Alteration of the coadherence of Candida albicans with oral bacteria by dietary sugars

Interactions between bacterial oral flora and Candida albicans are importan t in denture plaque formation. This study therefore first aimed to quantify the coadherence of C. albicans and bacteria by the use of a bioluminescent adenosine triphosphate (ATP) assay based on the firefly luciferase-lucifer in system. The second aim was to examine the effect of i) dietary sugars (u sed for preculture) and ii) enzymatic digestion of fungi on the coadherence . When yeast was preincubated in yeast nitrogen base medium (YNB) supplemen ted with 250 MM glucose, the yeast coadhered with all isolates of Streptocc us mutans and Streptococcus sanguis, and no significant coadhesion was obse rved with the isolates of Streptococcus sobrinus, Streptococcus salivarius, Lactobacillus and Actinomyces. However, when the yeast was precultured in YNB supplemented with 500 mM galactose, the yeast coadhered with S. salivar ius and Actinomyces, which was not observed when the yeast was grown in YNB with glucose. In addition, the coadherence of the yeast with the isolates of S. sanguis was significantly reduced. Enzymatic digestion of yeast and a reverse transcription polymerase chain reaction assay revealed that expres sion of at least two types of proteinaceous adhesins. are involved in these phenomena.