alters the bacterial microbiome of early oral biofilms.

The yeast is an oral commensal microorganism, occurring in the oral cavity of 50-70% of healthy individuals. Its effect on oral ecology has mostly been studied using dual-species models, which disregards the complex nature of oral biofilms. The aim of this study was to culture in a complex model to study its effect on oral biofilms. Biofilms, inoculated using pooled stimulated saliva with or without addition of , were grown under anaerobic, aerobic, or aerobic +5% CO conditions. Red autofluorescence was quantified using a spectrophotometer and visualized in fluorescence photographs. The microbiome of 5 h biofilms was determined using 16S rDNA sequencing. was only able to proliferate in biofilms grown under aerobic conditions. After 48 h, did not induce differences in total biofilm formation, lactic acid accumulation (cariogenic phenotype) or protease activity (periodontitis phenotype). , anaerobically grown biofilms developed red autofluorescence, irrespective of inoculum. However, under aerobic conditions, only -containing biofilms showed red autofluorescence. Facultative or strict anaerobic , and genera were significantly more abundant in biofilms with . Biofilms without contained more of the aerobic and facultative anaerobic genera , and . The presence of alters the bacterial microbiome in early oral biofilms, resulting in the presence of strictly anaerobic bacteria under oxygen-rich conditions. This study illustrates that should not be disregarded in healthy oral ecosystems, as it has the potential to influence bacteria significantly.