基于重水拉曼技术的白色念珠菌对变异链球菌代谢活性和耐药性影响的研究

目的 评价氟化钠(NaF)对变异链球菌的抑菌效能;白色念珠菌代谢产物对变异链球菌代谢活性和NaF作用下的耐药性影响.方法 分别采用肉汤稀释法和重水拉曼技术,参考最低抑菌浓度(MIC)及最小代谢活性抑制浓度(MIC-MA)指标,评价NaF对变异链球菌生长及代谢的抑制效果;采用重水拉曼技术,检测不同浓度白色念珠菌上清液对变...     

基于重水拉曼技术评价次氯酸钠对粪肠球菌抑菌效能的研究

目的 系统评价重水拉曼技术在耐药性研究领域的可行性及次氯酸钠对粪肠球菌的抑菌效能.方法 1)采用吸光度测定、重水拉曼技术评价粪肠球菌在不同浓度重水中生长状态及对重水的吸收规律,评价重水拉曼技术在细菌耐药性研究方面的普适性.2)采用肉汤稀释法,结合吸光度测定次氯酸钠对粪肠球菌的最小抑菌浓度(MIC);采用重水拉曼技术测定...     

基于重水拉曼技术评价口腔抑菌剂对粪肠球菌抑菌效能的研究

目的:开发有效且对患者副作用小的口腔抑菌剂配方,系统评价过氧化氢(hydrogen peroxide,H2O2)、次氯酸钠(Sodium hypochlorite,NaClO)对粪肠球菌(Enterococcus faecalis ATCC29212)的抑菌效能.方法:分别采用肉汤稀释法和重水拉曼技术(D2O-labeled single-cell Raman micro-spectroscopy),通过最小抑菌浓度(minimum inhibitory concentration,MIC)和最低抑制代谢浓度(minimum inhibitory concentration based on metabolic activity,MIC-MA)定量评价了抑菌剂对粪肠球菌的生长和代谢抑制作用.结果:对于过氧化氢和次氯酸钠,MIC分别为110 mg/L和0.45 g/L,尽管生长完全停止,但细菌细胞的代谢活性在8 h平均降低了71％、70％,显示出一种"非生长但代谢活跃"(NGMA)的状态,这种状态可能导致潜在的难治性反复感染.而MIC-MA分别为220 mg/L和0.9 g/L时,所有细胞的代谢活动在暴露8 h后完全停止.此外,NaClO+H2O2的组合使用优于单独使用次氯酸钠、过氧化氢.结论:MIC-MA有利于严格评估抗细菌疗效,NaClO+H2O2可作为细菌病原体更有效的抑菌剂方案.     

白鲜碱对白色念珠菌体外抑制作用初探

目的：检测白鲜碱对白色念珠菌的抑制作用,及其对白色念珠菌细胞周期的影响。方法：采用白色念珠菌标准菌株（ATCC76615）为研究对象,用经典方法测定白鲜碱对白色念珠菌的最小抑菌浓度（MIC）,抑制生物膜50%（SMIC50）的药物浓度,流式细胞仪分析白鲜碱对白色念珠菌细胞周期的影响。结果：白鲜碱对白色念珠菌的MIC为312.5μg/mL,对生物膜的SMIC50为1250μg/mL,白鲜碱能使白色念珠菌生长停滞。结论：白鲜碱具有抑制白色念珠菌生长的能力。     

4种维药体外抗白色念珠菌的活性测定

目的:观察没食子、桑白皮、石榴皮、月季花4种维药体外对白色念珠菌的抑制作用,并对4种药物的抑菌和杀菌效果进行评价。方法:采用常量肉汤稀释法(浓度为1000g/L),检测没食子、桑白皮、石榴皮、月季花4种药物的抑菌和杀菌效果。结果:没食子提取液对白色念珠菌的最低抑菌浓度(MIC)为25g/L,杀菌浓度(MBC)为50g/L;石榴皮浸液对白色念珠菌MIC为125g/L,MBC为250g/L;月季花浸液对白色念珠菌MIC为125g/L,MBC为500g/L,桑白皮浸液对白色念珠菌无抑、杀菌作用。结论:没食子、石榴皮、月季花提取液在体外均具有一定的抗白色念珠菌活性作用,桑白皮浸液在体外对白色念珠菌无抑、杀菌作用。     

西帕依固龈液和没食子体外抗白色念珠菌的活性测定

目的：体外观察西帕依固龈液和没食子对白色念珠菌的作用,并对二者的抑菌和杀菌效果进行评价。方法：采用常量肉汤稀释法,检测西帕依固龈液和没食子的抑菌和杀菌效果。结果：西帕依固龈液对白色念珠菌的最低抑菌浓度（MIC）为5mg/ml,最低杀菌浓度（MBC）为10mg/ml;没食子提取液对白色念珠菌的最低抑菌浓度（MIC）为25mg/ml,杀菌浓度（MBC）为50mg/ml。结论：没食子提取液和西帕依固龈液在体外均具有一定的抗白色念珠菌活性。     

五白汤组分体外抗白色念珠菌活性筛选

目的：筛选五白汤组分中具有抗白色念珠菌活性的药物。方法：采用白色念珠菌标准菌株（ATCC76615）为研究对象,应用煎煮法及水提醇沉淀法分别对五白汤各组成药物进行制备,参照NCCLS M27-A2推荐的方法测定五白汤各组成药物对白色念珠菌的最小抑菌浓度（MIC）。结果：白鲜皮水煎剂、苦参水煎剂和苦参醇提液对白色念珠菌的MIC分别为62.5 mg/mL、15.625 mg/mL、62.5 mg/mL。结论：白鲜皮水煎剂、苦参水煎剂以及苦参醇提液具有抗白色念珠菌活性。     

氟康唑对HIV感染者口腔白色念珠菌抗真菌后效应的体外研究

目的 评估氟康唑体外最小抑菌浓度(minimum inhibitory concentration,MIC)和检测暴露于小剂量氟康唑后白色念珠菌口腔分离株的抗真菌后效应(post-antifungal effect,PAFE).方法 将白色念珠菌标准株和10株临床分离株分别暴露于4×MIC和6×MIC的氟康唑后,使用自...     

氟康唑对HIV感染者口腔白色念珠茵抗真菌后效应的体外研究

目的评估氟康唑体外最小抑菌浓度（minimum inhibitory concentration,MIC）和检测暴露于小剂量氟康唑后白色念珠菌口腔分离株的抗真菌后效应（post—antifungal effect,PAFE）。方法将白色念珠菌标准株和10株临床分离株分别暴露于4×MIC和6×MIC的氟康唑后,使用自动化的浊度分析测撮法检测白色念珠菌PAFE的存在。结果由4×MIC和6×MIC的氟康唑在RPMI1640液体培养基巾诱导的白色念珠菌标准株产生的PAFE平均持续时问分别为0．12h和3．14h;诱导的10株临床分离株产生的PAFE持续时间平均分别为（0．19±0．24）h和（2．08±0．25）h。其中6×MIC氟康哗的PAFE在临床菌株内差异有统计学意义（P=0．000）,而×MIC氟康唑的PAFE在临床菌株内差异没有统计学意义（P=0．529）。结论氟康唑能有效地抑制白色念珠菌的生长,在白色念珠菌中引起PAFE。     

苦参碱对白色念珠菌生物膜的体外抑制作用

目的:建立白色念珠菌生物膜体外模型,观察中药有效成分苦参碱对生物膜活性及超微结构的影响。方法:以白色念珠菌国际标准菌株ATCC76615为研究对象,采用96孔微量培养皿,甲基四氮盐(XTT)减低的方法,评价苦参碱对不同阶段白色念珠菌生物膜的体外生长动力学影响;应用激光共聚焦显微镜和死菌/活菌荧光染色方法观察苦参碱对白色念珠菌生物膜超微结构的影响。结果:苦参碱对不同生长阶段(早、中、成熟期)的白色念珠菌生物膜均有抑制作用,随着生物膜成熟度的增加,耐药性增强;激光共聚焦扫描显微镜死菌/活菌荧光染色观察发现,苦参碱可影响白色念珠菌生物膜中细胞的形态及代谢状态。结论:苦参碱对体外白色念珠菌生物膜具有抑制作用。     

Control of microorganisms in vitro by endodontic irrigants

The aim of this study was to determine the minimum inhibitory concentration (MIC) and antimicrobial effectiveness by the direct exposure test of 4 endodontic irrigants [1% sodium hypochlorite (NaOCl), 2% chlorhexidine (CHX), 1% calcium hydroxide (Ca(OH)2; prepared with 1 g of Ca(OH)2 and 100 mL of sterile distilled water), a solution of Ca(OH)2 + detergent (HCT20)] for S. aureus, E. faecalis, P. aeruginosa, B. subtilis, C. albicans and a mixed culture. Microbial growth was analyzed by two methods: turbidity of the culture medium that was confirmed by Gram stain and subculture in a specific nutrient broth. In the dilution test, NaOCl solution showed MIC equal to 0.1% for S. aureus, E. faecalis, P. aeruginosa and C. albicans and equal to 1% for B. subtilis and the mixed culture. CHX (2%) presented MIC equal to 0.000002% for S. aureus, 0.02% for E. faecalis, B. subtilis, C. albicans and the mixed culture and 0.002% for P. aeruginosa. Ca(OH)2 solution (1%) showed MIC greater than 1% for all the microorganisms except P. aeruginosa for which it was equal to 1%. Calcium hydroxide solution + detergent showed MIC equal to 4.5 mL for S. aureus, P. aeruginosa, B. subtilis, C. albicans and the mixed culture and greater than 4.5 mL for E. faecalis. In the direct exposure test, NaOCl had better antimicrobial effectiveness for all microorganisms at all times. CHX (2%) was effective for S. aureus, E. faecalis and C. albicans at all times, and ineffective for P. aeruginosa, B. subtilis and the mixed culture. The other solutions showed the worst results.     

Oral Candida albicans in bone marrow transplant patients given chlorhexidine rinses: occurrence and susceptibilities to the agent

The tongue and buccal mucosa of 26 bone marrow transplant recipients given three 0.12% chlorhexidine digluconate (CHX) oral rinses daily for 8 weeks were sampled weekly for oral Candida albicans. Putative C. albicans colony-forming units on selective bismuth sulfite glucose glycine yeast agar plates were identified with the API 20C system. The CHX minimum inhibitory concentrations (MICs) of oral C. albicans isolates obtained at all 8 sample weeks was determined with a microbroth dilution sensitivity assay. The CHX MIC range for yeast isolates selected randomly at all sample weeks was up to 2.5 to up to 20 micrograms/ml (mean MIC less than or equal to 8.5 micrograms/ml). The CHX MIC range for isolates at week 1 was less than or equal to 5 to less than or equal to 10 micrograms/ml (mean MIC less than or equal to 7.9 micrograms/ml) compared with less than or equal to 2.5 to less than or equal to 20 micrograms/ml at week 8 (mean MIC less than or equal to 8.8 micrograms/ml). Therefore the persistence of oral C. albicans in bone marrow transplant recipients using CHX rinses was due neither to low CHX susceptibilities nor to the development of resistance to the agent.     

In vitro antimicrobial activity of phytotherapic Uncaria tomentosa against endodontic pathogens

The aim of this study was to evaluate the antimicrobial activity of Uncaria tomentosa (Willd.) DC (cat's claw) against Enterococcus faecalis, Staphylococcus aureus, and Candida albicans. Suspensions with 10(8) cells/ml of each microorganism were plated in triplicate on Mueller-Hinton agar. Wells in the agar were made and filled with 2% chlorhexidine (CHX) gel, 2% cat's claw (CC) gel, 2% CHX+CC, and 1% hydroxyethylcellulose (NAT) gel. Inhibition halos were measured after 24 h at 37°C and differences were analyzed using one-way ANOVA. The mean diameter of the microbial growth inhibition zones of 2% CHX+CC against the tested microbial strains ranged from 21.7 to 33.5 mm. This was the most effective substance against E. faecalis and C. albicans, followed by CHX and CC. Against S. aureus, CHX+CC, CHX, and CC showed similar antimicrobial activity (P > 0.05). The results indicate that all the investigated compounds had antimicrobial activity against microorganisms frequently found in infected root-filled teeth.     

纳米载银树脂基托的体外抗菌效果

目的研究纳米载银树脂基托在体外对变形链球菌和白色念珠菌的抗菌效果。方法先测定纳米载银抗菌剂对变形链球菌和白色念珠菌的最小抑菌浓度,并以此为依据在聚甲基丙烯酸甲酯基托树脂粉中添加不同比例的抗菌剂,制成抗菌树脂基托,用贴膜法测定该树脂基托对变形链球菌和白色念珠菌的抗菌率。结果纳米载银抗菌剂对变形链球菌的最小抑菌浓度为0.1mg/ml,对白色念珠菌的最小抑菌浓度为1mg/ml。当添加抗菌剂的浓度分别为1、2、5、10mg/ml时,树脂基托对变形链球菌的抗菌率分别为67.4%、71.3%、99.0%、99.5%;对白色念珠菌的抗菌率分别为25.8%、54.8%、90.3%、93.0%。结论载银抗菌树脂基托在体外表现了一定的抗变形链球菌和抗白色念珠菌的效果,当树脂基托中抗菌剂的浓度达到5mg/ml时,抗菌效果满意。     

Catechin-incorporated dental copolymers inhibit growth of Streptococcus mutans

Objective:

To test the inhibitory growth activity of green tea catechin incorporated into dental resins compared to resins containing the broad-spectrum antimicrobial compound chlorhexidine against Streptococcus mutans in vitro.

Material and Methods:

The minimum inhibitory concentrations (MICs) of epigallocatechin-gallate (EGCg) and chlorhexidine (CHX) were determined according to the microdilution method. Resin discs (5 mm x 3 mm) were prepared from Bis-GMA/TEGDMA (R1) and Bis-GMA/CH₃Bis-GMA (R2) comonomers (n=9) containing: a) no drug, b) EGCg, c) CHX. Two concentrations of each drug (0.5x MIC and 1x MIC) were incorporated into the resin discs. Samples were individually immersed in a bacterial culture and incubated for 24 h at 37º C under constant agitation. Cell viability was assessed by counting the number of colonies on replica agar plates. Statistical analysis was performed using one-way ANOVA, Tukey and Student t-tests (α=0.05).

Results:

Both resins containing EGCg and CHX showed a significant inhibition of bacterial growth at both concentrations tested (p<0.05). A significantly higher inhibition was observed in response to resins containing CHX at 0.5x MIC and 1x MIC, and EGCg at 1x MIC when compared to EGCg at 0.5x MIC. Also, EGCg at 0.5x MIC in R1 had a significantly higher growth inhibition than in R2.

Conclusions:

Both EGCg and CHX retained their antibacterial activity when incorporated into the resin matrix. EGCg at 1x MIC in R1 and R2 resins significantly reduced S. mutans survival at a level similar to CHX. The data generated from this study will provide advances in the field of bioactive dental materials with the potential of improving the lifespan of resin-based restorations.     

The antimicrobial and antibiofilm properties of allicin against Candida albicans and Staphylococcus aureus – A therapeutic potential for denture stomatitis

The objective of this study is to determine the therapeutic efficacy of allicin against Candida albicans (C. albicans) and Staphylococcus aureus (S. aureus), the common etiological agents for denture stomatitis (DS). The minimum inhibitory concentration (MICs), minimum bactericidal concentrations (MBCs) and minimum fungicidal concentration (MFCs) of allicin were determined by the broth microdilution method followed by checkerboard microdilution method for a synergistic interaction between allicin + nystatin and allicin + CHX. The potential of allicin to eradicate C. albicans and S. aureus biofilms was assessed by treating biofilm formed on self- polymerized acrylic resin with allicin at a sub-MIC concentration for 5 min. The commercial denture cleanser (brand X) was used as a positive control. A Kruskal-Wallis test followed by the post-hoc Mann-Whitney U test was applied (SPSS 20.0), and the level of significance was set at P < 0.05. Allicin exhibited antimicrobial activity against C. albicans (MIC:8 µg/ml and MFC:16 µg/ml) and S. aureus (MIC:8 µg/ml and MBC:8 µg/ml). A synergistic interaction was observed between allicin + nystatin and allicin + CHX (FICI ≤ 0.5). Allicin exhibited significant biofilm eradication against C. albicans and S. aureus biofilms with percentages of 50.0% and 52.6%, respectively. The results of this study suggest a possible application of allicin in treating C. albicans and S. aureus infection in DS.     

Effectiveness of intracanal irrigants and medications against the yeast Candida albicans

An in vitro study was conducted to determine the susceptibility of the yeast Candida albicans to various intracanal irrigants and medications. The minimum inhibitory concentration (MIC) of sodium hypochlorite, hydrogen peroxide, chlorhexidine digluconate, and aqueous calcium hydroxide that is required to kill a standardized inoculum of C. albicans was determined. Growth of the yeast was measured by optical density. Sodium hypochlorite, hydrogen peroxide, and chlorhexidine digluconate were effective anticandidal agents with MICs of <10 microgram/ml, 234 microgram/ml, and <0.63 microgram/ml, respectively. Aqueous calcium hydroxide had no activity. A standardized inoculum of C. albicans cells was also placed in direct contact with either calcium hydroxide paste or camphorated para-monochlorophenol (CPMC), and candidal growth was assessed by colony counts on Sabouraud's dextrose agar. Calcium hydroxide paste and CPMC, when maintained in direct contact with C. albicans, were effective antifungal agents.     

Antimicrobial Effect of Conventional Root Canal Medicaments vs Propolis against Enterococcus faecalis, Staphylococcus aureus and Candida albicans

Aim: To evaluate and compare antimicrobial effect of various root canal medicaments against Enterococcus faecalis, Staphylococcus aureus and Candida albicans. Materials and methods: Six root canal medicaments: 2% sodium hypochlorite (NaOCl), 2% chlorhexidine (CHX) Calcium hydroxide (Ca(OH)2), EDTA, MTAD and propolis and three microorganisms: Staphylococcus aureus, Enterococcus faecalis and Candida albicans were used. These strains were inoculated in brain heart infusion (BHI) and incubated at 37 degrees C for 24 hours. For the agar diffusion test (ADT), petri plates with 20 ml of BHI agar were inoculated with 0.1 ml of the microbial suspensions, using sterile swabs that were spread on the medium, obtaining growth injunction. Paper disks were immersed in the experimental solutions for 1 minute. Subsequently, four papers disks containing one of the substances were placed on the BHI agar surface in each agar plate. The plates were incubated at 37°C for 48 hours. The diameter of microbial inhibition was measured around the papers disks containing the substances. One way ANOVA followed by Tukey's post-hoc test were used. p-value >0.05 was considered statistically significant. Results: Propolis and other irrigants were found to be effective on C. albicans, S. aureus and E. faecalis. CHX and MTAD were found to be most effective amongst all the materials tested followed by propolis. Conclusion: Propolis showed antimicrobial activity against E. faecalis, S. aureus, C. albicans. It appears that propolis is an effective intracanal irrigant in eradicating E. faecalis and C. albicans. Clinical significance: Propolis is an effective intracanal irrigant in eradicating E. faecalis and C. albicans. It could be used as an alternative intracanal medicament. Keywords: Root canal medicaments, Enterococcus faecalis, Staphylococcus aureus, Candida albicans, Propolis. How to cite this article: Mattigatti S, Jain D, Ratnakar P, Moturi S, Varma S, Rairam S. Antimicrobial Effect of Conventional Root Canal Medicaments vs Propolis Against Enterococcus faecalis, Staphylococcus aureus and Candida albicans. J Contemp Dent Pract 2012;13(3):305-309. Source of support: Nil Conflict of interest: None declared.