Original Article
Applicability of commercial multiplex kit for the diagnosis of: a multicenter investigation Clostridium difficile infections
Shi Wu, Fenfen Zhou, Yuxing Ni, Yunjian Hu, Ye Chen, Yunsong Yu, Haihui Huang
Published 2019-08-11
Cite as Chin J Lab Med, 2019, 42(8): 674-678. DOI: 10.3760/cma.j.issn.1009-9158.2019.08.017
Abstract
ObjectiveTo evaluate the performance of Xpert C. difficile multiplex real-time PCR assay for diagnosis of Clostridium difficile infections in Chinese hospital settings.
MethodsThis study was performed in Huashan Hospital, Ruijin Hospital, Beijing Hospital, Nanfang Hospital and Sir Run Run Shaw Hospital using a standard study protocol. Unique unformed stools from patients with acute hospital-acquired diarrhea were simultaneously analyzed by toxigenic anaerobic cultures and the Xpert C. difficile assay. All specimens displaying discordant results between the Xpert assay and toxigenic culture were sent for Sanger tcdB gene sequencing. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), total concordance rate, and 95% confidence interval (CI) were calculated before and after resolution of discordant results using SAS 9.3.
ResultsA total of 745 stool specimens were collected and 46 were excluded due to failure of C. difficile recovery. The remaining 699 specimens were included. Compared to the results of toxigenic culture, the sensitivity, specificity, PPV, and NPV of Xpert C. difficile assay were 94.1% (144/153)(95%CI:89.1%-97.3%), 93.2% (509/546)(95%CI:96.7%-99.2%), 79.6% (144/181)(95%CI: 72.9%-85.2%)and 98.3% (509/518)(95%CI: 96.7%-99.2%), respectively. Both methods had a Kappa of 0.819. Xpert C. difficile assay showed sensitivity of 98.4%(62/63) (95% CI: 90.3%-99.9%) and specificity of 93.2%(509/546) (95% CI: 90.8%-95.2%) for toxin A-negative toxin B-positive strains. After the discordant results resolved by tcdB gene sequencing, PCR assay provided better performance with high sensitivity, specificity, positive predictive value, and negative predictive value [98.8% (171/173), 98.1% (516/526), 94.5% (171/181) and 99.6% (516/518), respectively].
ConclusionsCompared to the results of toxigenic culture, the sensitivity, specificity and NPV of Xpert C. difficile assay were 94.1% (144/153) and 93.2% (509/546), respectively. With the results available within 1 h, Xpert C. difficile assay provides prompt and precise laboratory diagnosis in Chinese clinical settings.
Key words:
Clostridium difficile; Clostridium infections; Real-time polymerase chain reaction
Contributor Information
Shi Wu
Institute of Antibiotics, Huashan Hospital, Fudan University
Key Laboratory of Clinical Pharmacology of Antibiotics, National Health and Family Planning Commission Shanghai 200040, China
Fenfen Zhou
Department of Microbial Pathogenesis, University of Maryland School of Dentistry, Baltimore 21201, USA
Yuxing Ni
Clinical Microbiology, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai 200025, China
Yunjian Hu
Clinical Laborary, Beijing Hospital, Beijing 100730, China
Ye Chen
Department of Gastroenterology Nanfang Hospital, Southern Medical University, Guangzhou 510515, China
Yunsong Yu
Deptment of Infections Diseases, Sir Run RunShaw Hospital, Zhejiang University, Hangzhou 310016, China
Haihui Huang
Institute of Antibiotics, Huashan Hospital, Fudan University
Key Laboratory of Clinical Pharmacology of Antibiotics, National Health and Family Planning Commission Shanghai 200040, China
