Analysis of bacterial biofilms as a virulence factor for refractory periapical periodontitis

细菌生物膜作为难治性根尖周炎毒力因子的分析

基本信息

批准号：
11470404
负责人：
EBISU Shigeyuki
金额：
$ 7.55万
依托单位：
Osaka University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B).
财政年份：
1999
资助国家：
日本
起止时间：
1999 至 2000
项目状态：
已结题

项目摘要

We morphologically examined the clinical specimens obtained from extracted teeth with refractory periapical periodontitis, canal filling materials excessively filled, and apical tooth fragment. In 9 of 11 samples, bacterial biofilms covered with glycocalyx-like structure were detected at the extraradicular area of canal filling materials and periapical root surface in electron microscopic observation. Filaments, long rods and spirohete-shaped bacteria were predominant in the biofilms at extraradicular sites of canal filling materials and planktonic cells emigrated from the glycocalyx-like structure, were also detected in several sites.Next, we generated the Porphyromonas gingivalis biofilms by use of modified Robbins device (MRD), and we investigated the biofilms morphologically as well as biological activity compared to their planktonic counterparts, using ATP assay based on luminescence generated by luciferase-luciferin interaction. The rate of increase of intracellular ATP concentra … More tion of the planktonic bacteria at log phase was 13.88 nmol/h, while that of mature biofilms after 14 days were 5.05 X 10^<-2> pmol/h, and these results indicated that growth rate of P.gingivalis in mature biofilms were about 1/3.0 X 10^5 of their planktonic counterparts. Formation of biofilms was observed 7 days after circulation in MRD and there was co-relation with the morphological changes of biofilms and increase of intracellular ATP concentration.To investigate antimicrobial susceptibility of P.gingivalis biofilms, we examined the effects of antimicrobial agents such as chlorhexidine, minocycline-hydrochloride and metronidazole against P.gingivalis biofilms, using ATP assay. ATP concentration was decreased to 1/1000 after incubation with chlorhexidine for a day, and thereafter ATP concentration were gradually decreased. In contrast, ATP concentration after 7 days incubation with minocycline-hydrochloride and metronidazole, were about a half of that of control. These results indicate that minocycline-hydrochloride and metronidazole have no significant bactericidal effects against P.gingivalis formed biofilms. Less

我们对患有难治性根尖周炎、根管充填材料过度填充和根尖牙碎片的拔除牙齿的临床标本进行了形态学检查，在11个样本中的9个样本中，在根管外区域检测到了覆盖有糖萼样结构的细菌生物膜。电镜观察，充填材料和根尖表面生物膜中以丝状、长杆状和螺旋状细菌为主。在多个位点也检测到根管充填材料和从糖萼样结构迁移出的浮游细胞的根外位点。接下来，我们使用改良的罗宾斯装置（MRD）生成牙龈卟啉单胞菌生物膜，并对生物膜进行形态学研究与它们的浮游单位相比，使用基于荧光素酶测定-荧光素相互作用产生的发光的 ATP 作为生物活性的增加率。浮游细菌对数生长期的胞内 ATP 浓度为 13.88 nmol/h，而 14 天后成熟生物膜的胞内 ATP 浓度为 5.05 X 10^<-2> pmol/h，这些结果表明 P 的生长速率成熟生物膜中的.gingivalis约为1/3.0为了研究牙龈卟啉单胞菌生物膜的敏感性，我们检测了氯己定、盐酸米诺环素和甲硝唑等抗菌药物对牙龈卟啉单胞菌生物膜的敏感性。 .gingivalis 生物膜，使用 ATP 测定后，ATP 浓度降至 1/1000。氯己定一天后，ATP浓度逐渐下降，而与盐酸米诺环素和甲硝唑一起孵育7天后，ATP浓度约为对照的一半。这些结果表明，盐酸米诺环素和甲硝唑没有显着差异。细菌对牙龈卟啉单胞菌形成的生物膜的影响较小。