Human skin reacts to environmental damage (chemicals, UV light) with an altered bacterial environment. A disturbed balance of bacterial species supports the development of skin diseases (acne, atopic dermatitis, eczema, skin rashes). Dry, itchy, sebum-containing, sebaceous or moisture-retaining skin correlates with a specific colonization and diversity of bacterial species.
From birth, people live with an individual skin microbiome, which grows and changes with us over the years. Different bacteria act as modulators of the immune system by triggering specific reactions and thus exerting a positive influence on the stability of the skin barrier. Commensal skin inhabitants influence the growth of pathogenic germs, inhibit their multiplication by means of antimicrobial molecules and proteases and can suppress a targeted T-cell inflammatory reaction.
A healthy skin microbiome comprises the bacterial groups staphylococci, corynebacteria, propionibacteria and enterococci. Staphylococcus epidermidis supports the integrity of the skin barrier through the production of sphingomyelinase and ceramides, one of the main lipid components of the skin. An impaired skin barrier and disturbed immune homeostasis causes an incorrect colonization, which is often associated with the growth of potential pathogenic germs. The spherical, gram-positive bacteriumStaphylococcus aureus are of particular importance. The proteolytic enzymes of this type cause the epidermis to become more permeable, allowing pathogenic organisms to penetrate deeper. In addition, bacterial metabolites and toxins promote the death of cells in the uppermost layer of the skin at the disturbed sites. This results in foci of infection and local dysbiosis with chronically delayed wound healing.
These findings form the basis for patient-specific therapeutic approaches aimed at reducing the colonization of harmful strains, strengthening resilience and increasing bacterial biodiversity. Prebiotics, probiotic bacterial strains, phages (bacteria-attacking viruses), antibiotics or buffer solutions can be used for this purpose. A microbiome analysis of the skin supports the diagnosis, the healing process and the subsequent follow-up after a therapeutic intervention.
