Adhesion of Staphylococcus aureus to human skin is exceptionally strong

Staphylococcus aureus is a bacterial pathogen that colonizes the skin and the nose of humans, and which can cause various diseases, such as eczema (atopic dermatitis). This microbe has become resistant to multiple antibiotics, meaning there is an urgent need to fully understand the molecular mechanisms leading to host colonization and infection, and to find alternative antibacterial therapies. In collaboration with the Trinity College Dublin, a UCLouvain team has discovered that S. aureus uses a special surface protein, FnBPB, to specifically bind to the human skin surface protein loricrin. Using nanotechniques, they found that the bond formed between FnBPB and loricrin is exceptionally strong, much stronger than the vast majority of other biomolecular bonds. Remarkably, the bond strength increases dramatically when subjected to physical stress, as occurring when we wash ourselves or during skin epidermidis turnover, pointing to an unusual "catch bond" adhesion and colonization mechanism. Under mechanical tension, biological complexes typically slip apart easily ("slip bonds"), whereas "catch bonds" counterintuitively become stronger. The FnBPB-loricrin interaction, reported in Nature Communications, provides S. aureus with a means to firmly attach to the epidermidis under physiological shear stress, increasing its ability to colonize the human skin and cause infection. This mechanism represents a promising target for anti-adhesion therapy, i.e. the design of inhibitors capable to efficiently prevent staphylococcal-skin interactions. The study was funded by an ERC advanced grant aiming at using nanotechnology to understand and overcome the adhesion of S. aureus to biomaterials and host tissues ( https://futurumcareers.com/using-nanotechnology-to-overcome-the-adhesion-of-the-bacterial-pathogen-staphylococcus-aureus).