洗必泰溶液对不同时期粪肠球菌生物膜作用效果的实验研究

Effects of chlorhexidine solution on different stages of Enterococcus faecalis biofilms

目的:探讨洗必泰(chlorhexidine,CHX)溶液作为根管冲洗药物,对24 h和3 w粪肠球菌生物膜的灭菌作用。方法:在Ⅰ型胶原包被的羟磷灰石片上培养24 h和3 w粪肠球菌生物膜,应用2%CHX溶液处理5 min,扫描电镜观察细菌生物膜形态及结构的变化,激光共聚焦扫描显微镜观察灭菌效果。结果:在2%CHX溶液作用下,24h粪肠球菌生物膜可见明显破坏的细胞形态,3 w粪肠球菌生物膜失去原有的层级结构,镶嵌于生物膜之间胞外聚合物(extracellular polymeric substances,EPS)遭到破坏。24 h和3 w粪肠球菌生物膜经2%CHX溶液作用后死菌比例分别为(86.0±3.0)%和(38.6±2.0)%,无菌生理盐水几乎无杀灭细菌的能力。结论:洗必泰溶液对不同时期粪肠球菌生物膜均具有良好的杀灭效果;对年轻粪肠球菌生物膜表现为明显的胞体破坏作用,对成熟粪肠球菌生物膜的胞外聚合物具有明显的清除作用。

Objective ： To evaluate the antibacterial effect of chlorhexidine （CHX） solution as being one of the most common root canal irrigation medication on different stages of Enterococcus faecalis biofilms. Methods： Enterococcus faecalis biofilms were grown upon the hydroxyapatite disks which were coated with bovine dermal type I collagen in brain-heart infusion broth respectively for 24 hours and 3 weeks. Then biofilms of different stage were subjected to 5 minutes exposure to 2% chlorhexidine or normal saline（NS）. After treatment, the volume ratio of dead bacteria in biofilms was assessed by confocal laser scanning microscopy （CLSM）by using a LIVE/DEAD viability stain. Biofilm structure was visualized by scanning electron microscopy（SEM）. Results：When appling 2% CHX solution,on the one hand bacterial cells in biofilms of 24 hours were destructed obviously. On the other hand, extracellular polymeric substances （EPS）in 3 weeks biofilms were obliterated. The proportion of killed bacteria in young biofilms（24 hous）and mature biofilms（ 3 weeks）was respectively（ 38. 6 ±2. 0 ）% and（86. 0 ±3. 0）% ,while normal saline did not have the ability to kill bacteria（P 〈0. 05）. Conclusion：2% CHX solution has a outstanding antibacterial effect against different stages of Enterococcus faecalis biofilms, presenting a cell body destruction function in young biofilms and a obliteration function of extracellular polymeric substances in mature biofilms.