ABSTRACT

Objective: The aim of this study was to evaluate the relationship between sucrose concentration and bacteria proportion in a multispecies biofilm model. Methods: Streptococcus mutans (S. mutans), Streptococcus oralis (S. oralis), and Actinomyces naeslundii (A. naeslundii) were chose to form a multispecies biofilm. Different concentration (0–40%) of sucrose was introduced to the multispecies biofilm 3 times per day (30 min per time). And then the bacteria proportion and acid production of the biofilms were analyzed. Results: Increasing sucrose level increased CFU count of S. mutans up to a certain concentration (5% sucrose), after which the number of S. mutans slightly decreased, but the CFU counts of S. oralis and A. naeslundii continually decreased with sucrose concentration increase, especially, from 5% sucrose, the reduction was significant, and S. mutans became the dominant species in the biofilms. Furthermore, the acid production ability of the multispecies biofilm gradually increased and slightly decreased with sucrose concentration increased, and the turning concentration was 5%. Conclusion: Our findings suggest that increasing sucrose level could increase the competitiveness of S. mutans in the multispecies biofilm, which may shift the biofilm to a more cariogenic one, and 5% sucrose formed a most cariogenic biofilm in this study.

摘要

目的：本研究旨在评估多物种生物膜模型中蔗糖浓度与细菌比例之间的关系。方法：选择变形链球菌（S. mutans），口腔链球菌（S. oralis）和内生放线菌（A. na es undis）形成多物种生物膜。每天3次（每次30分钟）将不同浓度（0–40％）的蔗糖引入多物种生物膜。然后分析了生物膜的细菌比例和产酸量。结果：增加蔗糖水平增加了变形链球菌的CFU计数达到一定的浓度（5％蔗糖），的数量之后，变形链球菌略有下降，但的CFU计数口腔链球菌和A. NA ES lundii不断用蔗糖浓度增加而降低，尤其是，从5％蔗糖，减少是显着的，变形链球菌成为生物膜中的优势种。此外，随着蔗糖浓度的增加，多种生物膜的产酸能力逐渐提高，并略有下降，转向浓度为5％。结论：我们的研究结果表明，增加蔗糖水平可以提高变形链球菌的竞争力。 在多物种生物膜中，可能使生物膜转变为更具致龋性的生物膜，而在这项研究中，5％的蔗糖形成了最具致癌性的生物膜。