IADR Abstract Archives
Excess Sugar Modifies Biofilms of Candida Albicans and Streptococcus Sanguinis
Objectives: S. sanguinis is a commensal bacterium of the dental biofilm associated with caries-free teeth. The pathobiont yeast C. albicans is present in both oral health and caries. So far, it has not been described how both microorganisms coexist in biofilms under limiting and excess sugar conditions. Our aim was to determine the effect of excess and limiting concentration of sugar on the biological and chemical parameters of dual biofilms of an oral clinical isolate of C. albicans with S. sanguinis.
Methods: An in vitro caries model was used with slabs of bovine enamel as substrate for the development of biofilms. The slabs/biofilms were under an exposure regimen to 10% sucrose or 0.9% NaCl for 5min 3 times per day for 5 days (excess and limitation of sugar, respectively). Viable cells of each microorganism, hyphal quantification in C. albicans (biological parameters), biofilm pH and surface microhardness of enamel slabs (chemical parameters) were determined, and the biofilms were observed in SEM. t-test was used for variables except viability (Wilcoxon test) (p<0.05).
Results: Yeast viability was higher in sucrose than in NaCl (median: 2.95x106 and 1.67x106 CFU/mL respectively; p<0.0001). On the contrary, bacteria viability was higher in NaCl than in sucrose (median: 4.1x108 and 2.9x108 CFU/mL, respectively; p<0.0001). The number of hyphae developed by the yeast was higher in sucrose (p<0.05). The pH values in the course of time (approx. 142h) in NaCl condition remained around 6.35±0.09 versus values between 5.95 and 5.0 in sucrose (p<0.05). The percentage of loss of superficial microhardness was 60.4%±8.3 and 73.9%±10.7 (p<0.05) in the NaCl and sucrose condition, respectively.
Conclusions: Excess sugar modifies the biological and chemical parameters of dual biofilms of C. albicans and S. sanguinis. It seems that the bacterium prevents pronounced drops in pH in the sucrose condition and stimulates the development of hyphae in the yeast.
Methods: An in vitro caries model was used with slabs of bovine enamel as substrate for the development of biofilms. The slabs/biofilms were under an exposure regimen to 10% sucrose or 0.9% NaCl for 5min 3 times per day for 5 days (excess and limitation of sugar, respectively). Viable cells of each microorganism, hyphal quantification in C. albicans (biological parameters), biofilm pH and surface microhardness of enamel slabs (chemical parameters) were determined, and the biofilms were observed in SEM. t-test was used for variables except viability (Wilcoxon test) (p<0.05).
Results: Yeast viability was higher in sucrose than in NaCl (median: 2.95x106 and 1.67x106 CFU/mL respectively; p<0.0001). On the contrary, bacteria viability was higher in NaCl than in sucrose (median: 4.1x108 and 2.9x108 CFU/mL, respectively; p<0.0001). The number of hyphae developed by the yeast was higher in sucrose (p<0.05). The pH values in the course of time (approx. 142h) in NaCl condition remained around 6.35±0.09 versus values between 5.95 and 5.0 in sucrose (p<0.05). The percentage of loss of superficial microhardness was 60.4%±8.3 and 73.9%±10.7 (p<0.05) in the NaCl and sucrose condition, respectively.
Conclusions: Excess sugar modifies the biological and chemical parameters of dual biofilms of C. albicans and S. sanguinis. It seems that the bacterium prevents pronounced drops in pH in the sucrose condition and stimulates the development of hyphae in the yeast.