[Molecular pathogenesis of oral candidiasis (candidosis)]

Candida species are the most important pathogenic fungi in the oral cavity with the predominance of Candida albicans. In this review the authors summarise the most important cell-surface bound pathogenical factors such as fibrinogen, fibronectin, thrombin, collagen, laminin and vitronectin-binding proteins and extracellular virulence enzymes of Candida albicans and some microbiological aspects of oral candidiasis (candidosis). Adherence to both artificial and mucosal surfaces is mediated by hydrophobic interactions and by ligand-receptor attachment. Surface bound proteins on Candida cells bind to mucosal surface proteins. Broad spectrum antibacterial treatment liberates binding sites for Candida colonisation by means of reducing the number of bacterial normal flora in the oral cavity. Non immune humoral factors such as iron, lysosyme, hystidine-rich-polypeptides, lactoferrin, lactoperoxidase and immune globulins such as s-IgA, moreover, elements of cellular immunity, especially polymorphonuclear leucocytes contribute to preventing the establishment of Candida infection. A disbalance in these constituents may result in colonisation and biofilm production of Candida. The biofilm consist of serum proteins mainly fibrin, desquamated epithelial cells, dead leukocytes, living and multiplying candida cells, pseudohyphae and extracellular matrix excreted by candida cells. Living candida cells are deeply embedded in the biofilm, thus protected from defence mechanisms of the host. Continuous destruction of mucosal surfaces beneath the biofilm may create a portal of entry for systematic candidal infections.