The bacterial pathogen Staphylococcus aureus has an essential role in atopic dermatitis (AD). Skin colonization of AD patients by S. aureus worsens the disease, yet the molecular determinants of the bacterium-skin adhesive interactions remain unclear. In particular, decreased natural moisturizing factor (NMF) levels in the stratum corneum are associated with more severe AD symptoms, but whether this is directly related to S. aureus adhesion remains debatable. 

A present study by Feuillie et al demonstrates a novel relationship between NMF expression in AD skin and the strength of bacterial adhesion. It explains that low-NMF corneocytes, unlike high-NMF ones, witness a thick layer coverage of nanoscale villus protrusions. S. aureus bacteria, isolated from AD skin, have been shown to bind much more vigorously to corneocytes when there is a reduced level of NMF. 

These strong binding forces may originate from a specific interaction between the bacterial adhesion clumping factor B (ClfB) and skin ligands. Notably, mechanical tension strengthens ClfB-mediated adhesion, similar to catch bonds, indicating that physical stress promotes colonization of AD skin by S. aureus. 

Collectively, these findings indicate that the patient′s NMF levels regulate the strength of S. aureus-corneocyte adhesion, the first step in skin colonization and that the ClfB binding mechanism could be a potential target for new therapeutic treatments.

Source: Feuillie C, Vitry P, McAleer MA, et al. Adhesion of Staphylococcus aureus to corneocytes from atopic dermatitis patients is controlled by natural moisturizing factor levels. mBio. 2018;9(4):e01184-18.