ABSTRACT

Background

Limitations of current intracanal irrigants such as sodium hypochlorite (NaOCl) and chlorhexidine (CHX) necessitate the development of novel antimicrobial agents to control endodontic infection.

Aim

This study investigated the antimicrobial activities of a small molecule II-6s against Enterococcus faecalis associated with endodontic diseases.

Methods

The susceptibility of E. faecalis to II-6s was evaluated by the microdilution method and time-kill assay. Microbial resistance was assessed by repeated exposure of E. faecalis to II-6s. Cytotoxicity of II-6s was evaluated by CCK-8 assay. Virulence gene expression of the II-6s-treated E. faecalis cells was measured by RT-qPCR. Bacterial reductions in the dentinal tubules were further assessed by confocal laser scanning microscopy.

Results

II-6s exhibited potent antimicrobial activity against E. faecalis and down-regulated virulence-associated genes in E. faecalis. II-6s induced no drug resistance in E. faecalis with lower cytotoxicity as compared to NaOCl and CHX. More importantly, 0.003125% II-6s exhibited significant bactericidal effect against E. faecalis residing in the dentinal tubules, which was comparable to 5.25% NaOCl and 2% CHX.

Conclusions

II-6s has excellent antimicrobial activity, moderate cytotoxicity and induces no drug resistance, and thus is a promising agent for the treatment of endodontic infection.

中文翻译：

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小分子 II-6s 抑制粪肠球菌生物膜

摘要

背景

当前根管内冲洗剂如次氯酸钠 (NaOCl) 和洗必泰 (CHX) 的局限性需要开发新型抗菌药物来控制牙髓感染。

目标

本研究调查了一种小分子 II-6s 对与牙髓疾病相关的粪肠球菌的抗菌活性。

方法

粪肠球菌对 II-6s的敏感性通过微量稀释法和时间杀灭法进行评估。通过将粪肠球菌反复暴露于 II-6s 来评估微生物抗性。通过CCK-8测定评估II-6s的细胞毒性。通过 RT-qPCR 测量II-6s 处理的粪肠球菌细胞的毒力基因表达。通过共聚焦激光扫描显微镜进一步评估牙本质小管中的细菌减少。

结果

II-6s 表现出对粪肠球菌的有效抗菌活性，并下调了粪肠球菌中的毒力相关基因。与 NaOCl 和 CHX 相比， II-6s 在E. faecalis中没有诱导耐药性，具有较低的细胞毒性。更重要的是，0.003125% II-6s 对牙本质小管中的粪肠球菌具有显着的杀菌作用，与 5.25% NaOCl 和 2% CHX 相当。

结论

II-6s具有优异的抗菌活性、中等的细胞毒性和无耐药性，是治疗牙髓感染的一种有前途的药物。