常见病原真菌鉴定基因芯片方法的建立

摘要

目的 建立临床常见的病原真菌的基因芯片检测体系.方法 选取8种临床常见真菌,包括白色假丝酵母菌、光滑假丝酵母菌、热带假丝酵母菌、近平滑假丝酵母菌、土曲霉、黄曲霉、米根霉和烟曲霉.根据真菌ITS区设计引物和探针,进行扩增和芯片制备.通过将待检真菌的PCR产物变性后与点布探针的芯片杂交,观察并分析荧光信号强度,进行对真菌的快速检测.并选取临床真菌阳性标本和细菌阳性标本共25份进行验证.结果 25份临床阳性标本的芯片检测结果显示,10份细菌阳性的标本,经真菌基因芯片检测,全部为阴性,无荧光信号.其余15份真菌标本中,12份临床真菌阳性标本均鉴定出芯片中的某一种真菌的结果.另外采用克柔假丝酵母菌人为制备的3份待检样本,经检测,芯片中8种真菌位点无荧光信号,为阴性,仅有真菌通用探针得到荧光信号,表明该标本中有真菌存在,但无法确认是哪一种.结论 本研究建立的基因芯片可对常见病原真菌进行快速准确的鉴定,为基因芯片应用于临床奠定了基础.%Objective To develop a gene microarray system for detection of clinical common pathogenic fungi.Methods There were 8 clinical common fungi chosen as the subjects including Candida albicans,Candida glabrata,Candida tropicalis,Candida parapsilokis,Candida pseudotropicalis,Aspergillus terreus,Aspergillus flavus,Aspergillus oryzae,Aspergillus fumigatus.Universal primers,probes and specific probes for the PCR amplification and microarray preparation were designed in ITS region of the fungi genomic DNA.The PCR products amplified from those fungi's genome DNA were denatured and hybridized with the probes in gene microarray.The rapid detection of fungi was based on the investigation on the fluorescent signal intensity in the chip.The detection results of gene microarray system were verified by true positive and negative clinical samples.Results There were totally 25 positive samples identified by clinical routine microbiological methods.The 10 samples identified as bacteria positive were determined as negative without fluorescent signal by the fungi gene microarray,while the 12 samples identified as fungi positive were determined as positive with certain fungus by the fungi gene microarray.And 3 artificial Candida krusei samples were detected as fungi positive,while they were failure to be identified as certain fungus.There was no fluorescent signal in positions of the 8 fungi specific probes,but there was fluorescent signal in the position of fungi universal probe.It indicated that there were fungi in the samples but it couldn't identify the species of the fungi,because the Candida krusei wasn't included in the detection fungi list of the fungi gene microarray.Conclusions The fungi gene microarray established by the study could detect the common fungi in clinic rapidly and accurately.This study lays technology foundation for clinical application of gene chip.