Restorative and Dental Materials Department, Oral and Dental Research Division, National Research Centre, 33 El-Buhouth St. (Former El Tahrir St), 12622, Dokki, Cairo, Egypt.
Chemistry of Natural and Microbial Products Department, Pharmaceutical and Drug Industries Research Division, National Research Centre, 33 El-Buhouth St. (Former El Tahrir St), 12622, Dokki, Cairo, Egypt.
Microb Pathog. 2019 Oct;135:103626. doi: 10.1016/j.micpath.2019.103626. Epub 2019 Jul 17.
Plaque-related diseases are amongst the most common ailments of the oral cavity. Streptococcus mutans is the causal agent of dental caries in animals and humans and is responsible for the formation and accumulation of plaques. This study aimed to identify and evaluate the role of the dental plaque isolates and its surrounding environment in plaque formation or inhibition. The study started with the identification of human dental plaque isolates from high caries index patients based on 16S rRNA and Mitis salivarius bacitracin agar (MSB) was used for S. mutans growing. Unexpectedly, the Streptococcus mutans was completely absent. The disc diffusion assay recorded that all the isolates had antimicrobial activity against the S. mutans growth. Enzymes assay revealed that the isolates produced dextransucrase, levansucrase and levanase activity with wide variation degrees. Also, the lactic acid production assay was done based in pH shift assessment. The highest pH shift and dextran yield were detected by the isolates Bacillus subtilis_AG1 and Bacillus mojavensis_AG3. The adherence test revealed that Lysinibacillus cresolivorans_W2 (MK411028) recorded the highest adhesion property (60%). Oligo- and polysaccharides were synthesized by the action of dextransucrase enzyme and their cytotoxicity tests were negative. Dextran with a molecular weight (117521 Da) recorded the highest antimicrobial efficacy against Bacillus subtilis_AG1 and Bacillusmojavensis_AG3 (65%, 63.5%) respectively. The results concluded that the dextran was the most important factor causing the dental plaque pathogenicity. Also, oral oligo- and polysaccharides might play a role in dental plaque control.
菌斑相关疾病是口腔最常见的疾病之一。变形链球菌是动物和人类龋齿的病原体，负责菌斑的形成和积累。本研究旨在鉴定和评估牙菌斑分离物及其周围环境在菌斑形成或抑制中的作用。该研究首先从高龋指数患者的人牙菌斑分离物中鉴定出 16S rRNA，并使用米氏链球菌杆菌素琼脂（MSB）培养变形链球菌。出乎意料的是，变形链球菌完全不存在。圆盘扩散试验记录表明，所有分离物对变形链球菌的生长都具有抗菌活性。酶试验表明，分离物产生葡聚糖转移酶、莱氏聚糖酶和莱氏酶活性，且具有广泛的变化程度。此外，还进行了基于 pH 值变化评估的乳酸生成试验。分离物枯草芽孢杆菌_AG1 和摩氏芽孢杆菌_AG3 产生的最高 pH 值变化和葡聚糖产量。粘附试验表明，赖氨酸芽孢杆菌_W2（MK411028）具有最高的粘附特性（60%）。寡糖和多糖通过葡聚糖转移酶的作用合成，其细胞毒性试验为阴性。分子量为 117521 Da 的葡聚糖对枯草芽孢杆菌_AG1 和摩氏芽孢杆菌_AG3 的抗菌效果最高（分别为 65%，63.5%）。结果表明，葡聚糖是导致牙菌斑致病性的最重要因素。此外，口腔寡糖和多糖可能在控制牙菌斑中发挥作用。
