Eczema: microbiome affects skin barrier

Bacteria community affects genes for healthy skin

Staphylococcus aureus bacteria dominate the microbial community on the skin of people with atopic dermatitis. © CDC
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Bacterial offenders? Researchers have found that in atopic dermatitis an unusually high number of staphylococci abound on the skin. These bacteria seem to displace other types of microbes and thus play an essential role in the pathological inflammatory processes. For depending on the composition of the bacterial community on the skin, apparently the activity of genes that are important for an intact and stable skin barrier changes.

The skin of eczema patients is often dry, red and itchy: the protective function of this important outer barrier of the body is disturbed by the disease in them. Even the smallest stimulus can therefore cause unpleasant inflammatory reactions. Bacteria play an important role here: "Recent studies show that the bacterial composition of the skin has an influence on the inflammatory process, " reports Matthias Reiger of the Technical University of Munich.

To further investigate this phenomenon, the microbiologist and his colleagues have now analyzed skin samples from healthy people and subjects with atopic dermatitis. How would the composition of the skin microbiome differ between these two groups? The evaluation revealed that noticeably many staphylococci were on the skin of neurodermatitis.

Atopic dermatitis in a toddler © Bernd Untiedt / CC-by-sa 3.0

Staphylococci dominate

Bacteria of this genus therefore clearly dominated the microbial community of the diseased skin. Often, Staphylococcus aureus was a sadly infamous hospital strain, regardless of whether the affected skin was acutely inflamed or not. "For certain inflamed samples, S. aureus consumed as much as 99 percent of the total microbial composition, " says Reiger.

As the scientists observed, the germ seems to displace other types of staphylococci: the more S. aureus bacteria are found on the skin, the less likely other species can be detected. But what mechanisms could be used to influence the condition of the skin? display

Altered gene activity

Further investigations showed that, depending on the respective bacterial inhabitants, the activity of some genes in the skin cells changed significantly. "This effect was particularly pronounced for four genes involved in the maintenance of an intact and stable skin barrier, " reports Reiger's colleague Avidan Neumann.

The microbiome therefore seems to be able to directly influence the skin barrier - and thus to be a decisive factor in the manifestation of atopic dermatitis and possibly also other skin diseases. The scientists want to explore the now discovered context in future studies in more detail. They also hope for new approaches to the treatment of chronic skin ailments. (Journal of Allergy and Clinical Immunology, 2018; doi: 10.1016 / j.jaci.2018.07.005)

(TU Munich, 13.08.2018 - DAL)