Kyorin University Graduate School of Medicine, Tokyo, Japan.
Department of Clinical Laboratory, Tokai University Hospital, Kanagawa, Japan.
J Clin Microbiol. 2018 Nov 27;56(12). doi: 10.1128/JCM.00555-18. Print 2018 Dec.
In recent years, the diagnostic method of choice for infection (CDI) is a rapid enzyme immunoassay in which glutamate dehydrogenase (GDH) antigen and toxin can be detected ( Quik Chek Complete; Alere Inc.) (Quik Chek). However, the clinical significance remains unclear in cases that demonstrate a positive result for GDH antigen and are negative for toxin. In this study, we used the Quik Chek test kit on fecal samples, with an additional toxin detection step using a toxigenic culture assay for the aforementioned cases. CDI risk factors were assessed among the 3 groups divided by the Quik Chek test results. The study involved 1,565 fecal samples from patients suspected to have CDI who were hospitalized during the period of April 2012 to March 2014. The 3 groups were defined as follows: both GDH antigen positive and toxin positive (by Quik Chek test) (toxin-positive [TP] group, = 109), both GDH antigen and toxin negative (toxin-negative [TN] group, = 111), and positive only for GDH antigen but toxin positive with subsequent toxigenic culture (toxigenic culture [TC] group, = 72). The gender, age, number of hospitalization days, white blood cell (WBC) counts, serum albumin levels, body mass index (BMI), fecal consistency, and use of antibacterials and proton pump inhibiters (PPIs) were analyzed. The positive rate for the fecal direct Quik Chek test was 7.0% (109/1,565 cases). However, toxigenic culture assays using the Quik Chek test for only the GDH-antigen-positive/toxin-negative samples were 35.3% positive (72/204 cases). As a result, the true positive rate for toxin detection was estimated to be 11.6% (181/1,565 cases). Moreover, significant differences ( < 0.05) in the number of hospitalization days (>50 days), WBC counts (>10,000 WBCs/μl), and use of PPIs comparing the TN, TP, and TC groups, were observed. The odds ratios (ORs) for the development of CDI were 1.61 (95% confidence interval [CI], 0.94 to 2.74) and 2.98 (95% CI, 1.59 to 5.58) for numbers of hospitalization days, 2.16 (95% CI, 1.24 to 3.75) and 2.24 (95% CI, 1.21 to 4.14) for WBC counts, and 9.03 (95% CI, 4.9 to 16.6) and 9.15 (95% CI, 4.59 to 18.2) for use of PPIs in the TP and TC groups, respectively. These findings demonstrated that the use of PPIs was a significant risk factor for CDI development. Moreover, antibacterials such as carbapenems, cephalosporins, and fluoroquinolones were demonstrated to be risk factors. In conclusion, identification of the TC group of patients is thought to be important, as this study demonstrates that this group bears the same high risk of developing CDI as the TP group.
近年来，感染（CDI）的诊断方法是一种快速酶免疫测定法，其中可以检测谷氨酸脱氢酶（GDH）抗原和毒素（Quik Chek Complete；Alere Inc.）（Quik Chek）。然而，在GDH 抗原阳性而毒素阴性的情况下，其临床意义仍不清楚。在这项研究中，我们使用了 Quik Chek 试剂盒对粪便样本进行检测，并使用产毒培养检测法对上述情况进行了毒素检测。我们评估了根据 Quik Chek 检测结果将患者分为 3 组的情况下的 CDI 危险因素。该研究涉及 2012 年 4 月至 2014 年 3 月期间住院的疑似 CDI 患者的 1565 份粪便样本。3 组定义如下：GDH 抗原和毒素均阳性（通过 Quik Chek 检测）（毒素阳性[TP]组，= 109）、GDH 抗原和毒素均阴性（毒素阴性[TN]组，= 111）和仅 GDH 抗原阳性但毒素阳性，随后进行产毒培养（产毒培养[TC]组，= 72）。分析了性别、年龄、住院天数、白细胞（WBC）计数、血清白蛋白水平、体重指数（BMI）、粪便稠度以及使用抗菌药物和质子泵抑制剂（PPIs）的情况。粪便直接 Quik Chek 检测的阳性率为 7.0%（109/1565 例）。然而，使用 Quik Chek 试验仅对 GDH-抗原阳性/毒素阴性样本进行产毒培养的检测阳性率为 35.3%（72/204 例）。因此，毒素检测的真实阳性率估计为 11.6%（181/1565 例）。此外，在住院天数（>50 天）、白细胞计数（>10,000 白细胞/μl）和使用 PPI 方面，TN、TP 和 TC 组之间观察到显著差异（<0.05）。CDI 发展的优势比（OR）分别为 1.61（95%置信区间[CI]，0.94 至 2.74）和 2.98（95%CI，1.59 至 5.58）住院天数，2.16（95%CI，1.24 至 3.75）和 2.24（95%CI，1.21 至 4.14）白细胞计数，以及 9.03（95%CI，4.9 至 16.6）和 9.15（95%CI，4.59 至 18.2）使用 PPI 的 TP 和 TC 组，分别。这些发现表明，使用 PPI 是 CDI 发展的重要危险因素。此外，抗菌药物如碳青霉烯类、头孢菌素类和氟喹诺酮类也被证明是危险因素。总之，认为识别 TC 组患者很重要，因为本研究表明该组与 TP 组一样具有很高的 CDI 发展风险。
