Yuhashi Kazuhito, Yagihara Yuka, Misawa Yoshiki, Sato Tomoaki, Saito Ryoichi, Okugawa Shu, Moriya Kyoji
Department of Infection Control and Prevention, Faculty of Medicine, The University of Tokyo.
Department of Microbiology and Immunity, Graduate School of Health Care Sciences, Tokyo Medical and Dental University, Bunkyo-ku, Tokyo, Japan.
Infect Drug Resist. 2016 May 27;9:93-9. doi: 10.2147/IDR.S105429. eCollection 2016.
The enzyme immunoassay (EIA) has lower sensitivity for Clostridium difficile toxins A and B than the polymerase chain reaction in the diagnosis of C. difficile-associated diarrhea (CDAD). Furthermore, toxin positivity with EIA performed on C. difficile isolates from stool cultures may be observed even in patients with EIA glutamate dehydrogenase (GDH)-positive and toxin-negative stool specimens. It is unclear whether such patients should be treated as having CDAD.
The present study retrospectively compared patient characteristics, treatment, and diarrhea duration among three groups of patients who underwent stool EIA testing for CDAD diagnosis: a toxin-positive stool group (positive stool group; n=39); a toxin-negative stool/toxin-positive isolate group (discrepant negative/positive group, n=14); and a dual toxin-negative stool and isolate group (dual negative group, n=15). All cases included were confirmed to be GDH positive on EIA test.
Patients' backgrounds and comorbidities were not significantly different among three groups. No difference was observed among the three groups with regard to antimicrobial drug use before diarrhea onset. Treatment was received by 82.1% of the positive stool group compared to 7.1% of the discrepant positive/negative group and 0% of the dual negative group, while mean diarrhea duration was 10.6 days compared to 7.9 days (P=0.6006) and 3.4 days (P=0.0312), respectively.
Even without treatment, patients with toxin-negative stool specimens had shorter diarrhea duration than those with toxin-positive stool specimens even with toxin-positive isolates. These findings may suggest a limited need for CDAD treatment for GDH-positive patients and toxin-negative stool specimens.
在艰难梭菌相关性腹泻（CDAD）的诊断中，酶免疫测定（EIA）对艰难梭菌毒素A和B的敏感性低于聚合酶链反应。此外，即使在EIA检测谷氨酸脱氢酶（GDH）阳性且毒素阴性的粪便标本的患者中，对粪便培养分离出的艰难梭菌进行EIA检测时也可能观察到毒素阳性。尚不清楚此类患者是否应被视为患有CDAD。
本研究回顾性比较了三组因CDAD诊断而接受粪便EIA检测的患者的特征、治疗情况和腹泻持续时间：毒素阳性粪便组（阳性粪便组；n = 39）；毒素阴性粪便/毒素阳性分离株组（不一致阴性/阳性组，n = 14）；以及双重毒素阴性粪便和分离株组（双重阴性组，n = 15）。纳入的所有病例在EIA检测中均被确认为GDH阳性。
三组患者的背景和合并症无显著差异。腹泻发作前使用抗菌药物的情况在三组之间未观察到差异。阳性粪便组82.1%的患者接受了治疗，相比之下，不一致阳性/阴性组为7.1%，双重阴性组为0%，而平均腹泻持续时间分别为10.6天、7.9天（P = 0.6006）和3.4天（P = 0.0312）。
即使不进行治疗，毒素阴性粪便标本的患者腹泻持续时间也比毒素阳性粪便标本的患者短，即使后者分离出毒素阳性菌株。这些发现可能表明，对于GDH阳性且粪便标本毒素阴性的患者，CDAD治疗的必要性有限。
