耐氟康唑的白假丝酵母菌主动外排机制初探

目的:了解对氟康唑耐药的白假丝酵母菌主动外排系统及主动外排基因CDR1的表达水平。方法:检测氟康唑敏感性和耐药性白假丝酵母菌对罗丹明6G主动外排情况,筛选出主动外排系统功能增强的菌株;采用Northern blot技术检测主动外排系统功能增强的菌株的CDR1基因的表达。结果:在由葡萄糖提供能量的体系中,5株耐药菌株外排罗丹明6G较敏感菌株明显增加,Northern blot发现其中4株CDR1基因表达水平升高。结论:耐氟康唑白假丝酵母菌主动外排基因CDR1表达升高。     

穿心莲内酯对白假丝酵母菌菌丝的影响

目的探讨中药有效成分穿心莲内酯（Andrographolide,AG）对白假丝酵母菌菌丝的影响。方法利用稀释涂布法观察AG对固体培养基上白假丝酵母菌菌落形态的影响;倒置显微镜观察AG对白假丝酵母菌芽管及菌丝形态的影响;采用xTT还原法评价AG对白假丝酵母菌菌丝活性的影响;采用实时荧光定量PCR（qRT—PCR）检测白假丝酵母菌菌丝形成相关基因SUN41、CSHl以及CaPDE2表达量变化。结果AG能影响白假丝酵母菌菌落的形态;倒置显微镜观察表明AG能够抑制白假丝酵母菌菌丝及芽管的形成;qRT-PCR检测显示AG能使SUN41和CSHl基因表达下调和使CaPDE2上调。结论穿心莲内酯可能通过影响SUN41、CSHl与CaPDE2基因的表达而抑制白假丝酵母菌菌丝的形成。     

氟康唑体外诱导白假丝酵母菌耐药基因表达的研究

目的 对白假丝酵母菌耐药机制进行研究.方法 将临床分离对氟康唑敏感的白假丝酵母菌种,经体外诱导产生耐药.半定量PCR检测敏感株、耐药株、回复敏感株多药耐药基因CDR1、CDR2、MDR1和转录调控因子TAC1编码基因表达水平的变化,并对TAC1编码基因进行测序.结果 与敏感株和回复敏感株比较,耐药株CDR1、CDR2相对表达量增高,发现1株TAC1 N977D氨基酸置换.结论 氟康唑体外诱导白假丝酵母菌产生耐药的机制与CDR1、CDR2表达相关.TAC1基因突变在诱导耐药中的机制有待进一步研究.     

应用流式细胞术对白假丝酵母菌耐药机制的研究

目的 探讨流式细胞术研究白假丝酵母菌耐药机制的可行性.方法 临床分离对氟康唑敏感的白假丝酵母菌种,经体外诱导产生耐药.应用荧光染料PI(碘化丙啶)和罗丹明123染色,通过流式细胞术检测敏感株、耐药株、回复敏感株的细胞周期和药物外排活性.结果 与敏感株和回复敏感株比较,耐药株增殖活性明显下降,但是药物外排活性显著增强.结论 应用氟康唑能够体外诱导白假丝酵母菌产生耐药.流式细胞术应用于白假丝酵母菌增殖活性和药物外排活性研究是可行的.     

转录因子RPN4对白念珠菌药物敏感性的研究

目的利用基因缺失菌库研究转录因子敲除后对白念珠菌药物敏感性的影响,并利用药物敏感性差异菌株初步考察可能的耐药性调控机制。方法微量液基稀释法测定最低抑菌浓度(minimal inhibitory concentration,MIC);点板法(spot assay)和生长曲线法验证菌株对氟康唑的敏感性;实时定量PCR(RT-PCR)法检测药物敏感性差异菌株中多药耐药基因CDR1和MDR1的表达,并通过罗丹明6G外排实验测定外排能力。结果亲本菌SN250对氟康唑表现为耐药,多药耐药基因CDR1和MDR1高表达,MIC80大于16μg/m L,大部分转录因子缺失菌与亲本菌SN250表现出相同的耐药性,但转录因子RPN4缺失菌株对氟康唑的敏感性升高,MIC80降为0.5μg/m L;多药耐药基因CDR1和MDR1的表达均降低,20 min和40min时对罗丹明6G的外排能力降低。结论转录因子RPN4有可能通过促进多药耐药基因CDR1和MDR1表达和菌株外排能力而降低对药物的敏感性,但相关机制有待进一步深入研究。     

芒果苷协同氟康唑抗耐药白念珠菌作用研究

目的研究芒果苷与氟康唑合用对唑类耐药白念珠菌协同抗真菌的作用和机制。方法采用棋盘式微量稀释法测试芒果苷协同氟康唑对22株耐药白念珠菌的最小抑菌浓度MIC80;时间-杀菌曲线探究两药联用对4株耐药白念珠菌生长的抑制作用;药物生长抑制实验实验探究不同浓度芒果苷和不同浓度氟康唑协同抗耐药白念珠菌药效;通过实时定量RT-PCR检测两药联用时耐药基因CDR1、CDR2、MDR1表达水平。结果芒果苷联合氟康唑可产生协同抗唑类白念珠菌作用,协同指数(FICI)0.5;两药合用对白念珠菌生长可产生抑制作用;两药合用降低耐药基因CDR1表达水平。结论芒果苷与氟康唑合用可产生协同抗唑类耐药白念珠菌作用。     

活性氧簇在白假丝酵母菌诱导RAW264．7细胞自噬中的作用

目的探究活性氧簇（ROS）是否参与白假丝酵母菌诱导RAW264．7细胞的自噬活化并明确其来源。方法RAW264．7细胞培养至对数生长期并分别以5种ROS生成系统抑制剂处理,白假丝酵母菌刺激细胞后采用二氯荧光素双醋酸盐（DCFH-DA）显示ROS水平,免疫印迹法检测LC3Ⅱ蛋白的表达量,免疫荧光技术观察LC3的表达与定位。结果白假丝酵母菌刺激后RAW264．7细胞的ROS与LC3Ⅱ表达水平显著升高,同时LC3呈斑点状聚集并与白假丝酵母菌共定位;NADPH氧化酶（NOX）抑制剂氯化二亚苯基碘翁（DPI）处理后ROS与LC3Ⅱ表达量明显降低,并且LC3在细胞内弥散分布;其他药物处理后ROS水平无显著变化。结论在白假丝酵母菌作用下NOX来源的ROS介导了RAW264．7细胞的自噬活化。     

皮肤性病门诊生殖道酵母菌阳性结果分析

摘要：目的 探讨生殖道假丝酵母菌阳性率、药敏情况及耐药趋势,为临床合理选用抗真菌药物提供最新的依据。方法 按照《全国临床检验操作规程》,采用法国梅里埃生物公司API-20C酵母菌鉴定板、ATB-Funguns酵母菌药敏板对2012年1月至2014年12月培养生殖道酵母菌阳性的标本进行鉴定及药敏试验。结果 1 419例生殖道分泌物分离出114例假丝酵母菌,感染率为8.0%,其中白假丝酵母菌101例占88.60%,感染率最高,其他非白假丝酵母菌13例占11.40%;药敏结果表明,假丝酵母菌对5-氟胞嘧啶、两性霉素B具有较高敏感性（92.11%、100.00%）,对氟康唑、伊曲康唑、伏立康唑呈现不同程度的耐药;101例白假丝酵母菌对5-氟胞嘧啶、两性霉素B的敏感性分别为93.07%、100.00%,未出现对两性霉素B的耐药菌株。结论 皮肤性病门诊生殖道酵母菌分离株仍以白假丝酵母菌为主,白假丝酵母菌对氟康唑、伊曲康唑、伏立康唑的耐药率呈上升趋势;微生物实验室应加强对假丝酵母菌株的分离鉴定及耐药性监测,为临床医生准确合理地使用抗真菌药物提供病原学依据。     

转录因子Pho4参与白念珠菌药物敏感性的调控

目的通过对缺失相应转录因子基因的白念珠菌进行抗真菌药物敏感性的筛选,考察转录因子对白念珠菌耐药性的影响及调控机制。方法通过微量液基稀释法、点板实验(Spot Assay)检测实验菌株对抗真菌药物的敏感性。采用实时定量PCR(RT-PCR)的方法检测白念珠菌耐药性相关MDR1,CDR1以及ERG11的表达,并通过检测菌株对罗丹明6G的外排能力进一步检测菌株对抗真菌药物的外排能力。结果最低抑菌浓度(minimal inhibitory concentration,MIC)测定和Spot Assay实验结果表明,与亲本菌相比,PHO4基因缺失菌对氟康唑、咪康唑的敏感性显著升高。虽然耐药相关基因的表达增加,但对罗丹明6G的外排能力降低,抗氧化应激能力下降。结论转录因子Pho4的缺失可能通过降低白念珠菌的抗氧化应激能力,减弱对药物的外排作用而导致对唑类药物敏感,但其具体的调控机制有待进一步研究。     

白假丝酵母菌耐药与抗氰呼吸的相关性研究

目的探讨白假丝酵母菌的耐药情况及其与抗氰呼吸的相关性。方法用真菌药敏测定试剂盒测定从临床分离出来的37株白假丝酵母菌的耐药性,并从中选出5株耐药菌和5株敏感菌进行抗氰呼吸的研究。结果白假丝酵母菌对益康唑的耐药率最高,达54.1%,耐药白假丝酵母菌的抗氰呼吸速率均值为(17.56±6.75)nmol/(min.A620),敏感白假丝酵母菌的抗氰呼吸速率均值为(7.99±5.80)nmol/(min.A620),耐药白假丝酵母菌的抗氰呼吸速率明显升高,且耐药菌株抗氰呼吸速率占总呼吸的比例明显高于敏感菌株(P0.05),差异具有显著性。结论兰州市区白假丝酵母菌对益康唑耐药性较高,且白假丝酵母菌的耐药与抗氰呼吸途径相关。     

Plagiochin E, a botanic-derived phenolic compound, reverses fungal resistance to fluconazole relating to the efflux pump

Aim: In this study, we investigated the effect of plagiochin E (PLE), a botanic‐derived phenolic natural product, on reversal of fungal resistance to fluconazole (FLC) in vitro and the related mechanism. Methods and Results: A synergistic action of PLE and FLC was observed in the FLC‐resistant Candida albicans strains and was evaluated using the fractional inhibited concentration index. The effect of PLE on FLC intracellular uptake was investigated in FLC‐resistant C. albicans cells by liquid chromatography–tandem mass spectrometry, and the effect on efflux drug pump was assessed by measuring the efflux of Rhodamine 123 (Rh123). PLE significantly inhibited the efflux, but not the absorption, of Rh123 in FLC‐resistant strains in phosphate‐buffered saline with 5% glucose. Overexpression of the multidrug‐resistance gene CDR1 in FLC‐resistant C. albicans isolates was detected, and the introduction of PLE to the cells showed a significant reduction of the CDR1 expression in those FLC‐resistant isolates. Conclusions: These findings indicate that PLE could reverse the fungal resistant to FLC by inhibiting the efflux of FLC from C. albicans, and this effect may be related to the efflux pump. Significance and Impact of the Study: These results indicate that the combination of PLE and FLC may provide an approach for the clinical therapy of fungus infection induced by FLC‐resistant strains.     

Antifungal activity of Rubus chingii extract combined with fluconazole against fluconazole‐resistant Candida albicans

This study aimed to investigate the antifungal activity of Rubus chingii extract in combination with fluconazole (FLC) against FLC‐resistant Candida albicans 100 in vitro. A R. chingii extract and FLC‐resistant C. albicans fungus suspension were prepared. The minimum inhibitory concentration and fractional inhibitory concentration index of R. chingii extract combined with FLC against C. albicans were determined, after which growth curves for C. albicans treated with R. chingii extract, FLC alone and a combination of these preparations were constructed. Additionally, the mechanisms of drug combination against C. albicans were explored by flow cytometry, gas chromatographic mass spectrometry and drug efflux pump function detection. R. chingii extract combined with FLC showed significant synergy. Flow cytometry suggested that C. albicans cells mainly arrest in G1 and S phases when they have been treated with the drug combination. The drug combination resulted in a marked decrease in the ergosterol content of the cell membrane. Additionally, efflux of Rhodamine 6G decreased with increasing concentrations of R. chingii extract. R. chingii extract combined with FLC has antifungal activity against FLC‐resistant C. albicans.     

Ibuprofen reverts antifungal resistance on Candida albicans showing overexpression of CDR genes

Several mechanisms may be associated with Candida albicans resistance to azoles. Ibuprofen was described as being able to revert resistance related to efflux activity in Candida . The aim of this study was to uncover the molecular base of antifungal resistance in C. albicans clinical strains that could be reverted by ibuprofen. Sixty-two clinical isolates and five control strains of C. albicans were studied: the azole susceptibility phenotype was determined according to the Clinical Laboratory for Standards Institute, M27-A2 protocol and minimal inhibitory concentration values were recalculated with ibuprofen (100 μg mL⁻¹); synergistic studies between fluconazole and FK506, a Cdr1p inhibitor, were performed using an agar disk diffusion assay and were compared with ibuprofen results. Gene expression was quantified by real-time PCR, with and without ibuprofen, regarding CDR1 , CDR2 , MDR1 , encoding for efflux pumps, and ERG11 , encoding for azole target protein. A correlation between susceptibility phenotype and resistance gene expression profiles was determined. Ibuprofen and FK506 showed a clear synergistic effect when combined with fluconazole. Resistant isolates reverting to susceptible after incubation with ibuprofen showed CDR1 and CDR2 overexpression especially of the latter. Conversely, strains that did not revert displayed a remarkable increase in ERG11 expression along with CDR genes. Ibuprofen did not alter resistance gene expression significantly ( P >0.05), probably acting as a Cdrp blocker.     

Candida biofilms

In response to attachment to a surface, fungal cells produce biofilms, three-dimensional structures composed of cells surrounded by exopolymeric matrices. Surface attachment causes Candida albicans cells to enter a special physiological state in which they are highly resistant to antifungal drugs and express the drug efflux determinants CDR1, CDR2 and MDR1. C. albicans biofilms produced under different conditions differ in their cellular morphology and matrix content, which suggests that biofilms formed within a host, for example on indwelling medical devices, would also differ depending on the nature of the device and its location. The mechanisms by which surface attachment leads to biofilm formation are presently not understood.     

黄芩素与氟康唑协同抗白念珠菌生物被膜作用研究

目的：研究黄芩素与氟康唑合用对白念珠菌生物被膜形成的影响。方法采用激光共聚焦显微镜观察黄芩素与氟康唑合用对白念珠菌生物被膜生长形态的影响;采用 XTT 法考察黄芩素与氟康唑合用对白念珠菌生物被膜形成能力的影响;应用水-烃两相测定实验考察黄芩素与氟康唑合用对白念珠菌生物被膜细胞表面疏水性（ Cell surface hydrophobicity, CSH）的影响;应用实时定量 RT-PCR（Real Time RT-PCR）实验考察黄芩素与氟康唑合用对白念珠菌 CSH1、EFG1、HWP1、ALS1基因表达的影响。结果黄芩素与氟康唑合用能够协同抑制白念珠菌生物被膜的形成,经黄芩素与氟康唑处理的白念珠菌不能形成正常的生物被膜,其生长动力学及细胞表面疏水性下降,细胞疏水性相关基 CSH1、菌丝形成调控基因EFG1、黏附相关基因 HWP1基因的表达水平降低。结论黄芩素与氟康唑合用可协同抑制白念珠菌生物被膜的形成。     

汉防己甲素及其联合氟康唑对白念珠菌细胞周期影响的初步研究

目的 探讨汉防己甲素联合氟康唑对白念珠菌细胞周期的影响.方法 将白念珠菌CA-1菌悬液与汉防己甲素和（或）氟康唑共培养12h,应用流式细胞仪测定空白对照组、汉防己甲素组、氟康唑组及汉防己甲素联合氟康唑组DNA含量.比较细胞周期各期DNA含量变化并计算增殖抑制率PI％,分析汉防己甲素及其联合氟康唑对白念珠菌细胞周期的影响.结果 汉防己甲素、氟康唑组与对照组S期DNA含量相比,分别能增加17.25％ （P =0.018）与6.54％ （P ＞0.05）,其联合运用效果更明显,S期DNA含量可增加31.52％ （P =0.002）.这说明汉防己甲素能将白念珠菌细胞阻滞在S期.结论 汉防己甲素能抑制白念珠菌细胞DNA合成,阻断白念珠菌细胞周期进程,抑制细胞分裂,其与氟康唑联用时阻滞作用更显著.     

Design,synthesis and evaluations of acridone derivatives using Candida albicans—Search for MDR modulators led to the identification of an anti-candidiasis agent

In order to search for MDR modulators, rationally designed acridone derivatives were investigated for their effect on influx or efflux of Rhodamine6G (R6G) in CAI4 cells. Results of these investigations indicate that in presence of compound 12, inhibition of growth of CAI4 cells and also an increased influx/efflux of R6G in CAI4 cells have been observed. This seems to be occurring due to the cell wall rupturing of Candida albicans. Compound 12 may be a suitable candidate for candidiasis therapy.