摘要
为了探讨快速诊断系统性白念珠菌感染的方法,我们应用聚合酶链式反应(PCR)技术体外扩增编码白念珠菌细胞色素P_(450)L_(1)A_(1)的基因片段,在8h内可检出1ml中含有20个菌体的标本。在烧伤系统性白念珠菌感染模型中,对30只兔的200份血标本,120份尿标本和临床8例严重烧伤患者的26份标本(包括血、尿、痰和创面分泌物)进行了检测,并与培养法对比,结果显示:①在烧伤感染动物血标本的PCR检出率显著高于培养法(P<0.01);动态组中,PCR对尿的检出率也高于培养法(P<0.05);临床标本的检测结果与之类似。②PCR诊断系统性白念珠菌病的敏感性、准确性及阴性预测值均高于培养法。我们认为用PCR诊断系统性白念珠菌感染,敏感、快速、特异,还可望用于临床监测、疗效评价及判定感染复发等方面。
For rapid diagnosis of systemic candidiasis, the polymerase chain reac- tion (PCR) was used to amplify a segment of Candida albican DNA coding for the cy- tochrome P)(450) L_1A_2 in vitro. The technique provided unambiguous evidence of the pres- ence of Candida albicans in as short as 8 hours with a detection threshold of 20 organ- isms. 200 blood and 120 urine specimens were collected from thirty rabbits with burn and candidiasis. Specimens of blood (n=6), urine (n=6), sputum (n=7) and wound exu- date (n=7)were also collected from eight serious burn patients. PCR technique was used in all the specimens, and the result was compared with conventional fungus culture. It was shown that:①The positive detection rate of Candida by PCR was significantly high- er than by culture for blood specimens (P<0. 01)and serial specimens of urine (P<0.05)in infected burn animals. The clinical specimens showed the same results;② In evaluating diagnostic value of PCR for systemic Candida albicans infection, it was found that sensitivity, accuracy and negative prediction rate were superior to the con- ventional culture method. These results suggest that PCR technic may provide a rapid sensitive and specific means for the diagnosis of systemic Candida albicans infection. In addition, it may be helpful in the evaluation of therapeutic response or recurrence of in- fection.
