口腔放线菌对白假丝酵母菌拮抗作用的体外实验研究

目的观测3种口腔放线菌对白假丝酵母菌的生长有无抑制作用。方法采用直接点种法观察抑菌圈,分别采用反点种菌落计数法和液体共培养法,观察在口腔放线菌作用下白假丝酵母菌菌落数量的变化。结果1）各实验组均未观察到清晰的抑菌圈;2）在黏性放线菌软琼脂上的白假丝酵母菌菌落数较对照组明显减少（P<0.05）;在溶牙放线菌和内氏放线菌软琼脂上无明显白假丝酵母菌生长,与对照组相比差异有统计学意义（P<0.01）;黏性放线菌组与溶牙放线菌组、内氏放线菌组相比,白假丝酵母菌生长差异有统计学意义（P<0.01）;3）分别与3种放线菌共培养的白假丝酵母菌菌落数量减少,与对照组相比差异有统计学意义（P<0.05）;3个实验组间差异无统计学意义（P＞0.05）。结论口腔黏性放线菌、溶牙放线菌和内氏放线菌对白假丝酵母菌的体外生长有抑制作用。     

口腔链球菌对白假丝酵母菌的拮抗作用

目的 观测3种口腔链球菌对白假丝酵母菌的生长有无抑制作用.方法 采用直接点种法、反点种菌落计数法和液体共培养法观测口腔变异链球菌、血链球菌、唾液链球菌对白假丝酵母菌的拮抗作用.结果 1)直接点种法中各组均未观察到清晰的抑菌圈;2)唾液链球菌软琼脂上的白假丝酵母菌菌落数较对照组减少(P<0.05);3)活菌与白假丝酵母菌...     

法尼醇对白念珠菌和粪肠球菌混合生物膜体外抑制作用的研究

目的 探讨法尼醇对白念珠菌和粪肠球菌混合生物膜的抑制作用.方法 采用微量平板法制备24 h和48 h白念珠菌和粪肠球菌混合生物膜,每组膜分别加入不同浓度法尼醇(100～800μmol/L)培养24 h,XTT减低法检测法尼醇对白念珠菌和粪肠球菌混合生物膜的抑制作用,倒置显微镜下观察混合生物膜形态,激光共聚焦显微镜下观察...     

化疗患者口腔白假丝酵母菌的分布及基因分组研究

目的研究以白假丝酵母菌（S.albicans）为代表的假丝酵母菌在化疗肿瘤患者口腔中的分布情况,并对检出的白假丝酵母菌进行基因分组。方法从390例接受化疗1年以上的肿瘤患者口腔中取样,采用颊黏膜拭子法,CHROMagar CandidaTM鉴定培养基初步鉴定,根据白假丝酵母菌25S rDNA基因多态性设计引物,根据PCR产物多态性进行基因分组。结果肿瘤患者口腔假丝酵母菌检出率为53.85％（210/390）,白假丝酵母菌的检出率为48.21％（188/390）,其余为光滑假丝酵母菌5.64%（22/390）;白假丝酵母菌基因分组A、B、C组均有检出,其中以B组为主,59.57%（112/188）。结论肿瘤患者口腔的假丝酵母菌以白假丝酵母菌为主,与健康人群的口腔白假丝酵母菌A组占有绝对多数的情况不同,B组白假丝酵母菌在化疗患者口腔中占主导地位。     

有机硅季铵盐浸泡纯钛对白假丝酵母菌生长的抑制作用

目的 通过有机硅季铵盐溶液浸泡处理纯钛试件,研究该方法对白假丝酵母菌的抗菌效果.方法 制作纯钛试件,将其随机分为A～F的6组,A～E组分别用浓度为1％、5％、10％、30％、60％的有机硅季铵盐溶液对纯钛试件进行抗菌处理,F组用蒸馏水浸泡处理作为对照,每组再分4小组,各小组处理时间分别为30、60、120、240 min,用比浊法统计分析有机硅处理后的纯钛试件对白假丝酵母菌生长的影响.将试件分别进行0、2 500、5 000、10 000次的冷热循环实验后再进行细菌培养,检验有机硅季铵盐是否具有长效抗菌性.结果 不同处理浓度对白假丝酵母菌生长有影响;不同处理时间对白假丝酵母菌生长无影响;处理浓度和处理时间两因素之间存在交互作用.1％的有机硅季铵盐浸泡纯钛即可使其产生抗菌性,浸泡120 min抗菌效果最佳.冷热循环5 000次后纯钛仍具有抗菌性;10 000次后无抗菌性.结论 有机硅季铵盐溶液浸泡纯钛,对白假丝酵母菌生长具有抑制作用,可使纯钛具有长效抗菌性能.     

大蒜素标准品DATS体外抗粪肠球菌生物膜作用的研究

目的:探讨不同浓度大蒜素对照品二烯丙基化三硫(dially trisulfide,DATS)体外对粪肠球菌生物膜的作用。方法:体外培养形成粪肠球菌生物膜,分别经1280、2560、5120 mg/L浓度的DATS作用后,采用MTT法观察DATS对生物膜粪肠球菌的抑菌率。结果:1280 mg/L DATS对对数期和饥饿期的生物膜粪肠球菌抑菌率约71%,显著高于对稳定期生物膜粪肠球菌的抑菌率58%,差异具有统计学意义(P<0.05),随着药物浓度的增高,抑菌率增高。结论:DATS对生物膜中的粪肠球菌具有明显杀灭或抑制作用。     

三种无机纳米抗菌剂对粪肠球菌的抗菌作用

目的:研究纳米银、载银纳米二氧化钛、掺氮纳米二氧化钛对粪肠球菌的抗菌作用。方法:将粪肠球菌在MBECTMP&G Assay中培养24 h,构建粪肠球菌感染模型,扫描电镜观察MBECTMP&G Assay上粪肠球菌感染情况。应用MBECTMP&G Assay以连续稀释法检测纳米银、载银纳米二氧化钛、掺氮纳米二氧化钛的最小抑菌浓度(MIC)和最小生物膜清除浓度(MBEC)。结果:扫描电镜下见粪肠球菌在MBECTM P&G Assay上形成生物膜。纳米银对粪肠球菌的MIC和MBEC分别为62.5 mg/L和1 000 mg/L,载银纳米二氧化钛MIC为64 g/L,但在所用浓度范围内均不能清除生物膜细菌,即未测得MBEC;掺氮纳米二氧化钛的MIC、MBEC均未测得;次氯酸钠的MIC和MBEC分别为6.56 g/L和13.13 g/L。结论:纳米银对粪肠球菌有较强抗菌作用,能清除粪肠球菌生物膜;粪肠球菌对载银纳米二氧化钛和掺氮纳米二氧化钛有较强抵抗力。     

次氯酸钠对粪肠球菌杀菌效果的体外研究

目的体外评价次氯酸钠(NaOCl)对粪肠球菌的杀菌效果及浓度依赖关系。方法采用纸片扩散法药敏实验观察NaOCl对粪肠球菌的抑菌环大小(mm),直接接触法观察NaOCl对粪肠球菌的灭活时间。结果5.25%NaOCl的抑菌环直径最大,4.00%与2.50%、1.00%与0.50%差异无显著性。5.25%NaOCl在30s内可杀死全部粪肠球菌,2.50%NaOCl杀死粪肠球菌需要15min,随浓度的下降,杀死细菌所需要的时间延长。结论高浓度NaOCl的效果优于低浓度NaOCl,2.50%NaOCl基本可满足临床要求。     

白假丝酵母菌与婴幼儿龋相关性的初步探讨

目的 初步探讨白假丝酵母菌与婴幼儿龋(ECC)的相关性.方法 采用分层整群抽样的方式随机选择广州市区及城郊447名3 ～ 5岁健康儿童作为研究对象,将其分为ECC组(n ＝ 238)和无龋组(n ＝ 209).采集龋坏组织样本及无龋牙的龈上菌斑共363份,应用科玛嘉培养基、芽管试验进行检测、鉴定,并运用卡方检验对比分析ECC组与无龋组、市区和城郊组间白假丝酵母菌检出情况;建立Logistic回归方程分析患龋情况与白假丝酵母菌检出率的相关性.结果 ECC组和无龋组中白假丝酵母菌检出率分别为44.1%和19.2%(χ2＝22.213,P < 0.001).ECC组中,患龋率高的城郊组白假丝酵母菌检出率(79.7%)高于市区组(28.0%)(χ2＝55.242,P < 0.001).经Logistic回归分析,龋失补牙面数每增加2.129个,白假丝酵母菌检出机率会相应增加0.104(P < 0.001).结论 白假丝酵母菌与婴幼儿龋的发生密切相关,可能为婴幼儿龋发生过程中的重要致龋菌之一.     

Susceptibility of Candida albicans and Enterococcus faecalis to Chitosan,Chlorhexidine gluconate and their combination in vitro

The aim of the present study was to analyse the sustain release of Chlorhexidine with Chitosan and to investigate the antimicrobial activity of 2% Chlorhexidine gel, 2% Chitosan gel and their combination against Candida albicans and Enterococcus faecalis. Sustain release of Chlorhexidine with Chitosan was determined using UV spectrophotometer. Then the inoculae of these organisms were used to make the lawn culture on sabouraud's dextrose agar and blood agar plates. Wells were prepared in these lawn cultures and filled with 2% Chlorhexidine gel, 2% Chitosan gel and their combination. The agar plates were incubated overnight at 37°C and the zone of inhibition was examined after 48 h. Release of Chlorhexidine with Chitosan was better than plain Chlorhexidine release. Combination of Chlorhexidine and Chitosan showed maximum inhibitory zone for C. albicans (25.2 mm) and E. faecalis (26.0 mm). Plain Chlorhexidine gel showed intermediate inhibitory zone for C. albicans (20.6 mm) and E. faecalis (21.4 mm) and plain Chitosan gel showed minimum inhibitory zone for C. albicans (16.6 mm) and E. faecalis (11.0 mm). Carbopol which served as control did not have any antimicrobial effect. The present study suggests that 2% Chlorhexidine gel in combination with 2% Chitosan gel has the highest antimicrobial effect against C. albicans and E. faecalis compared with 2% Chlorhexidine gel or 2% Chitosan gel alone.     

Antimicrobial activity of varying concentrations of sodium hypochlorite on the endodontic microorganisms Actinomyces israelii, A. naeslundii, Candida albicans and Enterococcus faecalis

AIM: To determine the resistance of microorganisms associated with refractory endodontic infections to sodium hypochlorite used as a root canal irrigant. METHODOLOGY: Two strains each of Actinomyces naeslundii, Candida albicans and Enterococcus faecalis were tested as late logarithmic phase inocula, against sodium hypochlorite adjusted to 0.5, 1.0, 2.5 and 5.25% w/v. Contact times used were 0, 10, 20, 30, 60 and 120 s. In the case of E. faecalis, additional experiments used contact times of 1.0, 2.0, 5.0, 10.0 and 30.0 min. Anti-microbial action was halted by sodium thiosulphate addition. Survivors were measured primarily using viable counts on drop plates. Additionally, pour plates were used to count low colony-forming units (cfu) and dilutions to 10(-6) were used to count high cfu. RESULTS: All concentrations of NaOCl lowered cfu below the limit of detection after 10 s in the case of A. naeslundii and C. albicans. However, E. faecalis proved to be more resistant to NaOCl. Using 0.5% NaOCl for 30 min reduced cfu to zero for both strains tested. This compares with 10 min for 1.0%, 5 min for 2.5% and 2 min for 5.25% (P < 0.001). Regression analysis for the dependent variable log(e)(count + 1) with log(e)(time + 1) and concentration as explanatory variables gave rise to a significant interaction between time and concentration (P < 0.001). CONCLUSION: The published association of E. faecalis with refractory endodontic infection may result, at least partially, from high resistance of this species to NaOCl. This does not appear to be the case with A. naeslundii or C. albicans.     

维吾尔族高龋儿童口腔中白色念珠菌基因分型研究

目的：研究乌鲁木齐市维吾尔族儿童口腔白色念珠菌的分布及高龋儿童口腔白色念珠菌基因分型。方法：利用科玛嘉念珠菌显色培养基对144名维吾尔族3～5岁儿童进行口腔白色念珠菌分离培养及鉴定,进行 PCR25SrDNA 基因分型。结果：35个儿童（24．3％）的口腔中检出白色念球菌。无龋、有龋、高龋儿童口腔白色念珠菌检出率分别为3．8％、50．0％和35．7％（χ2＝22．246,P ＝0．000）;25例高龋儿童的 PCR25rDNA 分3型,以 A 型为主（72．0％）。结论：白色念珠菌可能是维吾尔族儿童龋病的危险因素,白色念珠菌 PCR25SrDNA 基因的 A 型者可能更易致龋。     

根管冲洗液对粪肠球菌作用的研究进展

粪肠球菌是一种最常见的导致根管治疗失败的细菌,如何控制根管内的粪肠球菌是研究的热点。根管冲洗剂是杀灭和抑制粪肠球菌的有效方法之一,本文就根管内粪肠球菌的感染特点、常用根管冲洗液以及冲洗剂联合使用对其的作用等方面作一综述。     

饥饿状态的粪肠球菌的研究进展

作为顽固性或继发性根管内感染的主要致病菌,粪肠球菌可以饥饿状态在恶劣的环境中长期生存。在饥饿状态下,粪肠球菌可保持较低的代谢水平并形成生物膜,从而提高其对外界刺激的耐受水平。本文就饥饿状态与活的不可培养状态,饥饿状态下的粪肠球菌的生长状况,饥饿状态下的粪肠球菌的生物膜形成能力,饥饿状态下的粪肠球菌对外界刺激的耐受水平等研究进展作一综述。     

PIPS联合纳米银对根管粪肠球菌抗菌效果研究

目的 探究激光引发光声流系统(PIPS)和纳米银(AgNPs)联合使用对根管内粪肠球菌生物膜的抗菌效果。方法 收集36颗单根管离体牙,建立粪肠球菌感染根管实验模型,将样本随机分成6组,采用0.9%NaCl、2%NaClO、0.1%AgNPs溶液分别联合传统手动冲洗(CNI)或PIPS对根管进行冲洗,使用菌落计数法测定治疗前后根管内粪肠球菌生物膜菌落数,并计算菌落计数减少的百分比。结果 所有实验组粪肠球菌生物膜的抑制效果均强于对照组(P<0.05),使用PIPS辅助0.9%NaCl、2%NaClO、0.1%AgNPs冲洗组的降幅均分别大于CNI辅助0.9%NaCl、2%NaClO、0.1%AgNPs冲洗组(P<0.05)。PIPS辅助0.1%AgNPs冲洗组的降幅明显大于PIPS辅助2%NaClO冲洗组(P<0.05)。结论 PIPS辅助AgNPs溶液冲洗可以显著提高根管内粪肠球菌生物膜的清除效果。     

An in vitro evaluation of the ability of ozone to kill a strain of Enterococcus faecalis

AIM: To evaluate the potential of ozone as an antibacterial agent using Enterococcus faecalis as the test species. METHODOLOGY: Ozone was produced by a custom-made bench top generator and its solubility in water determined by ultraviolet (258 nm) spectrophotometric analysis of solutions through which ozone was sparged for various time-periods. The antibacterial efficacy of ozone was tested against both broth and biofilm cultures. Ozone was sparged for 30, 60, 120 and 240 s, through overnight broth cultures of a strain of E. faecalis (E78.2) and compared with those that were centrifuged, washed and resuspended in water. Enterococcus faecalis (E78.2) biofilms were grown on cellulose nitrate membrane filters for 48 h and suspended in water through which ozone gas was sparged with stirring for 60, 120 and 240 s in a standard fashion. In a separate test, biofilms were also exposed to gaseous ozone. Sodium hypochlorite (NaOCl) was used as a positive control. All experiments were repeated four times. RESULTS: There were significant (P < 0.05) reductions of bacteria in the unwashed (2 log(10) reductions) and washed (5 log(10) reductions) broth cultures following 240 s applications. Biofilms incubated for 240 s with ozonated water showed no significant reduction in cell viability attributable to ozone alone, whereas with NaOCl no viable cells were detected over the same time. Gaseous ozone applied for 300 s had no effect on these biofilms. CONCLUSIONS: Ozone had an antibacterial effect on planktonic E. faecalis cells and those suspended in fluid, but little effect when embedded in biofilms. Its antibacterial efficacy was not comparable with that of NaOCl under the test conditions used.