白色念珠菌肠内定植导致局部调节因子表达增加

目的 观察白色念珠菌肠腔内定植后局部调节功子表达变化。方法 采用无特殊病原菌小鼠定植白色念珠菌,分别于定植后３ｄ,７ｄ,１４ｄ活杀,观察如下指标：盲肠内白色念珠菌总数;潘氏结（ＰＰ）中斑点杂交观测ＩＬ－４,ＩＬ－６表达变化;通过原位杂交反映固有层中（ＬＰ）ＩＬ－６表达变化;ＥＬＩＳＡ测定肠匀浆中ＩＬ－６水平。结果 白色念珠菌总数以定植３ｄ,７ｄ较高,１４ｄ则明显下降;ＰＰ中ＩＬ－４表达以定植１４ｄ     

白色念珠菌致病性研究

目的了解我院临床标本中白色念珠菌的致病性.方法对我院2002年1月～2003年12月150株临床标本分离的白色念珠菌进行蛋白酶测定,并从蛋白酶活力高、中、低的白色念珠菌中分别选2株作血管内皮细胞毒力、黏附性测定.结果150株白色念珠菌全部检出蛋白酶,其中蛋白酶活力高的113株占75.3%;中等24株占16%;低的13株占8.7%;细胞毒力试验表明蛋白酶活力越高,细胞毒性越强,蛋白酶活力与毒力呈正相关(r=0.9946、P＜0.01);细胞黏附试验表明蛋白酶活力越高,黏附能力越强,蛋白酶活力与黏附呈正相关(r=0.9944、P＜0.01).结论蛋白酶是白色念珠菌重要的毒力因子,活力可直接反映其毒力,蛋白酶活力与其黏附直接相关;临床标本中白色念珠菌具有相当的致病性,临床应重视.     

DNA relatedness,karyotyping and gene probing of Candida tropicalis,Candida albicans and its synonyms Candida stellatoidea and Candida Claussenii

Isolates of Candida albicans with varied phenotypes, including sucrose-negative variants (C. stellatoidea, serotypes A and B) and avirulent germ tube-negative forms (C. claussenii) showed significant (> 90%) DNA relatedness to classical C. albicans, but insignificant relatedness to C. tropicalis and sucrose-negative C. tropicalis. A transverse alternating-field gel electrophoresis procedure (TAFE) showed discrete karyotype patterns among the phenotypic variants of C. albicans including the sucrose-negative C. stellatoidea. The number of chromosome-sized DNA bands for C. tropicalis (7 bands) were within the range of bands observed for C. albicans (5 to 10 bands). The general DNA-migration pattern for C. albicans appeared distinct from that of C. tropicalis. An aspartyl proteinase (PrA) gene probe from C. albicans hybridized with chromosomal DNA from C. albicans, C. claussenii and C. stellatoidea but not with that from C. tropicalis.     

白假丝酵母菌基因分型方法的研究进展

正随着医疗技术的快速发展,各种医用材料和侵入性操作技术在临床广泛应用,广谱抗菌药物、糖皮质激素和免疫抑制剂在临床的大量使用,医院内真菌感染的比例越来越高,其中白假丝酵母菌在真菌感染中所占比例最高,是临床中常见的致病菌之一。白假丝酵母菌主要引起皮肤、黏膜的浅表部位感染,侵袭性呼吸系统感染和血流感染等,其中血流感染相对严重,如白假丝酵母菌血症。早在二十世纪八十年代,Pfaller等~([1])报道,侵袭性假丝酵母菌感染     

Fungal cell adhesion molecules in Candida albicans

Adherence of Candida albicans to host tissues is considered a crucial step in the pathogenesis of candidiasis. Using in vitro assays, it was demonstrated that the yeast — mycelium transition was an important phenomenon in the acquisition of adhesive properties. Proteins with MWs of 60, 68, 200 and > 200 kDa seemed to be involved in germ tube adherence to plastic surfaces. Likewise, recent investigations have revealed that C. albicans expresses on its surface receptors which interact with a wide variety of host proteins, particularly some extracellular matrix components like fibronectin, laminin and collagen. Plasmatic components, such as fibrinogen, iC3b and C3d, have also been proposed as mediators of adherence of C. albicans. Thus, by their reaction with laminin, fibrinogen and C3d, the mannoproteins of 68 and 60 kDa demonstrated multiple biological activities. Proteins of similar MWs were detected as C3d and iC3b receptors, the latter showing similarities with the neutrophil CR3. Based upon the antigenic, structural and functional homologies between the candidal receptors and mammalian integrins, it was postulated that these fungal cell adhesion molecules (F-CAM) are members of the integrin family. Interactions with host proteins and molecular mimicry of mammalian adhesion molecules may be a fertile area for further research.Corresponding author.     

嗜酸乳杆菌与白色假丝酵母菌交互作用

目的对嗜酸乳杆菌与白色假丝酵母菌间的交互作用及pH、乳酸、乙酸、H2O2等对白色假丝酵母菌生长影响进行评价,为细菌性阴道病治疗后易转为外阴阴道假丝酵母菌病的原因提供依据。方法不同浓度嗜酸乳杆菌、白色假丝酵母菌混合培养;白色假丝酵母菌经不同pH值培养基培养、1%乳酸、1%乙酸、3%H2O2作用,检测其浓度变化,形态学观察白色假丝酵母菌形态变化。结果嗜酸乳杆菌浓度依赖性抑制白色假丝酵母菌生长,白色假丝酵母菌可促进嗜酸乳杆菌生长;pH值为3.5~5.5时,嗜酸乳杆菌具有较强的抑菌能力,当pH值为4.0时,嗜酸乳杆菌抑菌能力最强;乳酸、乙酸均对白色假丝酵母菌生长有明显抑制作用且具有浓度和时间依赖性,H2O2对白色假丝酵母菌生长并无直接抑制作用。结论嗜酸乳杆菌主要通过其代谢产物乳酸而不是H2O2直接产生抑菌作用,细菌性阴道病治疗后转为外阴阴道假丝酵母菌病的发生,主要与乳杆菌因某些因素生长受抑,导致数量降低及其产酸能力下降有关。     

Determination of Candida albicans mannan antigen in serum

An enzyme-linked immunosorbent assay (ELISA) for detection of Candida albicans mannan antigen in sera pretreated with pronase was used for investigation of antigenemia in 3 groups of patients: Group A: No antigen was detected in patients (n = 270), which were under control by a mycological surveillance programme. They were clinically not suspicious of candidosis and had no remarkable mycological findings. Group B: Candida antigen was detected in 13 cases of 158 patients (= 8.2%), which suffered from unclear clinical symptoms. Therefore a mycological laboratory diagnosis was performed yielding no remarkable findings neglecting the positive antigen detection. Group C: Candida antigen was also detected in 9 cases of 64 patients (= 14.0%), which were suspicious of candidosis and/or had remarkable mycological laboratory findings. The difference between the frequency of antigenemia in group B and C was not significant. According to our preliminary experiences the detection of Candida mannan antigen may support the early diagnosis of invasive candidosis. Yet antigen findings should not be separately interpreted but included in all available clinical and mycological results.     

念珠菌血症中白假丝酵母的分子流行病学研究

目的探讨念珠菌血症中白假丝酵母的基因分型,了解其流行病学特征。方法收集患者血培养阳性,经科玛嘉显色培养基进行菌株的初步筛选;用扩增真菌的转录间隔间区(ITS区)和核糖体大亚基(26rRNA、D1/D2区)、基因测序对初筛的菌株进行标准的分子生物学鉴定;利用白假丝酵母的七对管家基因多位点序列分型,利用软件分析其亲缘关系。结果各管家基因的等位基因的同一位点可出现多次碱基变异;在管家基因中ACC1基因的碱基变异位点最少,仅4个,而SYA1基因的碱基变异位点最多;16株白假丝酵母可分为10个群,其中一个群由5个菌株构成,2个群都是由2个菌株构成,其他的群都是由一个菌株单独构成。结论白假丝酵母的二倍体序列型都为新发的基因型,未发现流行的克隆株。     

肠道白色念珠菌易位体内机制的研究

目的观察白色念珠菌发生易位的机制. 方法无特殊病原菌(SPF)小鼠分为正常对照组、正常给菌组,给菌后烧伤组、烧伤对照组,观察白色念珠菌黏附计数、易位,肠黏液中特异抗白色念珠菌sIgA;体外观察白色念珠菌黏附、侵入肠上皮细胞内情况. 结果在肠内特异sIgA较低时,白色念珠菌黏附数较多,发生易位;体外实验环境中白色念珠菌浓度越高,黏附、侵入的阳性细胞数量越多. 结论白色念珠菌黏附后侵入肠上皮细胞内,是发生易位的重要途径之一,特异抗白色念珠菌sIgA对此有预防作用.     

白色念珠菌的毒力因子及耐药机制的研究进展

白色念珠菌为机会感染性病原菌,是健康人群正常菌群的一部分,当机体免疫功能破坏、菌群失调或经污染的器械手术,会造成致命性感染.此文对白色念珠菌的毒力因子和耐药机制进行综述.     

白色念珠菌在呼吸道中致病性的研究

目的了解呼吸道标本中白色念珠菌的致病性并评价其分离的临床意义.方法对我院2000年1月～2001年8月100株呼吸道分离的白色念珠菌进行蛋白酶测定,并从蛋白酶活力高、中、低中分别选2株作血管内皮细胞细胞毒力、粘附性测定.结果 100株白色念珠菌全部检出蛋白酶,其中蛋白酶活力高的71株占71%;中等18株占18%;低的11株占11%;细胞毒力试验表明蛋白酶活力越高、细胞毒性越强、蛋白酶活力与毒力直接正相关(r=0.9946,P<0.01);细胞粘附试验表明蛋白酶活力越高、粘附能力越强、蛋白酶活力与粘附直接正相关(r=0.9944,P<0.01).结论蛋白酶是白色念珠菌重要的毒力因子,蛋白酶活力可直接反映其毒力,蛋白酶活力与其粘附直接相关,呼吸道标本中白色念珠菌具有一定的致病性,临床应密切关注.     

Strain differentiation of Candida albicans by morphotyping

Strains of Candida albicans can be differentiated by the morphological features of streak colonies developed on malt agar. A morphotyping system is proposed, where numerical codes are assigned primarily on the basis of the nature and extent of marginal fringing and the surface topography of the streak colony. The system allows ready differentiation to be made of morphotypes, requires no specialized equipment or expertise and provides a simple and reproducible means for epidemiological studies of candida and candidosis.     

白色念珠菌对唑类抗真菌药物的耐药机制探讨

目的探讨白色念珠菌对唑类抗真菌药物的耐药机制。方法从复发性外阴阴道念珠菌病(RVVC)患者分离出白色念珠菌,采用NCCLS公布的《酵母菌液基稀释法抗真菌药物敏感试验参考方案》(M-27方案)进行体外药敏试验,分离出氟康唑(FLC)及伊曲康唑(ITC)的耐药株;随机选择4株耐FLC和ITC白色念珠菌耐药株,分别用A1-A2、B1-B2、C1-C2、D1-D2、E1-E2、F1-F2 6对引物进行PCR扩增,将其产物测序,并与NCBI网站提供的白色念珠菌参考株进行比对、分析。结果4株耐FLCI、TC白色念珠菌的CYP 51基因全序列比对、分析,发现有32个碱基发生了突变,但引起氨基酸的突变只有5个,分别是:第116位遗传密码GAT变成GAA,导致该位置的天冬氨酸(D)突变为谷氨酸(E)(D116E 1株);第117位遗传密码GCT变成GGT,导致该位置的丙氨酸(A)突变为甘氨酸(G)(A117G 1株);第266位遗传密码GAA变成GAC,引起该位置的谷氨酸(E)突变为天冬氨酸(D)(E266D 2株);第488位的遗传密码GTT变成ATT,导致该位置的缬氨酸(V)突变为异亮氨酸(I)(V488I 1株);其中有1株菌分别在第266和488位同时发生了突变。结论本研究发现5个有意义的碱基突变,引起其编码的氨基酸发生了突变,其中A117G的突变目前尚未见相关报道,它在耐药机制中的作用尚需进一步探讨。