THE EFFECTS OF HEXETIDINE (ORALDENE(TM)) ON THE ADHERENCE OF CANDIDA-ALBICANS TO HUMAN BUCCAL EPITHELIAL-CELLS IN-VITRO AND EX-VIVO AND ON IN-VITRO MORPHOGENESIS

Purpose. This study reports the effects of hexetidine (Oraldene(TM)) o n two virulence attributes of Candida albicans, namely, in vitro and e x vivo adherence of yeast cells to buccal epithelial cells (BEG) and i n vitro morphogenesis. Methods. The effects of hexetidine treatment of either yeast cells (stationary and exponential phases) or BEC on Cand idal adherence, in terms of viable and non-viable adherent yeast cells , were evaluated using an acridine orange stain in conjunction with fl uorescence microscopy. Ex vivo anti-adherence effects were determined by rinsing BEC in vivo with hexetidine (0.1%), removal of BEC after de fined periods and inclusion in the adherence assay. The effects of hex etidine on morphogenesis were evaluated using light microscopy. Yeast cell viability following exposure to a range of concentration of hexet idine (0.005-0.1% v/v) for defined periods was determined following se rial dilution and enumeration on solid media. Results. Treatment of st ationary and exponential phase yeast cells or BEC with hexetidine (0.1 %) for a range of times (10-300 s) or, alternatively, with a range of concentrations of hexetidine (0.005-0.1%) for a fixed time (30s) signi ficantly decreased the resultant Candidal/epithelial adhesion. No corr elations were observed between reduced adherence and either time of tr eatment or hexetidine concentration. In vivo treatment of BEC with hex etidine (0.1%) for 30s resulted in prolonged and significant reduction s in the ex vivo adherence of both viable and non-viable yeast cells f or periods of up to (and including) four hours post-rinsing. Treatment of C. albicans blastospores with hexetidine (0.05, 0.1% v/v) for 10s and 30s totally inhibited Candida morphogenesis, whereas treatment wit h lower antiseptic concentrations significantly reduced the extent of Candida morphogenesis and the rate of hyphal development. The effects of hexetidine on yeast cell viability were both concentration and time -dependent. Conclusions. The reduced adherence of C. albicans to BEC a nd the modification or inhibition of morphogenesis following exposure to hexetidine suggests a clinical role for hexetidine in the prophylax is of both superficial candidosis and the systemic complications resul ting from invasion of sub-epithelial tissue.