Unit of Infectious Diseases, Hospital Universitario "12 de Octubre," Instituto de Investigación Hospital "12 de Octubre" (i+12), School of Medicine, Universidad Complutense, Madrid, Spain
Department of Microbiology, Hospital Universitario "12 de Octubre," Instituto de Investigación Hospital "12 de Octubre" (i+12), School of Medicine, Universidad Complutense, Madrid, Spain.
J Clin Microbiol. 2019 Jan 30;57(2). doi: 10.1128/JCM.01125-18. Print 2019 Feb.
The objective of the present study was to evaluate the value of the PCR cycle threshold ( ) for predicting the recurrence/severity of infection compared to that of toxin detection plus clinical variables. First episodes of infection (CDI) diagnosed during 2015 at our institution were included. Samples were tested for glutamate dehydrogenase (GDH) and toxin A/B by use of a single enzyme immunoassay (EIA). The Xpert PCR assay was performed on GDH-positive samples. Medical data were reviewed by investigators blinded to diagnostic results for comparison of patients with and without recurrence or a poor outcome (severe/severe-complicated CDI episodes and all-cause death). We generated two sets of predictive models by incorporating the presence of a positive toxin EIA ("EIA-including model") or the optimal PCR cutoff value ("PCR-including model") into the clinical variables. Among 227 episodes of CDI included in the study, the rates of recurrence and poor outcome were 15.8% and 30.8%, respectively. The mean PCR was lower for episodes with recurrence (24.00 ± 3.28 versus 26.02 ± 4.54; = 0.002) or a poor outcome (24.9 ± 4.24 versus 26.05 ± 4.47; = 0.07). The optimal cutoff value for recurrence was 25.65 (sensitivity, 77.8% [95% confidence interval {CI}, 60.9 to 89.9]; and specificity, 46.6% [95% CI, 39.4 to 53.9]). The area under the receiver operator characteristics curve (auROC) for the "PCR-including model" was similar to that for the "EIA-including model" (0.785 versus 0.775, respectively). The optimal PCR value for poor outcome was 27.55 (sensitivity, 78.6% [95% CI, 67.1 to 87.5]; and specificity, 35.7% [95% CI, 28.2 to 43.7]). The auROC of the "PCR-including model" was again similar to that of the "EIA-including model" (0.804 versus 0.801). Despite the inverse correlation between PCR and the risk of CDI recurrence/severity, this determination does not meaningfully increase the predictive value of clinical variables plus toxin EIA.
本研究旨在评估聚合酶链反应（PCR）循环阈值（）在预测感染复发/严重程度方面的价值，与毒素检测和临床变量相比。纳入 2015 年我院诊断的首次艰难梭菌感染（CDI）病例。采用单酶免疫法（EIA）检测谷氨酸脱氢酶（GDH）和毒素 A/B。GDH 阳性样本进行 Xpert PCR 检测。研究者对医疗数据进行了回顾，以比较复发或预后不良（严重/严重复杂 CDI 发作和全因死亡）患者的情况。我们通过将阳性毒素 EIA 存在纳入（“EIA 纳入模型”）或最佳 PCR 截止值纳入（“PCR 纳入模型”），生成了两套预测模型。在纳入的 227 例 CDI 发作中，复发和预后不良的发生率分别为 15.8%和 30.8%。复发（24.00 ± 3.28 与 26.02 ± 4.54； = 0.002）或预后不良（24.9 ± 4.24 与 26.05 ± 4.47； = 0.07）的病例的平均 PCR 值较低。复发的最佳截止值为 25.65（敏感性 77.8%[95%置信区间 {CI}，60.9 至 89.9]；特异性 46.6%[95% CI，39.4 至 53.9]）。“PCR 纳入模型”的受试者工作特征曲线（auROC）与“EIA 纳入模型”相似（分别为 0.785 和 0.775）。预后不良的最佳 PCR 值为 27.55（敏感性 78.6%[95% CI，67.1 至 87.5]；特异性 35.7%[95% CI，28.2 至 43.7]）。“PCR 纳入模型”的 auROC 再次与“EIA 纳入模型”相似（分别为 0.804 和 0.801）。尽管 PCR 值与 CDI 复发/严重程度的风险呈负相关，但这一决定并不能显著提高临床变量加毒素 EIA 的预测价值。
