The effect of adherent oral streptococci on the subsequent adherence of Candida albicans to acrylic in vitro.

The adherence of Streptococcus sanguis and Streptococcus salivarius to acrylic was measured after 1 h incubation at 37°C. The percentage of a microscopic field covered by cells (percentage coverage), obtained using a computer-based image analysis system, was taken as an indication of cell adherence. Streptococcus sanguis gave higher percentage coverage than S. salivarius. The percentage coverage of both species decreased with decreasing concentration of cell suspension. Cells from a Candida albicans suspension adhered to these adherent streptococci after 1 h incubation at 37°C, in preference to the acrylic. A significant positive correlation was found between the percentage of a field covered by cells and the number of adherent yeasts per microscopic field. Increasing numbers of adherent streptococci appeared to provide more surfaces for C. albicans attachment