[A morphological study of interactions of Candida albicans and Streptococcus mutans]

Denture stomatitis is caused mainly by infection of Candida albicans and Streptococcus mutans, the most predominant members of the bacterial flora on denture surfaces. The purpose of this study was to investigate the adhesion in vitro of C. albicans and of S. mutans to acrylic surfaces and their interactions. Concentrations of C. albicans and of S. mutans (mutational phase I and III in which activities of glucosyltransferases are higher and lower respectively) were of high levels (> or = 5.0 x 107 colony-forming-units per ml; CFU/ml). The colonies in brain-heart-infusion (BHI) broth added 5% sucrose incubated at 37 degrees C for 18 and 72 hours. Then the samples were dried and evaporated, and examined by S-700 and S-4100 SEM (HITACHI). It was found that S. mutans (mutational phase I) synthesized water-insoluble glucans concomitantly with the adhesion of both S. mutans and C. albicans to the acrylic surfaces. Also, adhesion of C. albicans, mediated by cell-to-cell interactions with S. mutans (especially mutational phase III), to the surfaces was observed.