Antimicrobial peptides have been proposed as antibiofilm agents. Therefore, we evaluated the effect of endodontic irrigants combined or not with the antimicrobial peptide nisin against an endodontic biofilm model composed of eleven bacterial species. Biofilms were grown on hydroxyapatite discs for 3, 15 and 21 days and treated with 1.5% sodium hypochlorite (NaOCl) or 17% EDTA followed by high-purity nisin (nisin ZP) or saline for 5 min each. Differences between groups were tested by two-way ANOVA and Tukey’s multiple comparisons test (p < 0.05). Treatment with 1.5% NaOCl completely eliminated 3-d and 15-d biofilms but did not eradicate 21-d biofilms. Treatment with 1.5% NaOCl and 17% EDTA was equally effective against 21-d biofilms, showing 5-log and 4-log cell reduction, respectively, compared to the untreated control (9 log₁₀, p < 0.05). No significant difference was found between 1.5% NaOCl + nisin ZP and 1.5% NaOCl in 21-d biofilms (p > 0.05). Likewise, no significant difference was found between 17% EDTA + nisin ZP and 17% EDTA treatments (p > 0.05). In conclusion, 1.5% NaOCl or 17% EDTA were effective strategies to combat mature biofilms. The additional use of nisin did not improve the activity of conventional irrigants against multispecies biofilms.

中文翻译：

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次氯酸钠和 EDTA 联合高纯度乳酸链球菌肽对牙髓样生物膜模型的抗菌作用

已经提出抗微生物肽作为抗生物膜剂。因此，我们评估了牙髓冲洗剂与抗菌肽乳酸链球菌肽结合或不结合对由 11 种细菌组成的牙髓生物膜模型的影响。生物膜在羟基磷灰石圆​​盘上生长 3、15 和 21 天，并用 1.5% 次氯酸钠 (NaOCl) 或 17% EDTA 处理，然后用高纯度乳酸链球菌肽 (乳酸链球菌肽 ZP) 或盐水各处理 5 分钟。组间差异采用双向方差分析和 Tukey 多重比较检验（p< 0.05)。用 1.5% NaOCl 处理完全消除了 3 天和 15 天生物膜，但没有根除 21 天生物膜。与未处理的对照相比，用 1.5% NaOCl 和 17% EDTA 处理对 21 天生物膜同样有效，分别显示 5-log 和 4-log 细胞减少（9 log ₁₀，p < 0.05）。在 21 天生物膜中，1.5% NaOCl + 乳链菌肽 ZP 和 1.5% NaOCl 之间没有发现显着差异（p > 0.05）。同样，在 17% EDTA + 乳酸链球菌肽 ZP 和 17% EDTA 处理之间没有发现显着差异 ( p > 0.05)。总之，1.5% NaOCl 或 17% EDTA 是对抗成熟生物膜的有效策略。额外使用乳链菌肽并没有提高常规冲洗剂对多物种生物膜的活性。