruses.
The study concluded that the viruses present on the skin were resident in the bacteria on the skin, and in addition the phage viruses made the “host” bacteria more resistant to antibiotics, allowing for skin infection.
Interestingly, the study took samples from various parts of the body, forehead, navel, armpit and other areas, and found the most diverse viruses were found in the crook of the arm.
Grice and her team are using the results of the study and consequent sequencing of the viruses to study them and have made the supplemental information available to other researchers for future studies and comparison.