362 Natural sulfated polysaccharides inhibit the adhesion of Staphylococcus aureus to the stratum corneum

In atopic dermatitis (AD) Staphylococcus aureus adheres to corneodesmosin present on corneocyte villus protrusions in the stratum corneum (SC). This adhesion is mediated through its adhesins clumping factor B (ClfB) and fibronectin binding protein B. The overpopulation of S. aureus on AD lesions exacerbates underlying inflammatory condition and itch. Thus, it is desirable to inhibit the adhesion of S. aureus to the SC to provide therapeutic improvement of AD. The objective of this study was to evaluate natural sulfated polysaccharides in vitro adhesion assays for their potential to inhibit the adhesion of S. aureus to the SC of human skin. In a microplate bacterial adhesion assay the sulfated polysaccharide carrageenan extracted from the red seaweed Chondrus crispus and the fucoidan extracted from the brown seaweed Fucus vesiculosus significantly inhibited in a dose dependent manner the binding of the ClfB expressing S. aureus 25904 in exponential phase to fibrinogen – a well described target of S. aureus. Equally both these polysaccharides inhibited in vitro the adhesion of S. aureus 25904 to the SC sampled either by D-squams or Blenderm tape. Confocal analysis showed that S. aureus preferentially bound to the periphery of corneocytes and both carrageenan and fucoidan strongly inhibited this binding. In a corneocyte binding assay both polysaccharides significantly inhibited in a dose dependent manner the adhesion of the AD

S. aureus strain CC1 to corneocytes. In a reconstructed epidermal model pretreatment with these polysaccharides reduced the binding of S. aureus CC1 by 1 log cfu/ml. Taken together the data showed that natural sulfated polysaccharides have the potential to inhibit the adhesion of S. aureus and thus could be used to treat the symptoms of inflammation and itch associated with AD.