白色念珠菌致病机制研究进展

白色念珠菌是定植于肠道的一种可以造成体表或深部感染的条件致病性优势共生真菌。当机体免疫功能正常时，白色念珠菌表面抗原及代谢产物可以对机体免疫系统起到塑造作用，与宿主形成互惠共生的局面；但当机体免疫功能低下时，白色念珠菌便会成为致病性真菌，通过形成菌丝体、分泌念珠菌溶素及分泌细胞外囊泡等多种机制引起感染，甚至侵入血流造成播散性念珠菌病。深入探究白色念珠菌的致病机制对于进一步认识真菌，探寻新的治疗方法具有重要意义。     

外阴阴道念珠菌病与股癣

一、外阴阴道念珠菌病1.病因及传播途径:外阴阴道念珠菌病是由念珠菌所致的一种真菌病,也属于性传播疾病的范畴。90%以上病例由白色念珠菌所致,其余为热带念珠菌、类星形念珠菌或光滑软拟酵母菌等所引起。念珠菌是腐物寄生菌,可寄生于人体的阴道、口腔、消化道内,一般情况下不致病,但在一定     

白色念珠菌病的发病机制

念珠菌属 (特别是白色念珠菌 )为口腔中的常见真菌 ,在一定条件下致病。白色念珠菌可引起多种类型的口粘膜病 ,其临床表现及发病因素各有其特征。现将各型白色念珠菌感染的发病因素及机制介绍如下。1　急性假膜型此型又称雪口病、鹅口疮 ,多见于婴儿 ,损害区粘膜充血 ,有散在色白如雪的柔软小斑点 ,不久即相互融合为白色或黄色丝绒状斑片。此型多见于婴儿是因为在新生儿体内 ,特别是出生后 6个月以内 ,血清抑制因子比较低下。血清抑制因子存在于正常血清中 ,能使白色念珠菌凝集后被吞噬细胞杀灭 ,如血清抑制因子下降 ,可促使白色念珠菌感染…     

肺白色念珠菌病误诊为活动性肺结核 1 例简

肺念珠菌病是由念珠菌引起的急性、亚急性或慢性肺部感染,通常也包括支气管念珠菌病,统称支气管肺念珠菌病.病原体主要是白色念珠菌,其次是克柔念珠菌和热带念珠菌.临床发病率低,临床症状缺乏特征性,易误诊.我院2012年7月收治1例以反复咳嗽、咳痰为主要临床表现的白色念珠菌肺炎,误诊时间近半年,现结合文献复习分析如下.     

肺白色念珠菌病误诊为活动性肺结核1例

<正>肺念珠菌病是由念珠菌引起的急性、亚急性或慢性肺部感染,通常也包括支气管念珠菌病,统称支气管肺念珠菌病。病原体主要是白色念珠菌,其次是克柔念珠菌和热带念珠菌。临床发病率低,临床症状缺乏特征性,易误诊。我院2012年7月收治1例以反复咳嗽、咳痰为主要临床表现的白色念珠菌肺炎,误诊时间近半年,现结合文献复习分析如下。病例资料女,47岁,造纸厂工人。因咳嗽、咳痰两月余于2010-07-27入我院结核科。两个月前无明显诱因下出现阵发性咳嗽,非刺激性,干咳为主,偶有少量白     

念珠菌感染的菌种及耐药性分析

目的分析念珠菌属感染的菌种及耐药性。方法对321株念珠菌采用显色培养法及ATBTM FUN-GUS3真菌药敏试验板进行菌种鉴定和药敏试验。结果检出白色念珠菌192株,非白色念珠菌120株（主要为热带念珠菌、光滑念珠菌和克柔念珠菌）;念珠菌主要来自痰液标本,其余依次为尿液、粪便、分泌物、血液及其他标本。白色念珠菌对各种抗真菌药物耐药率较低;非白色念珠菌对氟康唑、伊曲康唑表现出不同程度的耐药,其中热带念珠菌、光滑念珠菌对5-氟胞嘧啶、两性霉素B耐药率较低,克柔念珠菌对氟康唑耐药率达100％,对伊曲康唑、5氟胞嘧啶的耐药率亦高于50％。结论临床真菌感染仍以白色念珠菌为主,非白色念珠菌感染呈上升趋势;不同念珠菌对常用抗真菌药物耐药性存在差异,白色念珠菌对抗真菌药物的耐药性低于非白色念珠菌。     

院内念珠菌感染的药敏分析及临床分析

目的了解并对比白色念珠菌与非白色念珠菌的临床分布、药敏情况。方法分析411株念珠菌的来源、科室分布,对比白色念珠菌与非白色念珠菌的药敏结果、危险因素等。结果 411株念珠菌的标本以痰液最多;ICU分离率最高;呼吸系统疾病最多;年龄≥65岁及侵袭性操作、药物使用,分别为感染白色念珠菌与非白色念珠菌的独立危险因素;念珠菌对两性霉素B最敏感;白色念珠菌对氟康唑、氟胞嘧啶、伊曲康唑、伏立康唑敏感性高于非白色念珠菌,对氟康唑、伊曲康唑的耐药率低于非白色念珠菌。结论加强对念珠菌耐药性的监测有助于减少耐药菌株的产生。     

肺结核合并白色念珠菌感染64例临床分析

目的：探讨肺结核合并白色念珠菌感染的临床特点及治疗，方法：回顾并分析5年来我科收治的肺结核合并肺部白色念珠菌感染64例的资料。结果：肺结核合并肺部白色念珠菌感染的特点，结核病史长，年龄偏大；以浸润型和慢性纤维空洞型肺结核为主；肺部病变广泛，空洞多，病情较重，多有继发真菌感染的诱因可寻；确诊有赖于病原学检查。结论：肺结核合并肺部白色念珠菌感染有增多趋势，了解其临床特点可提高对两病并存的诊治水平。     

肺结核合并白色念珠菌感染64例临床分析

目的　探讨肺结核合并白色念珠菌感染的临床特点及治疗。方法 回顾并分析5年来我科收治的肺结核合并肺部白色念珠菌感染64例的资料。结果 肺结核合并肺部白色念珠菌感染的特点:结核病史长,年龄偏大;以浸润型和慢性纤维空洞型肺结核为主;肺部病变广泛,空洞多,病情较重;多有继发真菌感染的诱因可寻;确诊有赖于病原学检查。结论 肺结核合并肺部白色念珠菌感染有增多趋势,了解其临床特点可提高对两病并存的诊治水平。     

口腔念珠菌病的诊治

口腔念珠菌病是由真菌—念珠菌属感染所致的口腔粘膜疾病 ,其中白色念珠菌是最主要的病原菌。鹅口疮 (雪口病 )是最常见的口腔念珠菌病。近年来 ,由于抗生素和免疫抑制剂的广泛应用 ,使口腔粘膜念珠菌病的发病率增高 ,长期慢性口腔念珠菌感染尚能引起恶变的可能 ,应引起重视。2 5 %～ 5 0 %健康人的口腔、阴道、消化道可带有念珠菌 ,但不发病 ,与机体处于共生状态 ,属非致病性念珠菌 ,在某种条件下 ,可转变为致病性的。其致病性取决于 :1病原菌的毒性和类型。白念菌为一卵圆形 G 芽生酵母样菌 ,在一定条件下能产生假菌丝 ,酵母型念珠菌无…     

Acquired immunity to systemic candidiasis in immunodeficient mice

Twenty-seven percent of beige-athymic (bg/bg nu/nu) mice died of systemic candidiasis 7-20 weeks after gastrointestinal tract colonization with Candida albicans. Conversely, beige-euthymic (bg/bg nu/+) mice colonized with C. albicans for a similar time period did not die or develop systemic candidiasis. C. albicans-colonized bg/bg nu/+ mice, but not bg/bg nu/nu mice, developed C. albicans-specific T cell-dependent antibody- and cell-mediated immune responses, indicating that T cell-dependent responses might explain the acquired resistance of bg/bg nu/+ mice to systemic candidiasis. Colonization with C. albicans enhanced the resistance of T cell-competent bg/bg nu/+ mice, but not bg/bg nu/nu mice, to systemic candidiasis. T cell-mediated immunity activated after mucosal colonization with C. albicans plays an important role in resistance to systemic candidiasis.     

The role of yeasts other than Candida albicans in oropharyngeal candidiasis

Candida albicans has been recognized as the predominant infecting organism in oropharyngeal candidiasis. Yeasts other than C. albicans are commonly recognized as colonizing the oral cavity but have not been thought to be a significant cause of disease. This review will describe the emergence of yeasts other than C. albicans as causative pathogens in oropharyngeal candidiasis both as co-infecting organisms with C. albicans and as sole pathogens themselves. Diagnosis and treatment of these emerging infections will also be discussed.     

Early diagnosis of candidiasis in non-neutropenic critically ill patients

OBJECTIVE: To determine a method for the early diagnosis of candidiasis in non-neutropenic critically ill patients in order to reduce mortality. METHODS: A prospective study in non-neutropenic critically patients in whom Candida spp. were detected, was made in an intensive care unit (ICU) during an 8-year period from 3389 patients admitted. A diagnostic and therapeutic protocol was designed. Invasive candidiasis was defined according to dissemination and multifocality. RESULTS: Candida spp. were found in 145 cases (4.3%): 120 (83%) were considered as invasive candidiasis and 25 as colonisation (17%). The hospital mortality was 46% (67/145). A post-mortem study was carried out in 54% (36/67) of hospital deaths. Candida albicans was the most frequently isolated species (87%), followed by Candida glabrata (18%). There were 24 candidemias and three cases of endophtalmitis. Digestive and respiratory samples and non-C. albicans yeasts were risk factors for invasive candidiasis. The mortality rate was related statistically to invasive candidiasis and inversely to the appropriate antifungal treatment. CONCLUSIONS: Invasive candidiasis is related to digestive and respiratory samples and to the presence of non-C. albicans species. A simpler definition of invasive candidiasis in non-neutropenic critically ill patients will permit more rapid and accurate specific antifungal therapy.     

Oesophageal candidiasis: clinical and mycological analysis

Oesophageal candidiasis is an epithelial infection which requires an immune deficiency. C. albicans is commonly the cause, although other species may also be responsible. Resistance to fluconazole, drug of choice for treatment, is an emerging problem. The objectives of the current paper were: to determine the frequency of oesophageal candidiasis in patients submitted to upper gastrointestinal endoscopy, analyze risk factors, identify Candida species and determine in vitro susceptibility to fluconazole. During 12 months, 34 patients with oesophageal candidiasis were detected. Out of 1.230 HIV negative and 91 HIV positive patients submitted to upper endoscopy, 11 (0.9%) and 23 (25.3%), respectively, had candidiasis. Risk factors for HIV negative patients were systemic antibiotic therapy in 2, deficient dental cleaning in 2 aged patients, use of proton pump inhibitors in 3, inhaled steroids in 2, malignancy in 1 and oral steroids in 1. The histopathologic diagnosis was confirmed in 48.6% of cases. Cultures were positive in 91.2% C. albicans was prevalent (93.5%), and was associated to other species in 5 cases (16.1%), (3 C. glabrata, 1 C. tropicalis and 1 C. parapsilosis). One case cultured only C. glabrata and 1, only C tropicalis. Out of 31 cultures, 25 were susceptible to fluconazole, 4 dose dependent (1 C. albicans, 3 C. glabrata), and 2 resistant (1 C. albicans, 1 C. glabrata). Frequency of oesophageal candidiasis was low, except for HIV positive patients. The most common etiologic agent was C. albicans, though other Candida species were also found. C. albicans and C. glabrata showed dose dependency and resistance to fluconazole.     

Effect of antibiotics and anti-cancer drugs on gastrointestinal infections and dissemination by C. albicans in mice inoculated orally with C. albicans

The authors studied the effect of antibiotics, hydrocortisone and anti-cancer drugs on gastrointestinal infections and dissemination by C. albicans in mice inoculated orally with C. albicans. The mice were given orally, vancomycin, amikacin and polymyxin B, and they also were injected with ampicillin and gentamicin. Hydrocortisone, cyclophosphamide (CPA) which causes leukopenia and neutropenia, and methotrexate (MTX) which injures the mucous membrane of the gastrointestinal tract were injected to the mice. In the mice treated with antibiotics and anti-cancer drugs, and inoculated orally with C. albicans, the colony forming units of the feces conspicuously increased. Gastrointestinal candidiasis was frequently observed, particularly at the cardia and the cardio-antrum line of the stomach of these mice. In addition to these sites, gastrointestinal candidiasis was observed at the antrum and the small intestine of the mice injected with MTX. C. albicans was frequently recovered from the livers and lungs of the mice treated with antibiotics and MTX + CPA which cause leukopenia, neutropenia and the damage of mucous membrane of the gastrointestinal tract. It is suggested that the threshold gut population of C. albicans is a determinant for gastrointestinal candidiasis, and that leukopenia, neutropenia and the damage of mucous membrane of the gastrointestinal tract are important factors for dissemination by C. albicans from the primary gastrointestinal lesions.     

Molecular typing of candida albicans isolated from oral lesions of HIV-infected individuals.

OBJECTIVE: To evaluate the epidemiology of Candida albicans infection in HIV-infected patients with oral lesions using molecular techniques. METHODS: Thirty-nine isolates from HIV-positive patients with oral candidiasis were examined using two DNA probes (a Histoplasma capsulatum ribosomal DNA probe that cross-hybridizes with C. albicans and a C. albicans strain-specific probe derived from repetitive sequence DNA). C. albicans obtained from the oral cavity of patients receiving cytotoxic chemotherapy was used as controls. RESULTS: Using the H. capsulatum ribosomal DNA probe, isolates were shown to members of many distinct classes of C. albicans. Forty-nine per cent (19 out of 39) of isolates were members of the same class; however, 46% (6 out of 13) of control C. albicans isolates were also members of this class. Further analysis of the class-restricted isolates from the HIV-infected patients using the C. albicans strain-specific probe showed that these could be further separated into distinct strains. CONCLUSIONS: These data indicate that strains of C. albicans that cause oral candidiasis in HIV-positive individuals are not clonally restricted and are similar to those colonizing the oral cavity of other severely immunocompromised hosts. Most patients appear to be infected with unique strains of C. albicans.     

Drosophila melanogaster as a facile model for large-scale studies of virulence mechanisms and antifungal drug efficacy in Candida species

Candida species are the predominant fungal pathogens in humans and an important cause of mortality in immunocompromised patients. We developed a model of candidiasis in Toll (Tl)-deficient Drosophila melanogaster. Similar to the situation in humans, C. parapsilosis was less virulent than C. albicans when injected into Tl mutant flies. In agreement with findings in the mouse model of invasive candidiasis, cph1/cph1 and efg1/efg1 C. albicans mutants had attenuated virulence, and the efg1/efg1 cph1/cph1 double mutant was almost avirulent in Tl mutant flies. Furthermore, the conditional tet-NRG1 C. albicans strain displayed significantly attenuated virulence in flies fed food without doxycycline; virulence was restored to wild-type levels when the strain was injected into Tl mutant flies fed doxycycline-containing food. Fluconazole (FLC) mixed into food significantly protected Tl mutant flies injected with FLC-susceptible C. albicans strains, but FLC had no activity in flies injected with FLC-resistant C. krusei strains. The D. melanogaster model is a promising minihost model for large-scale studies of virulence mechanisms and antifungal drug activity in candidiasis.     

The Evolution of Candida Species and Fluconazole Susceptibility among Oral and Vaginal Isolates Recovered from Human Immunodeficiency Virus (HIV)-Seropositive and At-Risk HIV-Seronegative Women

Antifungal agents can effectively treat mucosal candidiasis; however, their use can lead to colonization with less susceptible species and to resistance among normally susceptible strains. Oral and vaginal Candida isolates obtained at 3 points over 2 years from human immunodeficiency virus (HIV)-seropositive and at-risk HIV-seronegative women were identified by species and were evaluated for in vitro fluconazole susceptibility. Prevalence of non-C. albicans strains increased over time, and these strains were more likely among women reporting current antifungal use. Among C. albicans isolates, resistance was rare, with no evidence for progressive reduction in susceptibility over time. Among non-C. albicans isolates, reduced susceptibility occurred frequently and increased with time. HIV-seropositive women were more likely to have non-C. albicans isolates with reduced susceptibility as were women reporting current antifungal use. This evolution and selection of mucosa-colonizing Candida species with reduced susceptibility could play a critical early role in the development of antifungal resistance among C. albicans isolates responsible for refractory candidiasis.     

The evolution of Candida species and fluconazole susceptibility among oral and vaginal isolates recovered from human immunodeficiency virus (HIV)-seropositive and at-risk HIV-seronegative women

Antifungal agents can effectively treat mucosal candidiasis; however, their use can lead to colonization with less susceptible species and to resistance among normally susceptible strains. Oral and vaginal Candida isolates obtained at 3 points over 2 years from human immunodeficiency virus (HIV)-seropositive and at-risk HIV-seronegative women were identified by species and were evaluated for in vitro fluconazole susceptibility. Prevalence of non-C. albicans strains increased over time, and these strains were more likely among women reporting current antifungal use. Among C. albicans isolates, resistance was rare, with no evidence for progressive reduction in susceptibility over time. Among non-C. albicans isolates, reduced susceptibility occurred frequently and increased with time. HIV-seropositive women were more likely to have non-C. albicans isolates with reduced susceptibility as were women reporting current antifungal use. This evolution and section of mucosa-colonizing Candida species with reduced susceptibility could play a critical early role in the development of antifungal resistance among C. albicans isolates responsible for refractory candidiasis.