3种检测艰难梭菌方法的临床应用评估

本研究旨在对3种检测粪便样本中艰难梭菌的方法进行临床应用评估,为艰难梭菌的实验室检测提供参考。采用艰难梭菌毒素A/B(Clostridium difficile toxins A and B,CDAB)酶联免疫荧光检测法、环丝氨酸-头孢西丁-果糖琼脂(cycloserin-cefoxitin-fructose agar,CCFA)常规培养法和显色培养法(chromID~(TM))同步检测粪便样本中的艰难梭菌,并对培养所得菌株进行tcdB基因扩增以验证其产毒性。以艰难梭菌培养联合tcdB基因扩增为参考方法,分别计算上述3种方法的灵敏度、特异度、阳性预测值和阴性预测值等参数,分析其与参考方法的一致性。研究共收集临床粪便样本164份,参考方法检测结果为58份阳性,106份阴性。经统计分析,艰难梭菌毒素A/B法的灵敏度、特异度、阳性预测值和阴性预测值分别为51.7%、95.3%、85.7%和78.3%,CCFA常规培养法分别为72.4%、98.1%、95.5%和86.7%,而艰难梭菌显色培养法分别为94.8%、92.5%、87.3%和97.0%。3种方法中,艰难梭菌显色培养法与参考方法的一致性最高(Kappa=0.856)。采用该方法检测粪便样本中的艰难梭菌操作简便,成本经济,结果判断直观、准确,具有较好的临床应用价值。

Clinical evaluation of three methods in detection of Clost ridium difficile in stool

This study aims to evaluate the clinical performance of three methods in the detection of Clostridium difficile ( C . difficile) in stool samples . Clinical samples were subjected to enzyme-linked fluorescence assay for C . difficile toxins A and B (CDAB ) , conventional bacterial cultivation using cycloserine-cefoxitin-fructose agar (CCFA ) and cultivation by chromogenic C . difficile identification medium (chromIDTM ) ,respectively .A combination of bacterial culture and amplification of the tcdB gene was selected as the standard reference method for the evaluation .A total of 164 clinical stool samples were collected ,of which 58 had positive results by the reference method whilst the rest 106 were negative .The CDAB method showed a sensitivity ,specificity ,positive predictive value and negative predictive value of 51 .7% ,95 .3% ,85 .7% and 78 .3% ,respectively ,while the corresponding values of the CCFA method turned out to be 72 .4% , 98 .1% , 95 .5% and 86 .7% , respectively . The chromIDTM method gave corresponding values of 94 .8% , 92 .5% , 87 .3% and 97 .0% , respectively . Among the three methods , chromIDTM method had the best consistency with the reference method (Kappa= 0 .856) .It is concluded that chromIDTM is a simple and cost-effective method for the detection of C . difficile in stool samples , which can present easy-to-judge results and has a preferable value in clinical application .