Objective: To evaluate the diagnostic efficacy of real?time polymerase chain reaction (q?PCR) for Clostridium difficile infection (CDI) in comparison with routine culture and enzyme?linked fluorescent spectroscopy?based aprroaches.
Methods: Stool samples were collected from suspected CDI cases in General Hospital of Guangzhou Military Command of PLA between May and December in 2016. All the samples were examined with 3 methods, namely enzyme?linked fluorescent spectroscopy for detecting Clostridium difficile toxin A/B (CDAB), detection of glutamate dehydrogenase (GDH), and q?PCR for amplification of Clostridium difficile?specific gene tpi and toxin gene (tcdA/tcdB), with the results of fecal culture as the reference for evaluating the diagnostic efficacy of the 3 methods.
Results: Of the total of 70 fecal samples, 13 (18.57%) were found to be positive for Clostridium difficile, including toxin?producing strains in 6 (8.57%) samples. The sensitivity, specificity, positive predictive value, negative predictive value and diagnostic coincidence rate of q?PCR for tpi were 92.31%, 91.23%, 70.59%, 98.11% and 91.43%, respectively, which were significantly higher than those of GDH test (84.62%, 84.21%, 55.00%, 96.00%, and 84.29%, respectively; Χ2=24.881, P<0.001). The sensitivity of q?PCR for tcdA/cdB was significantly higher than that of enzyme?linked fluorescent spectroscopy for CDAB in detecting CDI (66.67% vs 33.33%; Χ2=35.918, P<0.001).
Conclusion: Both CDAB detection and q?PCR have a high specificity in detecting CDI, but GDH detection has a good sensitivity, and all these 3 methods have a high negative predictive value. Compared with other detection methods, amplification of tpi and tcdA/tcdB using q?PCR allows more rapid, sensitive and specific detection of CDI.
目的: 评价3种艰难梭菌感染（CDI）检测方法的诊断效能，为CDI寻找合适的诊断方案。
方法: 收集中国人民解放军广州总医院2016年5月~12月疑似CDI的腹泻患者粪便标本70例，采用3种方法进行检测：（1）培养法；（2）酶联荧光法检测艰难梭菌毒素A/B（CDAB）和谷氨酸脱氢酶（GDH）；（3）q-PCR扩增艰难梭菌特异性基因tpi和毒素基因（tcdA/tcdB）。以培养法的检测结果作为参考标准，计算3种方法的诊断指标。
结果: 收集粪便样本70例，分离艰难梭菌13例（18.57%），其中产毒株6例（8.57%）。q-PCR法鉴定tpi基因阳性17例，其敏感度、特异度、阳性预测值、阴性预测值、诊断符合率分别为92.31%、91.23%、70.59%、98.11%、91.43%，均高于GDH法（84.62%、84.21%、55.00%、96.00%、84.29%）（χ2=24.881，P < 0.001），且q-PCR扩增tcdA/ tcdB的敏感度（66.67%）优于CDAB（33.33%）（χ2=35.918，P < 0.001）。
结论: CDAB检测和q-PCR法特异性较高，GDH法具有较好的灵敏度，3者均有较高的阴性预测值。与其他检测方法相比，q-PCR法检测CDI具有时效性强，灵敏度高，特异性好等优势，适用于临床推广。