BACKGROUND: There has been a growing interest in developing an appropriate laboratory diagnostic algorithm for Clostridium difficile, mainly as a result of increases in both the number and severity of cases of C difficile infection in the past decade. A C difficile diagnostic algorithm is necessary because diagnostic kits, mostly for the detection of toxins A and B or glutamate dehydrogenase (GDH) antigen, are not sufficient as stand-alone assays for optimal diagnosis of C difficile infection. In addition, conventional reference methods for C difficile detection (eg, toxigenic culture and cytotoxin neutralization [CTN] assays) are not routinely practiced in diagnostic laboratory settings.OBJECTIVE: To review the four-step algorithm used at Diagnostic Services of Manitoba sites for the laboratory diagnosis of toxigenic C difficile.RESULT: One year of retrospective C difficile data using the proposed algorithm was reported. Of 5695 stool samples tested, 9.1% (n=517) had toxigenic C difficile. Sixty per cent (310 of 517) of toxigenic C difficile stools were detected following the first two steps of the algorithm. CTN confirmation of GDH-positive, toxin A- and B-negative assays resulted in detection of an additional 37.7% (198 of 517) of toxigenic C difficile. Culture of the third specimen, from patients who had two previous negative specimens, detected an additional 2.32% (12 of 517) of toxigenic C difficile samples.DISCUSSION: Using GDH antigen as the screening and toxin A and B as confirmatory test for C difficile, 85% of specimens were reported negative or positive within 4 h. Without CTN confirmation for GDH antigen and toxin A and B discordant results, 37% (195 of 517) of toxigenic C difficile stools would have been missed. Following the algorithm, culture was needed for only 2.72% of all specimens submitted for C difficile testing.CONCLUSION: The overview of the data illustrated the significance of each stage of this four-step C difficile algorithm and emphasized the value of using CTN assay and culture as parts of an algorithm that ensures accurate diagnosis of toxigenic C difficile.

中文翻译：

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培养、抗原和毒素检测以及细胞毒素中和试验的组合，可实现最佳的艰难梭菌诊断测试。

背景：人们对开发合适的艰难梭菌实验室诊断算法越来越感兴趣，这主要是因为过去十年艰难梭菌感染病例的数量和严重程度都在增加。甲艰难梭菌诊断算法是必要的，因为诊断试剂盒，主要是用于检测毒素A和B或谷氨酸脱氢酶（GDH）抗原，不足以作为用于最佳诊断独立测定艰难梭菌感染。此外，艰难梭菌的常规参考方法检测（例如，产毒培养和细胞毒素中和 [CTN] 检测）在诊断实验室环境中并不常规实施。目的：审查曼尼托巴省诊断服务中心用于产毒艰难梭菌实验室诊断的四步算法。结果：报告了使用所提出算法的一年回顾性艰难梭菌数据。在测试的 5695 个粪便样本中，9.1% (n = 517) 含有产毒艰难梭菌。在算法的前两个步骤之后，检测到60%（517 个中的 310 个）产毒艰难梭菌粪便。GDH 阳性、毒素 A 和 B 阴性测定的 CTN 确认导致检测到额外的 37.7%（517 个中的 198 个）产毒艰难梭菌. 第三个标本的培养，来自先前两次阴性标本的患者，检测到另外 2.32%（517 个中的 12 个）产毒艰难梭菌样本。讨论：使用 GDH 抗原作为筛查，毒素 A 和 B 作为艰难梭菌的确认试验, 85% 的标本在 4 小时内报告为阴性或阳性。如果没有对 GDH 抗原和毒素 A 和 B 不一致结果的 CTN 确认，37%（517 个中的 195 个）的产毒艰难梭菌粪便将被遗漏。该算法以下，需要只有2.72％提交所有标本的文化的艰难testing.CONCLUSION：数据的概要说明了这四个步骤的每个阶段的意义难辨算法，并强调了使用 CTN 检测和培养作为确保产毒艰难梭菌准确诊断的算法的一部分的价值。