About 200 different types of fungi live on the feet. According to a group of experts from the National Institutes of Health (NIH), although these microorganisms spread throughout the body, to stay to ‘live’, they have their preferences. Specifically on the feet, where they like to hide the most is on the heel, on the nails and between the toes.
Since Hippocrates first described oral thrush in 400 BC, scientists have continued to explore and investigate the role that fungi and microbial communities play in human health and disease. It has been shown that “bacterial diversity can be predicted based on whether the skin is moist, dry or oily, however, the richness of the fungi depends on the site of the body,” explains Heidi Kong, one of the main authors of the research, published in the ‘Nature’ magazine. Since “mushrooms can be slow and difficult to grow in the lab,” he added, “a very accurate map of these microorganisms in the body had not been drawn.”
To this end, researchers from the National Human Genome Research Institute and the National Cancer Institute, both of nih, sequenced the DNA of genes living on the skin of 14 different areas of the body (samples were taken from the toe nails, behind the ear, the nostril, ear canal, chest, elbow, etc.) 10 healthy adults.
The site of the body with the greatest diversity of fungi is the foot: in the heel inhabit about 80 types, in the nails about 60 and in the skin between the toes about 40. Behind is the palm of the hand and forearm, where between 18 and 32 different classes coexist. However, in the head, the back, the back of the neck, the inside and behind the ears and in the broom, a much smaller variety was found, between two and 10 types.
The most common genus: ‘Malassezia’, which was located in 11 of the 14 areas analyzed, including the head, nose, behind the ears and heels, where they cohabit with other types of fungi such as ‘Aspergillus’ or ‘Cryptococcus’.
As NHGRI’s Chief Scientific Officer Daniel Kastner points out, “this data completes our knowledge of the human microbiome,” made up of fungi, bacteria and viruses. The authors had already conducted an earlier study with sequencing of the skin bacteria genome.
A skin breakthrough
In the same sense, Heidi Kong points out that “by getting a more complete picture of fungal and bacterial ecosystems, we will be able to better treat skin diseases by fungi”, such as seborrheic, atopic dermatitis or athlete’s foot.
In this study, researchers observed that 20% of participants had heel and fingertip problems and nail changes that might be related to fungal infections. In fact, in these cases, the fungal population in the affected areas was larger. “The fungi that live in the body are harmless, but they cause infections when they multiply,” the study’s researchers clarify.
Considering that “our study has focused on areas of the skin where we often find diseases associated with fungi,” says Dr. Kong, this new map could help the development of new research on skin diseases and new medicines, as current antifungals carry side effects such as liver damage.
