一种艰难梭菌毒素基因检测方法的临床应用评价

Evaluation of a real-time PCR assay for the qualitative detection of Ciostridium difficile toxin gene and its clinical application

目的 通过与BD MAX试剂盒检测临床粪便标本中艰难梭菌毒素基因的比对,评价本实验室前期研发的艰难梭菌毒素基因检测方法.方法 本研究为临床应用研究.2014年7月1日至9月30日采集浙江中医药大学附属杭州市第一医院的腹泻患者粪便标本147份,分别采用BD MAX和本实验室前期研发的艰难梭菌毒素基因检测方法进行检测.BD MAX试剂盒采用自动化核酸提取和PCR检测;实验室前期研发方法通过提取粪便DNA后进行荧光定量PCR检测,最后采用SPSS10.0软件进行分析.结果 147份标本中,两方法均检出艰难梭菌毒素B基因阳性33份,阴性114份,其中有4份标本的结果不一致.以BD MAX试剂盒的结果为标准,得出本实验室前期研发的艰难梭菌毒素基因检测方法的敏感度为93.94%（31/33）,特异度为98.25%（112/114）,阳性预测值为93.94 %（31/33）和阴性预测值为98.25 %（112/114）.且上述两种方法检测结果的一致性较好（Kappa值为0.922,P〈0.01）.结论 本实验室前期研发的艰难梭菌毒素基因检测方法与BD MAX试剂盒性能相似,敏感度高、特异度强,同时该方法成本低并可直接对腹泻标本进行测定,无需配套提取仪器,更适合我国临床开展常规艰难梭菌毒素基因检测.

Objective In comparison of the performances for the detection of Clostridium difficile toxin B genes from stool between BD MAX Cdiff assay and a laboratory-developed （LD） assay.The LD assay was evaluated in clinical application.Methods This study was a clinical application research.A total of 147 stool specimens from patients with diarrhea in Hangzhou First Hospital affiliated with Zhejiang Chinese Medical University were detected by the two assays from 1 July to 30 September 2014.DNA extraction and amplification of the tcdB gene were performed automatically on the BD MAX platform.Meanwhile, the tcdA and tcdB gene were detected by the LD real-time PCR assay after DNA extraction.Then, the results were analyzed by use of SPSS 10.0.Results A total of 147 stool samples were collected.There were 33 C.difficile positive cases and 114 negative cases detected by both of two assays.However, there were four stool samples had incongruent results.In comparison with BD MAX, the LD assay had a sensitivity of 93.94% （31/33）, a specificity of 98.25% （112/114）, a positive predictive value of 93.94% （31/33）, and negative predictive value 98.25% （112/114）.Furthermore, the results of the LD assay were statistically coherent with that of the BD assay （Kappa=0.922, P〈0.01）.Conclusions The LD assay was highly sensitive and accurate as BD MAX Cdiff assay in the detection of toxigenic Clostridium difficile.Furthermore, this LD assay could be also applied to detection of clinical stool samples directly with low cost.The assay will be more promising in diagnosis of toxigenic C.difficile in clinical application in China due to no additional instrument needed.