摘要
目的：由于抗生素、皮质类固醇激素、免疫抑制剂的广泛使用，以及HIV感染者的增多，侵袭性真菌感染尤其是白念珠菌感染呈明显上升趋势。目前临床对该病的诊断主要依靠血培养和组织病理检查，但阳性率低且费时长。PCR法是近年来较为受关注的诊断方法，它使标本中微量的DNA通过大量扩增而能被检测到。为了解PCR法对侵袭性念珠菌病的诊断价值，我们以白念珠菌标准菌株、侵袭性念珠菌感染小鼠血清为模板DNA，用内转录间隔区通用引物进行PCR扩增，测定PCR反应的敏感性和特异性。同时还监测了氟康唑对侵袭性念珠菌病的治疗作用。
实验方法：用改良煮沸法提取白念珠菌DNA，对不同菌量的白念珠菌进行PCR检测；PCR法测定感染小鼠血清，并与血培养、肝培养结果比较；PCR法检测感染实验组及氟康唑治疗组小鼠血清，监测氟康唑对侵袭性念珠菌病的疗效。
结果：浓度分别为1×106、1×105、1×104、1×103、1×102、1×101CFU/ml的白念珠菌PCR测定均能得到阳性结果，而菌量1×100CFU/ml时，PCR反应阴性；对于小鼠侵袭性念珠菌病，PCR比血培
养有更高的阳性率；治疗组PCR结果显示氟康唑对侵袭性念珠菌病有治疗效果。
结论：PCR法是一种快速、灵敏、特异性高的检查方法，对侵袭性念珠菌病的检测比血培养更为灵敏；氟康唑对侵袭性念珠菌病治疗有效，PCR可用于氟康唑疗效监测。
OBJECTIVE: The incidence of invasive candidiasis has increased greatly in recent years due to the frequent use of corticosteroid, immunosuppressant and antibacterial drugs. This incidence is even greater among patients infected with the human immunodeficiency virus (HIV).Standard methods for the diagnosis of Candida infections include blood culture and histopathology ,but these methods have limited sensitivity and specificity. The PCR assay for detection of fungal infection has been cared much in recent years. By amplification,it makes specimens with little DNA to be detected quickly. In this study, to investigating the diagnostic usefulness of PCR assay,we detected C.albicans in serum specimens of systemically infected mice by PCR, as well as the effects of invasive candidiasis treated with Fluconazole.
METHODS: 1.DNA extracted by boiling , we tested several different CFU of C.albicans by PCR assay. 2. PCR with serum from invasive candidiasis mice for diagnosis of candidemia comparing with
blood or liver culture. 3.PCR is used for monitoring the effects of invasive candidiasis treated with Fluconazole.
RESULTS: 1.The PCR results are positive for 1×106,1×105,1×104,1×103,1×102,1×101 CFU/ml of C.albicans respectively ,and negative for 1×100 CFU/ml. 2. For the neutropenic mice with an invasive infection, a higher percentage of positive test results was obtained by PCR than was obtained by conventional blood culture. 3.Fluconazole has good effects for invasive candidiasis of mice.
CONCLUSION: PCR assay is a better method for diagnosis of invasive candidiasis because it is more quickly, more sensitively, more specifically than blood culture, Fluconazole has good efficacy for treating invasive candidiasis, and PCR assay may be used for monitoring the effects of fluconazole for invasive candidiasis.
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