Lactic acid bacteria have been widely used as probiotics for improving gut health. However, studies on oral probiotics were very limited. In this study, 67 lactic acid bacteria (LAB) were isolated from fermented food and screened for antagonistic activity against Streptococcus mutans, the causative pathogen of dental caries. Leuconostoc mesenteroides MJM60376 showed the highest antagonistic activity against S. mutans KCTC3065. L. mesenteroides MJM60376 also showed oral probiotic characteristics including weak acid production, lysozyme tolerance, adhesion to oral epithelial cell (YD-38), antibiotic susceptibility, and good coaggregation ability with S. mutans. Furthermore, the biofilm formation of S. mutans was significantly reduced when cocultured with L. mesenteroides. Scanning electron microscopy analysis showed that amounts of attached bacteria of S. mutans and network-like structures were significantly reduced by L. mesenteroides MJM60376. Cell-free supernatant (CFS) of L. mesenteroides MJM60376 also greatly inhibited biofilm formation of S. mutans from the adherent stage, the activity remained even after it was treated with catalase, trypsin, or pH neutralized. Expression levels of biofilm formation-related genes were significantly reduced in S. mutans when it was treated with the CFS of L. mesenteroides MJM60376. Therefore, L. mesenteroides MJM60376 has great potential to be used as a multifunctional ingredient.

中文翻译：

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肠膜明串珠菌 MJM60376 作为口服益生菌的特性及其抗生物膜活性

乳酸菌已被广泛用作改善肠道健康的益生菌。然而，关于口服益生菌的研究非常有限。在这项研究中，从发酵食品中分离出 67 种乳酸菌 (LAB)，并筛选其对龋齿病原体变形链球菌的拮抗活性。肠膜明串珠菌MJM60376 显示出对变形链球菌KCTC3065的最高拮抗活性。L. mesenteroides MJM60376 还表现出口腔益生菌特性，包括弱酸产生、溶菌酶耐受性、对口腔上皮细胞 (YD-38) 的粘附、抗生素敏感性以及与变形链球菌的良好共聚集能力。此外，生物膜的形成当与L. mesenteroides共培养时， S. mutans显着减少。扫描电子显微镜分析表明， L. mesenteroides MJM60376显着减少了变形链球菌和网络状结构的附着细菌数量。L. mesenteroides MJM60376的无细胞上清液 (CFS)也极大地抑制了S. mutans从粘附阶段形成生物膜，即使在用过氧化氢酶、胰蛋白酶处理或 pH 中和后，活性仍然存在。当用L. mesenteroides MJM60376的 CFS 处理时，变形链球菌中生物膜形成相关基因的表达水平显着降低。所以，L. mesenteroides MJM60376 具有用作多功能成分的巨大潜力。