白色念珠菌经口感染ICR小鼠建立系统性感染模型

目的探究白色念珠菌(C.albicans)经口感染ICR小鼠建立系统性感染模型,观察C.albicans经黏膜感染后在小鼠体内组织增殖及分布规律。方法 46只ICR雄性小鼠随机分为模型组A(n=20)、模型组B(n=20)、对照组(n=6)。模型组采用棉签法口腔接种C.albicans(7×106cfu/m L),对照组同方法接种等容积生理盐水。模型组A小鼠用于临床、生存、剖检观察试验;模型组B接种后第3、5、7天随机解剖5只小鼠用于组织载菌量和病理检验(对照组每个时间点解剖2只),活菌平板计数法检测小鼠组织载菌量,光镜观察小鼠舌、胃、肝、肾病理组织学变化。结果模型组小鼠接种后第3天舌面出现明显白斑并随时间加重引起死亡,第5天小鼠死亡率超过50%,第7天死亡率达100%,并能从舌(87.5%)、胃(87.5%)及内脏组织肝(54.5%)、肾(50.5%)、肺(20%)和心脏(4%)中分离到C.albicans,显微镜观察在舌、食道、胃、肝、肾存在菌丝的增殖,对照组未见C.albicans生长,提示模型组小鼠因C.albicans黏膜感染引起小鼠播散性的系统性感染。结论 C.albicans可在一定条件下突破黏膜免疫屏障引起小鼠机会性系统性感染,从而加重感染死亡。     

白假丝酵母激活的巨噬细胞自噬 促进MHCⅡ抗原提呈

目的探究白假丝酵母(Candida albicans)激活的Raw264.7细胞自噬在主要组织相容性复合体Ⅱ类分子(MHCⅡ)抗原提呈以及协同刺激分子表达中的作用。方法 C.albicans刺激Dectin-1单克隆抗体封闭或白皮杉醇阻断的Raw264.7细胞,Western blot法检测LC3Ⅱ表达量,RT-PCR检测CD80与CD86的表达。免疫荧光实验观察有无3-MA预处理的GFP-LC3-Raw264.7细胞与C.albicans共孵育后MHCⅡ与LC3在胞浆的分布,ELISA法检测有无封闭Dectin-1或3-MA预处理的Raw264.7细胞与C.albicans共孵育不同时间段后IL-6的分泌。结果阻断Dectin-1或Sky后C.albicans诱导的LC3Ⅱ表达降低。LC3、MHCⅡ与胞内C.albicans存在显著的共定位关系,阻断自噬后C.albicans与MHCⅡ的共定位明显减弱。C.albicans引发Raw264.7细胞表达CD80与CD86mRNA,封闭Dectin-1或阻断自噬后二者转录水平降低。C.albicans通过Dectin-1引发Raw264.7细胞分泌IL-6,阻断自噬对IL-6分泌无显著影响。结论 C.albicans通过Dectin-1/Sky通路激活巨噬细胞自噬,自噬体的构建促进MHCⅡ招募至胞内C.albicans,并促进协同刺激分子的表达。     

粉防己碱对白念珠菌生物膜及芽管形成的影响

目的研究粉防己碱(Tet)对白念珠菌(Candida albicans)生物膜及芽管形成的影响。方法采用XTT还原比色法观察Tet对C.albicans成膜的影响;将0.01、0.1、1μmol/L的Tet分别与C.albicans悬液共同孵育,显微镜下计数芽管形成率。分别设阳性对照组(两性霉素B与白念珠菌悬液共孵育)和阴性对照组(白念珠菌悬液中不加Tet),试验重复5次。结果 Tet各剂量组对C.albicans生物膜及芽管形成具有明显抑制作用(P0.05),其作用与药物浓度呈正相关,其中1μmol/L的Tet对C.albicans生物膜及芽管形成的抑制率最高,C.albicans生物膜及芽管形成率低于阴性对照组(P0.05),1μmol/L的Tet组生物膜及芽管形成率低于0.01及0.1μmol/L组(P0.05)。与阳性对照组比较,差异无统计学意义(P0.05)。结论 Tet对体外C.albicans生物膜及芽管形成有一定的抑制作用。     

DKP对3株病原菌生物膜的抑制作用研究

生物膜的存在使一些由病原菌引发的疾病变得更加难以治疗。经研究发现一种环二肽物质DKP——cyclo(Pro-Phe)能够抑制这3株病原菌(Staphylococcus aureus,Pseudomonas aeruginosa,Candida albicans)生物膜的形成。通过对不同浓度DKP作用下所形成的生物膜进行结晶紫定量、菌落计数分析和结构显微分析表明:在DKP的浓度达到10 mg/ml时,S. aureus和P. aeruginosa的生物膜几乎消失;在DKP的浓度达到12 mg/ml时,C. albicans的生物膜被显著抑制。这一发现为寻找新型的生物膜抑制剂治愈顽固疾病带来了新的希望。     

294株白念珠菌药物敏感试验及耐药性分析

近年来,随着临床使用大量抗生素、免疫抑制剂和糖皮质激素治疗严重感染、肿瘤及自身免疫病,人体菌群失调和真菌感染发生率持续升高.同时,抗真菌药物的频繁应用亦造成真菌耐药性日益增多,真菌感染成为医院感染的主要病原体之一.真菌感染中以白念珠菌（Candida albicans）比例最高,本文对本院2012年1～12月送检的临床标本常规培养分离,共分离的白念珠菌294株,其药物敏感试验及耐药性分析如下.     

Terric acid对白色假丝酵母生长、细胞形态和大分子合成影响的研究

从海洋霉菌Aspergillus flavis No.179中分离纯化胞外抗真菌代谢产物Terric acid。以液体稀释法研究Terricacid在不同浓度下对酵母类真菌白色假丝酵母(Candida albicans)生长、细胞形态的影响。结果表明,Terric acid在较低浓度下能抑制测试菌株C.albicans AS2,538的生长,高浓度的Terric acid则能杀死C.albicans AS2,538细胞,其最小抑菌浓度和最小杀菌浓度分别为6.25μg/mL和50μg/mL。在亚抑菌浓度下,该物质能抑制C.albicans AS2,538假菌丝的形成,并引起细胞形态发生改变。当浓度达到50μg/mL时,细胞形态变得极不规则,有些细胞体积增大或破裂溶解。用14C-缬氨酸1、4C-胸腺嘧啶3、H-尿嘧啶同位素标记物掺入的方法分别研究Terric acid对测试菌株C.albicans AS2,538蛋白质、DNA和RNA合成的影响,与对照相比,在含有5μg/mL Terric acid的培养基中培养4h后,14C-缬氨酸和1H-尿嘧啶的掺入量分别减少47.8%和70.7%,14C-胸腺嘧啶的掺入量没有明显差异。此结果暗示Terricacid能抑制测试菌C.albicans AS2,538蛋白质和RNA的合成,但对其DNA的合成没有明显影响。     

比较五种中草药牙膏对口腔常见菌的抗菌潜力

目的评价5种国产中草药牙膏对口腔常见菌的抗菌潜力。方法运用扩散法来评价5种国产中草药牙膏———美加净复合中草药牙膏(MAX)、洁银中药牙膏(JY)、田七特效中药牙膏(TQ)、中华中草药牙膏(ZH)、高露洁草本美白牙膏(Colgate H)对口腔常见菌:变形链球菌(S.mutants)、血链球菌(S.sanguis)、粘放线菌(A.viscosus)和白色念珠菌(C.albicans)的抗菌潜力。结果阴性对照组未见产生抗菌区域,而阳性对照组对4种口腔常见菌产生明显的抗菌区域。TQ对除了白色念珠菌(C.albicans)外的其他3种口腔常见菌都有明显的抗菌作用,其余4种牙膏在膏状和稀释状态下对所有4种常见菌均显示了明显和持续的抗菌作用。膏状状态下的抗菌区域比稀释状态下有显著的增大(P<0.05)。结论除TQ对C.albicans显示无效外,所有5种国产中草药牙膏对口腔内的常见菌均有明显的抗菌作用。     

Reg基因家族蛋白对胰岛β细胞生长的影响

Reg基因家族蛋白,属于C型凝集素超家族,具有相同的钙依赖性碳水化合物识别域,在损伤、感染、糖尿病及肿瘤中发生作用.近年来,已有18个Reg基因家族成员被克隆和鉴定.本文综述Reg基因家族蛋白的分类和基因表达调节,以及Reg基因家族蛋白对胰岛β细胞增殖与在自身免疫中的作用.Reg I和人胰岛再生相关蛋白(INGAP)在体外或体内参与胰腺的再生.在1型糖尿病发生中,Reg I和Reg II可做为自身抗原.尽管Reg基因蛋白的功能尚不清楚,但为1型糖尿病的治疗带来新的希望.     

白色念珠菌体外诱导氟康唑耐药性的实验研究（简报）

随着广谱抗生素的普遍应用以及免疫缺陷人群的增加,机会性致病菌念珠菌感染日益增多。深部念珠菌感染已经成为重症患者死亡的重要原因,白色念珠菌(C．albicans)是其中的主要致病菌。低毒广谱的唑类抗真菌药氟康唑是既能治疗严重真菌感染又不会产生明显副作用的少数抗真菌药之一,它的广泛使用取得良好治疗效果,但也导致菌株耐药率增加而使临床治疗失败。近10年来,在治疗     

土槿乙酸与氟康唑联合抗白念珠菌作用的研究

正白念珠菌(Candida albicans)是一种机会性致病酵母菌,作为侵袭性真菌感染最常见的致病菌,可在免疫功能低下的个体中引发致命感染[1]。唑类抗真菌药物中,特别是氟康唑, 由于其疗效好、毒性小,在临床治疗中应用最多。然而,伴随着氟康唑广泛应用于白念珠菌感染,使得白念珠菌耐药率问题显著增多,不利于疾病治疗[2]。在临床治疗中,新型抗真菌药物的研发总是滞后于耐药性的增加,有效的抗真菌药物相对较少。近年来,研究者通过使用药物联合来克服     

Cassia alata and the preclinical search for therapeutic agents for the treatment of opportunistic infections in AIDS patients.

In our search for therapeutic agents from natural sources with potential for the treatment of opportunistic infections in patients afflicted with acquired immunodeficiency syndrome (AIDS), we investigated antibacterial and antifungal activities of water extracts of Cassia alata (C. alata). The extracts are traditionally used in Ivory Coast, West Africa to treat bacterial infections caused by Escherichia coli (E. coli), and fungal infections caused by Candida albicans (C. albicans) and dermatophytes. Our working hypothesis was that the extract contains active ingredient(s) which can be isolated, identified and developed into useful antibacterial/antifungal agents for the treatment of opportunistic infections in patients with AIDS. We used the broth dilution and agar dilution methods. Specifically, we focused on E. coli and C. albicans and the effectiveness of the extracts was evaluated relative to those of standard antibacterial agent chloramphenicol and antifungal agent amphotericin B. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) for the water extract of C. alata against E. coli were 1.6 mg/ml and 60 mg/ml, respectively; corresponding data for chloramphenicol were 2 micrograms/ml and 10 micrograms/ml. Similarly, the MIC and minimum fungicidal concentration (MFC) for the extract against C. albicans were 0.39 mg/ml and 60 mg/ml in contrast to 0.58 micrograms/ml and 0.98 micrograms/ml for amphotericin B. From the dose-response curve plots, the extract had an IC50 of 31 mg/ml for E. coli and 28 mg/ml for C. albicans. The data suggest that C. alata extracts contain agent(s) which have therapeutic potential and might be useful if isolated and developed for the treatment of opportunistic infections of AIDS patients.     

Cassia alata and the preclinical search for therapeutic agents for the treatment of opportunistic infections in AIDS patients.

In our search for therapeutic agents from natural sources with potential for the treatment of opportunistic infections in patients afflicted with acquired immunodeficiency syndrome (AIDS), we investigated antibacterial and antifungal activities of water extracts of Cassia alata (C. alata). The extracts are traditionally used in Ivory Coast, West Africa to treat bacterial infections caused by Escherichia coli (E. coli), and fungal infections caused by Candida albicans (C. albicans) and dermatophytes. Our working hypothesis was that the extract contains active ingredient(s) which can be isolated, identified and developed into useful antimicrobial/antifungal agents for the treatment of opportunistic infections in patients with AIDS. We used the broth dilution and agar dilution methods. Specifically, we focused on E. coli and C. albicans and the effectiveness of the extracts was evaluated relative to those of standard antibacterial agent chloramphenicol and antifungal agent amphotericin B. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) for the water extract of C. alata against E. coli were 1.6 mg/ml and 60 mg/ml respectively; corresponding data for chloramphenicol were 2 ug/ml. Similarly, the MIC and minimum fungicidal concentration (MFC) for the extract against C. albicans were 0.39 mg/ml and 60 mg/ml in contrast to 0.58 ug/ml and 0.98 ug/ml for amphotericin B. From the dose-response curve plots, the extract had an IC50 of 31 mg/ml for E. coli and 28 mg/ml for C. albicans. The data suggest that C. alata extracts contain agent(s) which have therapeutic potential and might be useful if isolated and developed for the treatment of opportunistic infections of AIDS patients.     

呼吸内科患者白色念珠菌痰培养阳性的危险因素及耐药性变迁分析

目的分析呼吸内科患者白色念珠菌痰培养阳性的危险因素及对常用抗真菌药物的耐药性,为临床预防、早期诊断及有效治疗提供依据。方法对2007年1月至2009年12月浙江大学医学院附属第一医院呼吸内科白色念珠菌痰培养阳性患者的临床资料进行回顾性调查,统计其年龄分布、可能感染因素、基础疾病、被感染前抗菌药物的使用及近3年对抗真菌药物的耐药性变迁。结果呼吸内科白色念珠菌痰培养阳性的相关因素多,老年、气管插管/切开、机械通气、慢性阻塞性肺疾病及长期多种抗菌药物的使用患者中感染几率明显增高,且3年来,白色念珠菌的耐药性有所升高。结论临床上细心操作、抗菌药谨慎使用是目前减少白色念珠菌感染的重要途径。     

Production of anti-Candida antibodies in mice with gut colonization of Candida albicans

BACKGROUND: Production of antibodies that are specific for allergens is an important pathological process in inflammatory allergic diseases. These contain the antibodies against antigens of Candida albicans, one of the normal microbial flora in an intestinal tract. We studied the effects of the prednisolone administration on the production of anti-Candida antibodies in the gastrointestinally C. albicans-colonized mice. METHODS AND MATERIALS: BALB/c mice, treated with antibacterial antibiotics to decontaminate indigenous intestinal bacterial flora, were inoculated intragastrically with C. albicans. The mice, in which C. albicans grows intestinally, were administered prednisolone to induce temporary immunosuppression. The Candida growth in their intestinal tract and their antibody response to Candida were examined. RESULTS: Antibiotic treatment allowed establishment of C. albicans gastrointestinal colonization, but did not cause subsequent systemic dissemination of C. albicans in all the animals. When these animals received an additional treatment with prednisolone, they showed a significantly higher population of C. albicans in their feces than those of animals treated with antibiotics alone, and the organisms were recovered even from their kidney. This systemic dissemination by C. albicans appeared to be temporal, because all the mice survived without any symptoms for more than 2 months. Examination of the serum titers of total immunoglobulin (Ig)E antibodies and specific IgE and IgG antibodies against Candida antigens demonstrated that titers of total IgE increased, partially by day 14 and clearly at day 27, in prednisolone-treated Candida-colonized mice. Without prednisolone treatment, an increment of the serum titer was scarcely observed. By day 27, corresponding to the increase of total IgE, the anti-Candida IgE and IgG titer increased in mice of the prednisolone-treated group. CONCLUSION: Administration of prednisolone to Candida-colonized mice can induce production of the IgG, IgE antibodies against Candida antigens, perhaps through temporal systemic dissemination of Candida from the intestinal tract.     

Protection of mice from lethal endogenous Candida albicans infection by immunization with Candida membrane antigen

The protective effects of immunization with Candida membrane antigen (CMA) on a systemic infection originating from intestinally colonized Candida albicans were examined. The colonization of orally inoculated C. albicans in the intestinal tract was established in BALB/c mice that had been concomitantly treated with oral doses of antibacterial drugs. In these animals, a systemic dissemination of C. albicans with fatal outcome was induced by a repeated dosing of prednisolone. In this endogenous infection model, the effects of immunization by CMA on the infection were examined. CMA-immunized mice showed a longer lifespan than unimmunized mice. The protective effect of CMA immunization in immunosuppressed mice was also measured by a decrease in body weight loss after treatment with prednisolone and in the number of viable Candida cells in the target organs, the kidneys and livers. However, the CFU of C. albicans in the intestinal tract was not significantly lowered. These results suggest that CMA immunization inhibited the dissemination of systemic Candida infection from the intestinal tract induced by treatment with prednisolone.     

Antifungal activity of synthetic peptide derived from halocidin, antimicrobial peptide from the tunicate, Halocynthia aurantium

Halocidin is an antimicrobial peptide isolated from the hemocytes of the tunicate. Among the several known synthetic halocidin analogues, di-K19Hc has been previously confirmed to have the most profound antibacterial activity against antibiotic-resistant bacteria. This peptide has been considered to be an effective candidate for the development of a new type of antibiotic. In this study, we have assessed the antifungal activity of di-K19Hc, against a panel of fungi including several strains of Aspergillus and Candida. As a result, we determined that the MICs of di-K19Hc against six Candida albicans and two Aspergillus species were below 4 and 16 microg/ml, respectively, thereby indicating that di-K19Hc may be appropriate for the treatment of several fungal diseases. We also conducted an investigation into di-K19Hc's mode of action against Candida albicans. Our colony count assay showed that di-K19Hc killed C. albicans within 30s. Di-K19Hc bound to the surface of C. albicans via a specific interaction with beta-1,3-glucan, which is one of fungal cell wall components. Di-K19Hc also induced the formation of ion channels within the membrane of C. albicans, and eventually observed cell death, which was confirmed via measurements of the K+ released from C. albicans cells which had been treated with di-K19Hc, as well as by monitoring of the uptake of propidium iodide into the C. albicans cells. This membrane-attacking quality of di-K19Hc was also visualized via confocal laser and scanning electron microscopy.     

Thionin Thi2.1 from Arabidopsis thaliana expressed in endothelial cells shows antibacterial, antifungal and cytotoxic activity

Thionins are plant antimicrobial peptides with antibacterial and antifungal activities. Thionin Thi2.1 cDNA from Arabidopsis thaliana was expressed in BVE-E6E7 bovine endothelial cell line and its activity was evaluated against Escherichia coli, Staphylococcus aureus, Candida albicans and different mammal cell lines. Total protein (2.5 mug) from conditioned medium (CM) of clone EC-Thi2.1 inhibited the growth of E. coli, S. aureus (>90%) and C. albicans strains (>80%) in relation to the CM from control cells. Also, CM of EC-Thi2.1 inhibited the viability of several transformed and normal mammal cell lines (38-95%). These results suggest that thionin Thi2.1 is an antimicrobial peptide that could be use in the treatment of mammalian infectious diseases.     

Antibacterial action of ether oils of some plants

Inhibitory effect of clove oil on Escherichia coli, Staphylococcus aureus, Salmonella typhimurium, Shigella dysenteriae and Candida albicans was detected. Mint ether oil had the high antibacterial action on S. aureus, however against other microorganisms mint oil had a reliably low effect then clove oil. Fennel oil had high antibacterial effect on C. albicans, and bactericidal action on S. typhimurium and S. dysenteriae.     

Synthesis and potent antimicrobial activity of some novel 2-phenyl or methyl-4H-1-benzopyran-4-ones carrying amidinobenzimidazoles

Series of flavones and methyl-4H-1-benzopyran-4-ones carrying mono or diamidinobenzimidazoles at different positions were synthesized and evaluated for antibacterial and antifungal activities against E. coli, S. aureus, MRSA (methicillin-resistant S. aureus), MRSE (methicillin-resistant S. epidermidis), S. faecalis and C. albicans, C. krusei. The results showed that while all diamidines are inactive, the compounds having monoamidinobenzimidazoles at the C-6 position of the 2-phenyl-4H-1-benzopyran-4-one have potent antibacterial activities, particularly, against Gram-positive bacteria. Compounds 23 and 22 exhibited the best inhibitory activity with MIC values of 1.56 microg/ml against S. aureus, MRSA, MRSE and 3.12 microg/ml against C. albicans, respectively.