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。     

粪肠球菌与难治性根尖周炎相关性的Meta分析

目的系统评价粪肠球菌和难治性根尖周炎之间的相关性。方法计算机检索PubMed、ScienceDirect、EMbase、万方数据、CNKI、维普等数据库,全面收集有关难治性根尖周炎中粪肠球菌检出率的独立队列研究、病例-对照研究以及横断面研究,并追溯所获文献的参考文献,检索时限均从建库至2013年12月。按纳入和排除标准筛选文献、提取资料和评价质量后,采用Stata 12.0软件进行统计分析。结果最终纳入18项研究,共728例难治性根尖周炎病例和748例对照病例。 Meta分析结果显示,难治性根尖周炎中粪肠球菌的检出率明显高于对照病例,差异有统计学意义[OR＝3.559,95％ CI（1.696,7.470）,P＜0.05]。亚组分析和敏感性分析结果与上述结果一致。结论粪肠球菌与难治性根尖周炎间存在较为密切的关联,但具体机制仍待进一步研究。受纳入研究质量和数量所限,上述结论尚需今后开展更多高质量的研究加以验证和更新。     

粪肠球菌与复发性根尖周炎的相关性及其机制

粪肠球菌可在恶劣的环境中持续生长和繁殖,而在生物膜中具有的极强的生存和致病能力,使其成为根尖周炎复发的重要的致病因素。粪肠球菌的毒力因子,可引起健康组织损伤,增强细菌的黏附能力。粪肠球菌的检出率,在原发性感染根管内为7.5%,但在治疗失败的感染根管中可达到70%以上,即粪肠球菌在原发性根尖周炎患牙的根管内并非主要致病菌。粪肠球菌在根管冠1/3段的感染较重,在根中1/3和根尖1/3段的感染较轻。粪肠球菌对常规的根管消毒和抗菌药物有极强的耐药性,很难用传统的方法将其于根管内彻底清除,因此研发可以有效地抑制或杀灭粪肠球菌药物十分必要。     

难治性根尖周炎根尖生物膜内粪肠球菌的检出及临床意义

目的探讨难治性根尖周炎根尖生物膜内的粪肠球菌的检出率,分析粪肠球菌的检出率与临床表现的关系。方法按纳入标准收集需要进行根尖外科手术的单根管患牙42颗,记录症状和体征,采集根尖生物膜样本,各样本均采用生化鉴定和聚合酶链反应(PCR)两种方法检测粪肠球菌。统计学分析两种方法对粪肠球菌的检出率差异及其与患者症状体征之间的关系。结果生化鉴定和PCR检测难治性根尖周炎根尖生物膜内粪肠球菌的检出率分别为52.4%和71.4%,差异有统计学意义(P<0.05)。PCR检测发现在疼痛组粪肠球菌的检出率高于无疼痛组(P<0.05)。结论 PCR检测难治性根尖周炎根尖生物膜内粪肠球菌检出率较高,且粪肠球菌的检出与疼痛存在相关性。     

慢性根尖周炎感染根管内粪肠球菌和白色念珠菌的检测

目的检测未经治疗和根管再治疗的慢性根尖周炎感染根管内粪肠球菌和白色念珠菌,探讨粪肠球菌和白色念珠菌与慢性根尖周炎发病的关系。方法选取未经根管治疗和需根管再治疗的慢性根尖周炎病例各30例,采集根管内细菌样本,提取DNA,分别设计粪肠球菌和白色念珠菌的引物进行PCR检测。结果所有根管内均可检测到细菌。粪肠球菌在慢性根尖周炎根管再治疗病例中检出率为53.3%(16/30),慢性根尖周炎未经根管治疗病例的根管为10%(3/30)。白色念珠菌仅检出2例,均在慢性根尖周炎根管再治疗病例中检出(6.67%),而未经根管治疗病例的检出率为0。结论粪肠球菌和白色念珠菌在原发的慢性根尖周炎感染根管中检出率较低,在再治疗根管中检出率增高,可能与根管治疗时再感染有关。     

营养缺乏和碱性环境对粪肠球菌侵入人工微管系统的影响

目的:研究不同环境因素对粪肠球菌侵入人工微管系统能力的影响和微流芯片的适用性.方法:采用软光刻技术制作微流芯片,观察细菌在牛脑心浸出液(BHI)、PBS和pH 10的情况下在微流芯片中的生长情况,测定和比较细菌在相应微管内的最大侵入深度.结果:粪肠球菌在营养缺乏和碱性环境下生长速度明显下降,侵入小管径微管的深度显著下降(P＜0.01).结论:营养缺乏和碱性环境可显著降低粪肠球菌侵入微管系统的能力.微流芯片具有高通量、平行对比和可观察性好等特点,有望为今后相关研究提供标准化的实验平台.     

再治疗根管内粪肠球菌的分离鉴定及其相关特性研究

目的:研究粪肠球菌在再治疗根管内的检出率及其相关特性(生长情况、生物膜形成能力及耐药性)。方法:收集临床病例样本54例,使用粪肠球菌选择性培养基和胆盐七叶苷琼脂进行分离培养。分离株通过16SrRNA测序法鉴定。将鉴定正确的粪肠球菌临床分菌株和作为对照的粪肠球菌标准株(EfATCC29212)用BHI培养基进行培养,分别对比其生长曲线、生物膜形成能力及耐药性。结果:收集临床病例样本54例,分离鉴定为粪肠球菌的有18例,检出率为33.33%。经统计分析:粪肠球菌在再治疗根管内的检出率在病人性别、年龄、患牙尖周稀疏大小及距离上次根管治疗时间长短等方面无统计学差异(P>0.05);但与上次根管治疗根充是否到位有关,欠填根管中粪肠球菌的检出率明显高于恰填根管(P<0.05),但不同欠填长度组间粪肠球菌的检出率无统计学差异(P>0.05)。此外,粪肠球菌临床分离株与对照菌株在生长曲线、生物膜形成能力及耐药性等方面均无统计学差异(P>0.05)。结论:粪肠球菌在再治疗根管内的检出率为33.33%,其检出率与上次根管治疗根充情况有关。同时,粪肠球菌临床分离株与标准株的生长情况、生物膜形成能力及耐药性基本一致。     

粪肠球菌与根尖周炎溶骨相关信号分子研究进展

难治性根尖周炎以骨吸收为主要特征之一.粪肠球菌是治疗后根管再感染的重要致病菌,脂磷壁酸(lipoteichoicacid,LTA)是其主要免疫原.本文对近年国内外粪肠球菌诱导骨破坏信号通路的新进展作出综述.     

粪肠球菌与根尖周炎溶骨相关信号分子研究进展

难治性根尖周炎以骨吸收为主要特征之一。粪肠球菌是治疗后根管再感染的重要致病菌,脂磷壁酸（lipoteichoicacid,LTA）是其主要免疫原。本文对近年国内外粪肠球菌诱导骨破坏信号通路的新进展作出综述。     

粪肠球菌及其在牙本质小管内的检测和鉴定

粪肠球菌的抗饥饿能力较强,可在非常苛刻的环境下生存。在根管内的不同部位,粪肠球菌的定植密度不同。粪肠球菌具有的多种毒力因子,可在肠球菌菌种之间转移扩散,耐受宿主的非特异性免疫应答,增强其致病性和生存能力。本文就粪肠球菌的特点,牙本质小管内粪肠球菌的检测与鉴定等研究进展作一综述。     

Bacteriophages induced from lysogenic root canal isolates of Enterococcus faecalis

Introduction:  Bacterial viruses play crucial roles in the pathogenesis of many systemic diseases. They are known to inhabit the oral cavity, both as free virions and as prophages in lysogenic bacterial strains; however, there has been no report of bacteriophages in endodontic infections. In this study, we sought to detect, isolate, and describe temperate bacteriophages harbored by Enterococcus faecalis strains isolated from endodontic infections.
Methods:  Ten E. faecalis strains were isolated from root canals of teeth undergoing retreatment following unsuccessful endodontic therapy. Mitomycin C was used to induce any prophages present in the bacterial isolates. The induced phages were purified and examined using electron microscopy. The DNA extracted from one of the phage isolates was subjected to restriction endonuclease digestion and agarose electrophoresis analysis.
Results:  Lysogeny was demonstrated in 4 of the 10 E. faecalis strains. Three of the lysogenic strains yielded phages exhibiting a Siphoviridae morphology, with long, non-contractile tails 130 nm in length, and spherical/icosahedral heads 41 nm in diameter. The virus induced from the fourth lysogenic E. faecalis strain had a contractile tail characteristic of Myoviridae. Restriction endonuclease analysis of Nsi I and Nde I DNA fragments from one of the Siphoviridae phage isolates (phage φEf11) indicated a genome size of approximately 41 kbp.
Conclusion:  This is the first report of lysogenic bacteria and their inducible viruses in infected root canals.     

Assessment of antimicrobial susceptibility of Enterococcus faecalis isolated from chronic periodontitis in biofilm versus planktonic phase

Background: Enterococci are often associated with chronic and recurrent infectious diseases because of their antimicrobial resistance. The aim of this study is to assess antimicrobial susceptibility of Enterococcus faecalis in chronic periodontitis. Methods: Antimicrobial susceptibility was determined on 23 E. faecalis strains isolated from patients with chronic periodontitis. Ampicillin, erythromycin, gentamicin, tetracycline, triclosan, and vancomycin were prepared in two‐fold serial dilution up to 8,192 μg/mL. Enterococcal biofilm was established by a biofilm device and observed by confocal laser microscopy and scanning electron microscopy. The minimum inhibitory concentration (MIC), minimum biofilm inhibitory concentration, and minimum biofilm eradication concentration were determined by spectrophotometer at optical density₆₅₀. Results: A few patches of monolayer early biofilm were observed on the surfaces of biofilm device pegs. The colony‐forming units of biofilm per peg were 1.2 × 10³ to 1.7 × 10⁴ and 0 to 20 post‐triclosan treatment. The MIC₅₀ was higher than the MIC epidemiologic cut‐off for tetracycline and the MIC₉₀ was higher than the cut‐off for erythromycin and tetracycline, respectively. In biofilm, minimum biofilm eradication concentrations were extremely high for all of the drugs except triclosan. Conclusions: The E. faecalis strains of chronic periodontitis exhibited weak biofilm formation ability at the early stage. Over 50% of the strains were resistant to tetracycline, and a few strains were highly resistant to erythromycin or gentamicin. E. faecalis cells in biofilm were hardly eradicated by most of the agents, even in high concentrations. Triclosan was effective in inhibiting E. faecalis growth in both biofilm and planktonic phase.     

粪肠球菌在口腔及全身系统性疾病中的致病相关因素及其机制的研究进展

作为人类口腔中根管再感染和难治性根尖周炎中的主要致病菌,粪肠球菌能够在根管内恶劣的环境中长期生存,对大多数根管治疗药物和清理消毒的方法都具有一定的抗性,是目前根管治疗的棘手之处。除此之外,它还与一些全身系统性感染,如胃肠道感染、尿道感染等有关。粪肠球菌的致病性与其对宿主的初始黏附、生物膜形成和入侵感染有关。粪肠球菌主要通过表达各种蛋白和糖脂等黏附相关因子实现初始黏附,随后通过调节各种生物膜相关基因的表达形成成熟的生物膜,以对抗机体的杀伤并实现细胞间的交流,最终定植到人体各个部位乃至引起全身感染。本文就粪肠球菌的致病相关因素及其机制的研究进展进行综述。     

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。     

再治疗根管内粪肠球菌检出及其与临床表征关系的分析研究

目的检测临床再治疗根管内的粪肠球菌,分析粪肠球菌检出率与临床症状及体征之间的关系。方法临床收集需根管再治疗的患牙108颗,记录症状和体征,根管内采集细菌样本,提取细菌基因组DNA,用聚合酶链反应定性检测粪肠球菌。结果根管内粪肠球菌的检出率为47.2%。在有症状病例、有体征病例、既有症状又有体征病例中,根管内粪肠球菌的检出率分别为52.6%、57.9%、62.5%,其中,有体征病例与无体征病例粪肠球菌的检验率差异有统计学意义（P＜0.05）,既有症状又有体征病例与无体征病例组粪肠球菌的检出率差异有统计学意义（P＜0.05）;在有症状的病例组中,有咬合痛的病例粪肠球菌的检出率为66.7%,与无咬合痛病例组相比差异有统计学意义（P＜0.05）。结论再治疗根管内粪肠球菌的存在与临床症状或体征密切相关。     

Antimicrobial susceptibility of Enterococcus faecalis isolated from canals of root filled teeth with periapical lesions

AIM: To test, in vitro, the susceptibility to different antibiotics of Enterococcus faecalis isolates from canals of root filled teeth with periapical lesions. METHODOLOGY: Twenty-one E. faecalis isolates, from canals of root filled teeth with persisting periapical lesions, were tested for their antibiotic susceptibilities. The following antibiotics were used: benzylpenicillin, amoxicillin, amoxicillin-clavulanic acid, erythromycin, azithromycin, vancomycin, chloramphenicol, tetracycline, doxycycline, ciprofloxacin and moxifloxacin. Minimal inhibitory concentrations (MICs) for the antimicrobial agents were determined using the E-test System (AB BIODISK, Solna, Sweden), and the E. faecalis strains classified as susceptible or resistant according to the guidelines of National Committee for Clinical Laboratory Standards (NCCLS). The strains were also tested for beta-lactamase production with nitrocefin (Oxoid, Basingstoke, UK). RESULTS: All strains were susceptible to penicillins in vitro, however, the MICs of amoxicillin and amoxicillin-clavulanic acid (MIC(90) = 0.75 microg mL(-1)) were lower than for benzylpenicillin (MIC(90) = 3.0 microg mL(-1)). All strains studied were also susceptible to vancomycin and moxifloxacin, whilst 95.2% were susceptible to chloramphenicol. Amongst the isolates, 85.7% were susceptible to tetracycline and doxycycline and 80.9% to ciprofloxacin. The MIC of erythromycin ranged from 0.38 to >256 microg mL(-1); only 28.5% of the strains were susceptible (MIC < or = 0.5 microg mL(-1)). Limited susceptibility was also observed with azithromycin which was active against only 14.2% of isolates. No strains produced beta-lactamase. CONCLUSION: Enterococcus faecalis isolates were completely susceptible, in vitro, to amoxicillin, amoxicillin-clavulanic acid, vancomycin and moxifloxacin. Most isolates were susceptible to chloramphenicol, tetracycline, doxycycline or ciprofloxacin. Erythromycin and azithromycin were least effective.     

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.