Issarachaikull Ratima, Khantipong Mayuree, Sawatpanich Ajcharaporn, Suankratay Chusana
Southeast Asian J Trop Med Public Health. 2015 Nov;46(6):1037-48.
Abstract. Clostridium difficile infection (CDI) is one of the most common nosocomial infections in Thailand and worldwide. The clinical spectrum ranges from annoy- ing diarrhea to severe life-threatening disease. Enzyme-linked immunofluorescent assay for cytotoxins A/B (cytotoxins A/B ELFA), which has been widely used in our institute, generally is considered as having low sensitivity for diagnosis of CDI. The study was a prospective evaluation of a novel two-step diagnostic algorithm, in which the first step involved concurrent cytotoxins A/B ELFA and enzyme immunoassay for glutamate dehydrogenase (GDH EIA) for CDI, followed by PCR assay of tcdA and tcdB in samples with discordant results. Of the 91 adult patients (37 males and 54 females, mean age of 60.0 ± 19.5 years) with suspected CDI hospitalized at King Chulalongkorn Memorial Hospital, Bangkok, Thailand from December 2012 to February 2013, 22 were diagnosed with CDI by the gold standard PCR test for tcdA and tcdB, among whom 21 were positive by GDH EIA, accounting for a sensitivity of 95%. Of the 69 patients without CDI, GDH EIA was negative in 46 patients, accounting for a specificity of 67%. The positive predic- tive value (PPV), negative predictive value (NPV) and accuracy of GDH EIA was 48%, 98% and 74%, respectively, whereas sensitivity, specificity, PPV, NPV, and accuracy of cytotoxins A/B ELFA was 73%, 96%, 84%, 92% and 92%, respectively. Some 30% of specimens required the more expensive PCR assay. However, this two-step protocol detected 20% more patients with CDI than the currently used cytotoxins A/B ELFA method.
摘要。艰难梭菌感染（CDI）是泰国乃至全球最常见的医院感染之一。其临床症状范围从令人烦恼的腹泻到严重的危及生命的疾病。细胞毒素A/B酶联免疫荧光测定法（细胞毒素A/B ELFA）在我们研究所已被广泛使用，但一般认为其对CDI诊断的敏感性较低。本研究是对一种新型两步诊断算法的前瞻性评估，第一步是同时进行细胞毒素A/B ELFA和谷氨酸脱氢酶酶免疫测定法（GDH EIA）用于CDI检测，然后对结果不一致的样本进行tcdA和tcdB的聚合酶链反应（PCR）检测。2012年12月至2013年2月期间，在泰国曼谷朱拉隆功国王纪念医院住院的91例疑似CDI成年患者（37例男性和54例女性，平均年龄60.0±19.5岁）中，22例通过tcdA和tcdB的金标准PCR检测被诊断为CDI，其中21例GDH EIA呈阳性，敏感性为95%。在69例非CDI患者中，46例GDH EIA呈阴性，特异性为67%。GDH EIA的阳性预测值（PPV）、阴性预测值（NPV）和准确性分别为48%、98%和74%，而细胞毒素A/B ELFA的敏感性、特异性、PPV、NPV和准确性分别为73%、96%、84%、92%和92%。约30%的样本需要进行更昂贵的PCR检测。然而，这种两步检测方案比目前使用的细胞毒素A/B ELFA方法多检测出20%的CDI患者。
