Qiu Yuan-Xin, Mao Meng-Ying, Jiang Dan, Hong Xiao, Yang Ying-Ming, Hu Tao
Department of Preventive Dentistry, State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan, China.
Department of Operative Dentistry and Endodontics, State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan, China.
J Dent Sci. 2016 Mar;11(1):41-47. doi: 10.1016/j.jds.2015.08.001. Epub 2015 Nov 21.
BACKGROUND/PURPOSE: The co-operative effect of exogenous dextranase (Dex) and sodium fluoride (NaF) on monospecies biofilms is impressive. Here we investigated the effects of the combination on a mature cariogenic multispecies biofilm and analyzed the potential mechanism.
A multispecies biofilm of , , and was established . Dex and NaF were added separately or together. The effects of the agents on the biomass were measured. The exopolysaccharide production was determined with the scintillation counting method. The viability and morphology were evaluated using colony forming unit and confocal laser scanning microscopy, respectively.
In general, biofilms treated with Dex and a little concentration of NaF exhibited a lower biomass, exopolysaccharide production, and viability compared with the control group (P < 0.05). Confocal laser scanning microscopy using a vital fluorescence technique showed the combination treated biofilms appeared to be loose relatively and single cells could be observed. Furthermore, the thickness and viability were also lower than either of the separate agent groups (P < 0.05).
Overall, these findings reveal that a combination of 1 U/mL Dex and 80 μg/mL NaF is a promising candidate for disrupting complex cariogenic multispecies biofilms. This feature may be in that Dex loses the structure of biofilms, thereby facilitating NaF penetration and enhancing its antibacterial effects.
背景/目的：外源性葡聚糖酶（Dex）和氟化钠（NaF）对单一菌种生物膜的协同作用令人印象深刻。在此，我们研究了二者联合作用于成熟的致龋多菌种生物膜的效果，并分析其潜在机制。
建立变形链球菌、远缘链球菌和嗜酸乳杆菌的多菌种生物膜。分别单独或联合添加Dex和NaF。测定这些试剂对生物量的影响。用闪烁计数法测定胞外多糖的产生。分别使用菌落形成单位和共聚焦激光扫描显微镜评估生物膜的活力和形态。
总体而言，与对照组相比，用Dex和低浓度NaF处理的生物膜生物量、胞外多糖产生量和活力较低（P<0.05）。使用活体荧光技术的共聚焦激光扫描显微镜显示，联合处理的生物膜相对显得疏松，可观察到单个细胞。此外，其厚度和活力也低于单独使用任一试剂的组（P<0.05）。
总体而言，这些研究结果表明，1 U/mL Dex和80 μg/mL NaF的组合是破坏复杂的致龋多菌种生物膜的一个有前景的选择。这一特性可能在于Dex破坏了生物膜结构，从而促进NaF渗透并增强其抗菌效果。
