白念珠菌对唑类药物耐药机制的研究进展

随着唑类药物的广泛应用,白念珠菌对唑类药物的耐药现象越来越引起人们的重视.目前认为,白念珠菌对唑类药物的耐药机制主要有:ERG11的点突变或过度表达,抗真菌药物外排增加,生物膜的形成等.近年来,有关锌簇转录因子家族与耐药关系的研究逐渐增多,UPC2、TAC1和MRR1等锌簇转录因子的点突变可引起白念珠菌中耐药基因的过度表达而造成菌株对唑类药物的敏感性降低.     

白念珠菌临床株氟康唑敏感性试验与ERG11基因突变检测

目的 了解白念珠菌临床株对氟康唑的敏感性,筛查临床菌株的ERG11突变,探讨其与耐药的关系.方法 收集鉴定白念珠菌临床株,采用微量稀释法和药敏纸片法体外测定试验菌株对氟康唑的敏感性.分段扩增ERG11基因的第295～777bp(483bp)、第723～1204bp(482bp)和第1179～1667bp(489bp)等3个片段,并测序.结果 共收集念珠菌80株,分离白念珠菌52株,52株白念珠菌均为敏感株.经测序的5株敏感白念珠菌ERG11基因共出现19处突变,其中14处为同义突变,其余5处错义突变(T495A、A530C、G640A、A945C、G1609A)分别可引起羊毛甾醇14α-去甲基酶的下列氨基酸改变:D116E、K128T、E165K、E266D、V488I.结论 白念珠菌临床株对氟康唑敏感性较高;E165K和V488I可能与耐药无关.     

携带G487T和T916C的白念珠菌ERG 11及外流泵基因表达与氟康唑耐药的关系

目的:检测携带相同突变的耐氟康唑白念珠菌多个耐药基因的表达。方法:选取耐氟康唑白念珠菌14株(均携带相同的ERG11突变G487T和T916C),氟康唑敏感白念珠菌14株,通过实时定量PCR反应检测两组多个耐药基因的表达。结果:14株携带相同突变的耐氟康唑白念珠菌主动外排基因CDR1和CDR2 mRNA表达较敏感组显著增加(P0.01);而ERG11、FLU1和MDR1基因mRNA水平较敏感株表达无明显差异(P0.05)。结论:携带G487T和T916C突变的白念珠菌的耐氟康唑机制可能与主动外排泵基因CDR1和CDR2的高表达密切相关。     

ERG11和ERG3基因突变与念珠菌对氟康唑耐药的关系

目的探讨热带念珠菌、白念珠菌的ERG3、ERG11基因突变与其对唑类抗真菌药物耐药的关系,以初步探讨热带念珠菌对唑类药物耐药的机制。方法收集本院2015年3月-2016年10月期间临床分离的念珠菌52株,经体外药敏试验得到耐氟康唑的热带念珠菌6株、白色念珠菌1株;提取基因组DNA,通过PCR分别扩增6株热带念珠菌与1株白色念珠菌ERG11、ERG3基因,将扩增后的产物分别进行双向测序;将测序结果与热带假丝酵母菌标准菌株、白色念珠菌标准株的序列通过BLAST比对分析,找出突变基因。结果 6株热带念珠菌ERG11基因序列共发现3个同义突变与2个错义突变,ERG3基因共发现4个同义突变,6个错义突变;1株白色念珠菌耐药株ERG11基因共发现2个同义突变与2个错义突变,ERG3基因共发现2个同义突变,未发现错义突变。结论耐药菌株ERG11或ERG3存在不同程度的突变,这些突变可能参与热带念珠菌、白念珠菌耐药性的形成。     

DNA芯片鉴定念珠菌种和氟康唑耐药基因ERG11突变

目的 建立DNA芯片技术鉴定念珠菌种和氟康唑耐药基因ERG11突变。方法 根据6种常见念珠菌内转录间隔（ITS2）区种特异性序列和白念珠菌ERG11基因中已证实可导致对氟康唑耐药的6种突变序列设计探针,制备DNA芯片,鉴定12条50 bp的念珠菌种特异性序列和ERG11突变序列及34株念珠菌（其中白念珠菌29株,热带念珠菌、光滑念珠菌、都柏林念珠菌、近平滑念珠菌和克柔念珠菌各1株）。结果 ①芯片正确鉴定12条人工合成序列;②正确鉴定34株试验菌株的菌种;③正确鉴定29株白念珠菌ERG11基因中可致耐药的已知突变。敏感性和特异性均为100%。结论 用DNA芯片进行念珠菌菌种鉴定和白念珠菌ERG11突变筛查,结果可靠。     

滚环扩增技术检测耐氟康唑白念珠菌TAC1点突变

目的 利用滚环扩增技术检测耐氟康唑白念珠菌的TAC1点突变,建立一种准确、快速、特异的检测核酸单点突变的方法,同时进一步了解TAC1点突变与耐药的关系。方法 收集33株耐氟康唑白念珠菌（8株来自美国,25株来自澳大利亚）,根据文献报道的与耐药有关的点突变和挂锁探针设计原则设计4个挂锁探针。提取DNA、PCR扩增获得TAC1的三个目的片段;然后用滚环扩增技术检测耐药株的点突变。将滚环扩增所得结果与测序结果进行比较。结果 33株耐氟康唑白念珠菌中,有5株TAC1出现与耐药相关的点突变,分别为T225A（1株）和A736V（4株）,其中4株菌来自美国。4株氟康唑敏感白念珠菌中TAC1未见与耐药相关的点突变。结论 滚环扩增技术能准确、快速检测核酸单点突变;TAC1点突变与耐药的关系有待进一步研究。     

浅部与深部感染来源白念珠菌氟康唑耐药株药物敏感性及耐药基因突变比较

【摘要】 目的 比较浅部、深部感染来源的氟康唑耐药白念珠菌体外对8种抗真菌药物的敏感性及耐药基因突变。方法 26株深部感染来源白念珠菌耐药株、33株浅部感染来源白念珠菌耐药株,参照CLSI酵母菌检测方案M27-A4测定上述菌株对氟康唑、伏立康唑、伊曲康唑、泊沙康唑、两性霉素B、氟胞嘧啶、特比萘芬、米卡芬净8种药物单独或联合的体外敏感性。提取所有耐药菌株DNA,通过PCR检测ERG3、ERG11、FUR1 3种耐药基因的突变情况。满足正态分布和方差齐性检验的定量资料两组间比较采用独立样本t检验,不满足者组间比较采用Mann-Whitney U检验,定性资料组间比较采用卡方检验。结果 氟康唑、伊曲康唑、伏立康唑、泊沙康唑、氟胞嘧啶的最小抑菌浓度（MIC）在浅部感染组和深部感染组间差异均有统计学意义（均P＜0.05）,而两性霉素B、米卡芬净的MIC两组间差异无统计学意义（均P > 0.05）。96.6%的菌株特比萘芬MIC值＞64 μg/ml,无法进行组间对比。15株白念珠菌（7株深部感染来源、8株浅部感染来源）特比萘芬 + 唑类（氟康唑、伏立康唑、伊曲康唑、泊沙康唑）联合药敏试验均显示为协同效应,部分抑菌浓度（FIC）指数0.033～0.187;氟胞嘧啶 + 唑类、氟胞嘧啶 + 两性霉素B、两性霉素B + 氟康唑组合均无明显协同作用,FIC指数0.56～1.125。浅部感染来源白念珠菌ERG3基因突变包括错义突变V351A（33株,100%）,深部感染来源白念珠菌包括错义突变V351A（13株,50%）、A353T（4株,15%）;浅部感染来源白念珠菌ERG11基因突变包括错义突变I437V（32株,97%）、Y132H（23株,70%）、T123I（16株,48%）、K128T（6株,18%）、D116E（5株,15%）、A114S（4株,12%）、E266D（2株,6%）、G448E（2株,6%）、G465S（2株,6%）,深部感染来源白念珠菌包括I437V（23株,88%）、E266D（13株,50%）、E260G（5株,19%）、V488I（4株,15%）;浅部感染来源白念珠菌 FUR1基因突变包括错义突变R101C（11株,33%）,深部感染来源白念珠菌未检出错义突变。结论 浅部与深部感染来源白念珠菌氟康唑耐药株对药物的敏感性及基因突变位点均有所差别。     

艾滋病患者白念珠菌ERG11基因突变的研究

目的 探讨艾滋病患者的白念珠菌唑类耐药株中唑类抗真菌药物(氟康唑、伊曲康唑、伏立康唑)的作用靶位基因ERG 11基因突变与耐药的关系.方法 用PCR对临床分离的93株白念珠菌的Erg11基因进行扩增、测序,DNAman软件将测序结果与基因库中的X13296进行比对,将突变碱基翻译为氨基酸,确定是否发生错义突变.结果 共检出40个碱基突变位点,包括27个同义突变位点和13个错义突变位点.耐一种药物的突变菌株中每株菌只发生一处错义突变或无错义突变,而耐二种或三种药物的菌株中每株菌还可以同时出现两处或三处错义突变.结论 ERG 11基因错义突变与白念珠菌耐药有关.     

白念珠菌菌丝相和酵母相ERG11基因部分序列差异性的探讨

目的 研究白念珠菌菌丝相和酵母相细胞ERG11基因碱基序列上的差异，探讨两相细胞之间的差异性。方法 分别抽提从同—HIV阳性患者体内分离到的7株对氟康唑敏感程度不同的白念珠菌菌丝相和酵母相的DNA，此系白念珠菌经染色体水平及DNA水平证实来源于同一亲本。根据ERG11编码序列设计一对引物，对ERG11的近3’端的310bp的碱基序列进行PCR扩增，引物序列为：上游引物5’-GGGAAAGTTTCTAAAGGGG-3’：下游引物5’-TATGrITAATCCAACTAAGTAA-3’。经PCR产物直接测序比较两相细胞ERG11基因碱基序列上的差异。结果 1株氟康唑剂量依赖性敏感和2株氟康唑耐药白念珠菌的菌丝相与酵母相细胞间均出现ERG11基因1547位点、1587位点和1617位点的不一致。结论 白念珠菌的菌丝相和酵母相ERG11基因的部分序列存在差异。     

临床分离白念珠菌ERG4基因高表达与唑类抗真菌药物耐药的关系

目的 探讨临床分离白念珠菌ERG4基因高表达与唑类抗真菌药物耐药的关系。 方法 M27-A2微量肉汤稀释法对34株临床分离白念珠菌菌株进行体外药物敏感性试验。抽提白念珠菌ERG4基因的总RNA,并逆转录合成cDNA,采用实时荧光定量PCR（FQ-RT-PCR）方法检测ERG4基因mRNA表达水平。结果 白念珠菌耐氟康唑菌株组ERG4基因表达量（4.20 ± 2.56）高于敏感组（1.72 ± 1.33）（t = 3.99,P < 0.05）;耐伊曲康唑组（3.60 ± 2.47）高于敏感组（1.66 ± 1.61）（t = 3.71,P < 0.05）;耐伏立康唑组（3.99 ± 2.72）高于敏感组（2.07 ± 1.58）（t = 2.91,P < 0.05）;对氟康唑、伊曲康唑、伏立康唑同时耐药菌株组（4.49 ± 2.73）显著高于敏感组（1.69 ± 1.82）（t = 3.81,P < 0.05）。 结论 临床分离白念珠菌耐药菌株ERG4基因高表达与氟康唑、伊曲康唑和伏立康唑耐药及交叉耐药有关,但白念珠菌ERG4基因高表达在耐药中的作用还有待于通过基因下调进一步研究证实。     

Dermatology in private practice in France in 2000

OBJECTIVES: Data regarding French dermatological practice are scarce. Our objective was to identify the skin disorders most commonly diagnosed by office-based dermatologists. We also documented the severity of these skin disorders, as reflected by the repercussions on patient's everyday life, and the way physicians managed patients. DESIGN: We carried out a one-day survey of visits to a randomly selected sample of 900 French office-based dermatologists. The randomization was stratified according to the five French different dialing area codes. RESULTS: Office-based dermatologists saw 6411 patients with 7839 skin disorders during the survey. The daily number of visits to French dermatologists was estimated at 47 000 and the annual number between 12 and 14 millions. Office-based dermatologists mostly managed warts, acne, nevus, dermatitis, malignancies and pre-malignancies, fungal infection and psoriasis. Repercussions on patients'everyday life were assessed by physicians as important or very important in 28 p. 100 of cases. Half of the patients received topical treatment, 20.5 p. 100 a systemic drug and 40 p. 100 a minor surgical procedure (including cryotherapy). CONCLUSION: Although dermatologists frequently see benign skin disorders such as warts or nevus, more severe diseases represent an important part of their activity.     

Pentoxifylline in reactions in leprosy

A study was conducted to assess the response of reactions in leprosy to pentoxifylline therapy. Ten cases were studied; 8 cases had type 2 reaction and 2 cases had type 1 reaction. Pentoxifylline was given orally 400 mg three times daily. In patients with type 2 reaction, good response was observed within one week. There was near complete regression of ENL lesions within one month. Cases with type 1 reaction did not respond to pentoxifylline.     

Absenteeism in leprosy patients in a rural area in Tamil Nadu

Of the 3382 leprosy patients taking treatment in Hemerijckx Rural Centre Area, 150 randomly selected patients, who were irregular for treatment, were matched with 150 patients who were regular for treatment, by age, sex and type of disease. The characteristics and the reasons for regularity/irregularity in treatment of these 300 patients were studied. There were more Lepromatous patients (20%) among regulars. A greater proportion of irregulars belonged to backward (54%) and scheduled castes (35%). The proportion of irregulars were more (32%) in the initial phase of the disease. There were more irregular patients among the illiterate group (61%). The knowledge of the irregular patients about early sign, causation, spread, curability and duration of treatment were found to be lacking. The clinic timing was unsuitable for 33% of irregular patients. 23% of irregulars experienced some intolerance to DDS. When 94% of regulars attended clinic in order that they may be 'cured', 63% of irregulars stayed away because of 'work'.     

Leukocyte migration in vivo and in vitro in patients with psoriasis

Leukocyte migration in vivo was studied with a skin chamber technique in 21 patients with active psoriasis vulgaris and 18 with cleared psoriasis vulgaris. Measuring over 24 h, no difference was found between healthy volunteers and most patients with active psoriasis, although a subgroup of patients with long-lasting relapses showed subnormal migration values. In patients with cleared psoriasis on the other hand the in vivo leukocyte migration values were increased. In addition, leukocyte migration in vitro under agarose was studied, but no difference was found between healthy controls and patients with psoriasis, active or cleared.