次氯酸钠溶液对不同时期粪肠球菌生物膜的药物作用

摘要

背景：有研究指出粪肠球菌能在营养物质缺乏、抗菌药存在的恶劣环境中生存，形成再感染而影响根管再治疗效果。也有实验表明次氯酸钠溶液作为根管冲洗液对残留的粪肠球菌具有很强的清除作用。　　目的：建立不同时期粪肠球菌生物膜，研究不同浓度次氯酸钠溶液对其的作用效果。　　方法：建立对数期、稳定期、饥饿期粪肠球菌生物膜模型，以1%，2.5%，5.25%次氯酸钠溶液分别作用于各时期粪肠球菌生物膜表面30 s、5 min、10 min，同时用激光共聚焦显微镜观察用药后生物膜情况。　　结果与结论：在相同浓度次氯酸钠溶液作用下，饥饿期粪肠球菌生物膜中的活菌降低量低于稳定期与对数期粪肠球菌生物膜中的活菌降低量(P<0.05)；在1%次氯酸钠溶液作用下，稳定期与对数期粪肠球菌生物膜中的活菌降低量差异有显著性意义(P <0.05)；在2.5%，5.25%次氯酸钠溶液作用下，稳定期与对数期粪肠球菌生物膜中的活菌降低量差异无显著性意义(P>0.05)。在同一时期生物膜模型下，5.25%次氯酸钠溶液作用下的活菌降低量高于2.5%、1%次氯酸钠溶液作用下的活菌降低量(P<0.05)；2.5%次氯酸钠溶液作用下的活菌降低量高于1%次氯酸钠溶液作用下的活菌降低量，但仅在药物作用30 s时差异有显著性意义(P<0.05)。结果表明，在相同药物浓度、相同作用时间内，饥饿期粪肠球菌生物膜较对数期、稳定期粪肠球菌生物膜对次氯酸钠溶液更具耐药性；在相同作用时间内，5.25%次氯酸钠溶液对饥饿期粪肠球菌生物膜的杀菌效果最佳。%BACKGROUND:Studies have reportedEnterococcus faecalis can exist in environment which is lack of nutrients and antimicrobials to cause re-infection of the root canal. Sodium hypochlorite solution is shown to have strong scavenging action as a root canal flushing fluid to eliminate residualEnterococcus faecalis. OBJECTIVE:To explore the antibacterial effect of sodium hypochlorite onin vitro biofilm formation of Enterococcus faecalis in different phases. METHODS:Biofilm models of Enterococcus faecalis were established at exponential phase, stationary phase and starvation phase, and then the biofilms were exposed to various concentrations of sodium hypochlorite solutions (1.0%, 2.5%, 5.25%). The contact time was 30 seconds, 5 minutes and 10 minutes. The direct optical observation ofEnterococcus faecalis was conducted under confocal laser scanning microscope. RESULTS AND CONCLUSION:In the same concentration of sodium hypochlorite solutions, the biofilms of starved cels were more resistant to sodium hypochlorite than those formed in the exponential phase and stationary phase (P < 0.05). When the concentration of sodium hypochlorite was 1%, the reduction of viable cels showed significant difference between the exponential phase and stationary phase (P < 0.05). When the concentration of sodium hypochlorite was 2.5% and 5.25%, the reduction of viable cels in the exponential phase and stationary phase had no statistical difference (P > 0.05). For the biofilms at the same phase, 5.25% sodium hypochlorite reduced more viable cels than 2.5% and 1% sodium hypochlorite (P < 0.05), and 2.5% sodium hypochlorite also could reduce more viable cels than 1% sodium hypochlorite, but it only exhibited a significant difference when the contact time was 30 seconds (P < 0.05). These results show that under the same concentration and same contact time, theEnterococcus faecalis biofilms at the starvation phase are more resistant to sodium hypochlorite than those at the exponential phase and stationary phase. Under the same contact time, 5.25% sodium hypochlorite exhibits the best antibacterial effect on theEnterococcus faecalis biofilms at the starvation phase.