饥饿状态粪肠球菌生物膜胞外多糖的合成能力

目的探讨饥饿环境对粪肠球菌生物膜胞外多糖合成能力的影响。方法体外培养饥饿状态粪肠球菌形成48h生物膜,凝集素标记结合倒置荧光显微镜观察胞外多糖分布情况,提取饥饿状态浮游粪肠球菌和对数期、稳定期、饥饿状态粪肠球菌48h生物膜胞外多糖,蒽酮法定量分析比较胞外多糖合成能力。结果饥饿状态粪肠球菌形成的48h生物膜内胞外多糖呈云絮状,与细菌分布区域不完全一致;生物膜细菌合成水溶性和水不溶性胞外多糖的能力均高于浮游细菌(P<0.05);其合成水溶性胞外多糖的能力与对数期和稳定期细菌无显著差别(P>0.05),合成水不溶性胞外多糖的能力高于后两者(P<0.05)。结论饥饿状态粪肠球菌合成生物膜胞外多糖的能力增强。     

胞外DNA在根管粪肠球菌生物膜中作用的研究

目的:通过激光共聚焦显微镜(CLSM)观察脱氧核糖核酸酶Ⅰ(DNaseⅠ)对根管内粪肠球菌生物膜形成过程的影响,以研究胞外DNA在此生物膜形成过程中的作用。方法:在盖玻片上建立粪肠球菌生物膜模型,并在生物膜形成的不同时间,用DNaseⅠ处理,AO-EB染色,激光共聚焦显微镜观察生物膜的形态变化。结果:生物膜中胞外DNA随着生物膜的生长而增多;在有无DNaseⅠ存在的两种环境下,生物膜的形成情况发生了迥异的变化;DNaseⅠ对生物膜的生长具有抑制作用。结论:胞外DNA在根管内粪肠球菌生物膜形成过程中有着重要的作用。     

粪肠球菌生物膜细胞外聚合物的研究进展

粪肠球菌是根管治疗后再感染的主要致病菌,常以生物膜的形式存在。包绕在细菌周围或黏附在细菌表面的糖类、核酸和分泌蛋白对粪肠球菌的初始黏附、生物膜空间结构和细菌间信息交流等起重要的作用。本文就粪肠球菌生物膜及其细胞外聚合物组分和去除方法作一综述。     

持续性根尖周炎优势菌粪肠球菌生物膜形成能力的体外研究

目的：比较持续性根尖周炎优势细菌粪肠球菌( Enterococcus faecalis,E． faecalis)标准菌株与临床菌株生物膜体外形成能力。方法 E． faecalis 标准菌株 ATCC 29212及持续性根尖周炎分离的 E． faecalis 临床株lcl1709,体外形成生物膜,采用激光扫描共聚焦荧光显微镜(LSCM)观察并对比在12、24、36、48h时2种生物膜形成面积;使用96微孔板结晶紫染色法检测并比较在12、24、36、48h时两者生物膜形成量。结果 ATCC 29212菌株培养12、24、36、48h在离体牙根尖表面生物膜形成面积(μm2)分别为47．577±45．221,206．935±122．596,558．782±330．877,1865．023±702．539;lcl1709的为62．227±33．040,461．578±285．281,1211．077±515．262,2632．515±1332．914。36h与48h lcl1709形成的生物膜面积显著高于ATCC 29212(P<0．05)。12、24、36、48h的生物膜OD590值ATCC 29212菌株分别为0．048±0．001,0．130±0．025,0．148±0．022,0．137±0．021;lcl1709菌株分别为0．096±0．029,0．162±0．015,0．201±0．042,0．235±0．078。 lcl1709生物膜OD590值显著高于ATCC 29212(P<0．05),随时间延长,各组OD590值显著增大( P<0．05)。结论 E． faecalis可形成生物膜,持续性根尖周炎分离的E． faecalis菌株生物膜形成能力强于标准菌株,可能与其致病性密切相关。     

再感染根管内粪肠球菌生物膜的研究进展

粪肠球菌是顽固性和继发性根管感染中最易分离到的细菌,其主要致病机制之一是形成生物膜.笔者下面就再感染根管内粪肠球菌的分离与鉴定、影响粪肠球菌生物膜形成的相关因素等作一综述.     

碱性pH对浮游状态和生物膜状态粪肠球菌活性的影响

目的:比较生物膜状态与浮游状态下粪肠球菌对碱的耐受性。方法:制备浮游状态和生物膜状态的粪肠球菌细胞,用pH值分别为7、8、9、10、11和12的培养液作用2h,利用MTT比色法比较2种状态下细菌细胞活性变化。采用SAS6.12软件包对数据进行统计学分析。结果:低碱性环境(pH值7～9)对粪肠球菌的生长无明显影响,高碱性环境(pH值>10)下存活细菌的比例明显减少;高pH环境下,生物膜状态的粪肠球菌存活细菌比例显著高于浮游状态下细菌的存活比例。结论:粪肠球菌对碱性环境具有强耐受性,形成生物膜是粪肠球菌抵抗高碱性环境的一个重要原因。     

原子力显微镜观察粪肠球菌的超微结构及生物膜的动态形成过程

目的应用原子力显微镜（AFM）观察生理状态下粪肠球菌的表面超微结构及粪肠球菌生物膜的动态形成过程。方法利用AFM观察生理状态下粪肠球菌的超微结构并进行三维成像。利用硝酸纤维素薄膜在体外构建粪肠球菌生物膜模型,用AFM观察粪肠球菌生物膜形成过程中的表面变化。结果粪肠球菌菌体呈球状,表面凹凸不平,被颗粒状物包绕。初步确定了6 h粪肠球菌生物膜逐渐形成,24 h生物膜维持稳定状态,观察到细菌表面局部特征的变化及细菌胞外的多聚体物质。结论应用AFM能够在生理条件下清晰地观察粪肠球菌表面超微结构及粪肠球菌生物膜的整个动态形成过程。     

纳米银对牙本质表面粪肠球菌生物膜的杀菌作用

目的 研究纳米银对牙本质表面粪肠球菌生物膜的杀菌作用,为探寻新型有效的根管消毒药物提供实验依据.方法 制备牙本质片309个,随机分成3组,在牙本质表面形成粪肠球菌生物膜后,分别用0.1%纳米银溶液、1.313%次氯酸钠溶液和0.9%氯化钠溶液处理.3组分别于处理0(即处理前)、1、6、12、24 h时取出样本,应用活菌...     

再治疗根管粪肠球菌生物膜形成与临床表现相关性分析

目的检测粪肠球菌形成生物膜的能力,探讨其生物膜形成能力与临床表现之间的关系。方法采用96孔板法形成生物膜,结合结晶紫染色,检测临床样本中分离的53株粪肠球菌形成生物膜的能力,分析其生物膜形成能力与患牙临床表现之间的关系。结果53株粪肠球菌中,40株（75.47%）具有生物膜形成能力;在患牙的多种临床表现中,瘘道与再治疗根管粪肠球菌生物膜形成具有相关性,结果具有统计学意义（P＜0.05）。结论再治疗根管中,无瘘道的患牙分离出来的粪肠球菌生物膜形成能力强于有瘘道的患牙,临床治疗中应予以注意。     

In vitro Enterococcus faecalis biofilm formation on five adhesive systems

Objective: To determine the E. faecalis biofilm formation on the surface of five adhesive systems (AS) and its relationship with roughness. Study Design: The formation of E. faecalis biofilms was tested on the surface of four dual-cure AS: AdheSE DC, Clearfil DC Bond, Futurabond DC and Excite DSC and one light-cure antimicrobial AS, Clearfil Protect Bond, after 24 hours of incubation, using the MBEC high-throughput device. Results: E. faecalis biofilms grew on all the adhesives. The least growth of biofilm was on Excite DSC, Clearfil Protect Bond, and the control. Futurabond DC resulted in the greatest roughness and biofilm amount. There was a close relationship between the quantity of biofilm and roughness, except for Clearfil Protect Bond, which showed little biofilm but high roughness. Conclusion: None of the tested AS prevented E. faecalis biofilm formation, although the least quantity was found on the surface of Clearfil Protect Bond. Key words:Adhesive systems, biofilm, Enterococcus faecalis, roughness.     

Effectiveness of curcumin against Enterococcus faecalis biofilm

Abstract

Objectives. To evaluate the antimicrobial efficacy of curcumin against Enterococcus faecalis bio?lm formed on tooth substrate in vitro. Sodium hypochlorite (NaOCl) and chlorhexidine (CHX) served as standards for comparison. Materials and methods. Biofilms of E.faecalis were formed on instrumented, extracted human teeth (n = 96). At the end of the 2nd day, 2nd and 8th weeks, specimens were treated for 30 min with one of the test solutions or saline (control) and the surviving colony-forming units (CFU/mL) was recorded. Results were analyzed by Kruskal-Wallis test and Dunnet test for pair-wise comparison with Bonferroni correction (p = 0.05). Results. Only NaOCl showed complete eradication of bacteria at all time periods. In the 2-day and 2nd week biofilms, curcumin and NaOCl showed complete inhibition, which was significantly lower than the CFU recovered in the CHX and saline groups (p < 0.05). In 8 week biofilms, samples treated with curcumin showed 553 ± 137.6 CFU/mL, which was significantly higher than NaOCl (0 CFU/mL), but significantly lower than CHX (2551 ± 129.8) and saline control (1.42 × 1011 ± 2.12 × 1010; p < 0.05). Conclusions. Sodium hypochlorite (3%) showed maximum antibacterial activity against E.faecalis bio?lm formed on the tooth substrate, followed by curcumin and CHX. Considering the potential for undesirable properties of NaOCl, the use of herbal alternatives in endodontics might prove to be advantageous.     

粪肠球菌生物膜的药物敏感性研究

目的 建立体外粪肠球菌生物膜模型,评价10%氢氧化钙溶液和2%洗必泰溶液去除粪肠球菌生物膜的效果.方法 在玻片上形成4、8、12、24、48 h粪肠球菌生物膜,荧光染色后,采用激光共聚焦扫描显微镜(CLSM)观察;用10%氢氧化钙溶液和2%洗必泰溶液分别处理24 h生物膜3、10、30 min,采用CLSM观察;ANO...     

茶多酚、MTAD和次氯酸钠液抑制粪肠球菌及其生物膜的作用比较

目的:检测中药茶多酚、MTAD、52.5 g/L次氯酸钠抑制根管壁粪肠球菌生物膜的能力,并分析中药茶多酚作为根管冲洗液的可行性。方法:采用微孔板滴定法检测茶多酚,MTAD和52.5 g/L次氯酸钠液对粪肠球菌的最小抑菌浓度(MIC)和最小杀菌浓度(MBC),采用琼脂扩散实验检测3种抗菌剂对粪肠球菌的抑菌圈。通过建立粪肠球菌感染根管3周和6周的模型,分别用茶多酚、MTAD和52.5 g/L次氯酸钠液对粪肠球菌感染后的根管进行处理,然后对根管壁生物膜中的细菌生存情况进行定性定量分析,比较这3种根管冲洗液抗粪肠球菌生物膜的能力。结果:MIC、MBC和琼脂扩散实验显示:3组冲洗剂对粪肠球菌均有抑制作用。在粪肠球菌感染根管3周的生物膜中,MTAD和次氯酸钠液可以完全抑制粪肠球菌生物膜,茶多酚处理后虽仍有粪肠球菌生长,但明显低于生理盐水处理组的细菌生存数,差异有统计学意义(P<0.05)。在粪肠球菌感染根管6周的生物膜中,次氯酸钠液可以完全抑制细菌生长,茶多酚和MTAD作用后仍有活菌生长,但与对照组相比,细菌生存数均显示了8个log值的下降,差异有统计学意义(P<0.05)。结论:52.5 g/L次氯酸钠液具有很强的抑制根管内粪肠球菌生物膜作用,而茶多酚和MTAD也具有一定的抑制粪肠球菌生物膜的能力。     

Effect of the quorum‐sensing luxS gene on biofilm formation by Enterococcus faecalis

Enterococcus faecalis is the species of bacterium most frequently isolated from the root canals of teeth that exhibit chronic apical periodontitis refractory to endodontic treatment. In this study, we evaluated the effect of the S‐ribosylhomocysteine lyase (luxS) quorum‐sensing gene on E. faecalis biofilm formation by constructing a knockout mutant. The biofilms formed by both E. faecalis and its luxS mutant strain were evaluated using the MTT method. Important parameters that influence biofilm formation, including cell‐surface hydrophobicity and the nutrient content of the growth medium, were also studied. Biofilm structures were observed using confocal laser scanning microscopy (CLSM), and expression of biofilm‐related genes was investigated using RT‐PCR. The results showed that the luxS gene can affect biofilm formation, whereas it does not affect the bacterial growth rate. Deletion of the luxS gene also increased cell‐surface hydrophobicity. Biofilm formation was accelerated by the addition of increasing concentrations of glucose. The CLSM images revealed that the luxS mutant strain tends to aggregate into distinct clusters and relatively dense structures, whereas the wild‐type strain appears confluent and more evenly distributed. All genes examined were up‐regulated in the biofilms formed by the luxS mutant strain. The quorum‐sensing luxS gene can affect E. faecalis biofilm formation.     

The role of environmental changes on monospecies biofilm formation on root canal wall by Enterococcus faecalis

Biofilm mode of growth is a strategy in microorganisms to survive harsh growth conditions. Although previous studies have established the ability of Enterococcus faecalis to survive postendodontic environmental conditions, the effect of such conditions on the ultrastructural and physiochemical features of E. faecalis biofilm has received less attention. This study aims to evaluate the effect of different growth conditions on the characteristics of E. faecalis biofilm on root canal, and the penetration of E. faecalis into dentinal tubules. Forty-five intact noncarious human maxillary molars were experimented under nutrient-rich, nutrient-deprived, aerobic, and anaerobic conditions for a period of 21 days. Scanning Electron Microscopy with Energy Dispersive X-ray microanalysis, Laser Confocal Scanning Microscopy and Light microscopic examinations were carried out. The microscopic analysis highlighted a distinct variation in the ultrastructure of the biofilms formed under different experimental conditions. The EDX microanalysis showed a significant increase in the levels of Calcium (Ca) in the biofilm structures formed under anaerobic nutrient-deprived condition (p < 0.001). The depth of bacterial penetration was significantly greater in nutrient-rich condition (p < 0.001). This study demonstrated distinct ultrastructural and physiochemical properties of the biofilms formed and dentinal tubular penetration of E. faecalis under different conditions.     

电解质水对粪肠球菌生物膜的杀菌作用研究

目的:观察强酸性电解质水(SAEW)和碱性电解质水(AEW)对粪肠球菌生物膜的杀菌作用。方法:利用BioFluxTM200微流体系统建立粪肠球菌生物膜模型,并分别用SAEW、AEW、52.5 g/L次氯酸钠液(阳性对照)和生理盐水(阴性对照)处理1、5、10 min后,激光共聚焦显微镜(CLSM)观察并采集荧光图像;ImageJ图像分析软件分析并计算各处理组不同时间点的活菌比例。结果:SAEW、AEW和52.5 g/L次氯酸钠液处理1、5、10 min各时间点的活菌比例都显著低于生理盐水组(P<0.05),其中AEW组活菌比例下降幅度最小,与SAEW和52.5 g/L次氯酸钠液处理组相比,各时间点均有统计学差异(P<0.05);而SAEW与52.5 g/L次氯酸钠液处理组相比,各时间点的活菌比例均无统计学差异(P>0.05)。结论:SAEW和AEW对粪肠球菌均有杀菌作用,其中SAEW的作用与52.5 g/L次氯酸钠液相当;而AEW的杀菌效果较弱,且需要延长作用时间。