The diversity of the skin microbial world is displayed on the Tree of Life, highlighting the use of metagenomic sequencing to study the biogeography and stability of the skin microbiome. Credit: Alan Hoofring, National Institutes of Health.

Although most of us wash regularly we cannot get rid of our own flora of skin bacteria new study shows. Our microbiome remains the same despite external influences.

There is a great variety of different bacteria on our skin and most of them are harmless and actually beneficial to us. A few of are however associated with diseases such as psoriasis.

A new U.S. study shows that our flora of skin bacteria is not influenced by contact with other people, clothing or the surrounding area, nor is it affected by showers and constant washing. The microbiome is thus a kind of microbial fingerprint as the bacteria of every individual remain, well, individual.

The researchers examined twelve healthy people with and their respective microbiome of bacteria for two years. They took samples from 17 different places on their bodies. It turned out that oily places such as the back and external auditory canal contained the most stable bacterial and fungal communities, and even highly exposed, dry sites such as the palm showed remarkable stability over time. By contrast, places with high microbial diversity, such as the feet and moist sites, were the least stable over time, perhaps due to factors such as personal hygiene or exposure to more variable environments.

The study also indicates that contact with other objects and surfaces do not affect our skin bacteria much at all. This knowledge may perhaps make people less afraid of touching objects in public places, such as holding straps in the public transport, the bus or the grab bars in the subway.

Temporal Stability of the Human Skin Microbiome