Evaluation of the cepheid Xpert Clostridium difficile Epi assay for diagnosis of Clostridium difficile infection and typing of the NAP1 strain at a cancer hospital Journal Article


Authors: Babady, N. E.; Stiles, J.; Ruggiero, P.; Khosa, P.; Huang, D.; Shuptar, S.; Kamboj, M.; Kiehn, T. E.
Article Title: Evaluation of the cepheid Xpert Clostridium difficile Epi assay for diagnosis of Clostridium difficile infection and typing of the NAP1 strain at a cancer hospital
Abstract: Clostridium difficile is the most common cause of health care-associated diarrhea. Accurate and rapid diagnosis is essential to improve patient outcome and prevent disease spread. We compared our two-step diagnostic algorithm, an enzyme immunoassay for glutamate dehydrogenase (GDH) followed by the cytotoxin neutralization test (CYT) with a turnaround time of 24 to 48 h, versus the Cepheid Xpert C. difficile Epi assay, a PCR-based assay with a turnaround time of <1 h. In the first phase of the study, only GDH-positive stool samples were tested by both CYT and Xpert PCR. Discordant results were resolved by toxigenic culture. In the second phase, all stool samples were tested by GDH and Xpert PCR. Only GDH-positive stools were further tested by CYT. Genotypic characterization of 45 Xpert PCR-positive stools was performed by sequencing of the tcdC gene and PCR ribotyping. In phase 1, the agreement between the GDH-CYT and the GDH-Xpert PCR was 72%. The sensitivities and specificities of GDH-CYT and GDH-Xpert PCR were 57% and 97% and 100% and 97%, respectively. In phase 2, the agreement between GDH-CYT and Xpert PCR alone was 95%. As in phase 1, sensitivity of the Xpert PCR was higher than that of the GDH-CYT. The correlation between PCR-ribotyping, sequencing, and Xpert PCR for detection of NAP1 strains was excellent (>90%). The excellent sensitivity and specificity and the rapid turnaround time of the Xpert PCR assay as well as its strain-typing capability make it an attractive option for diagnosis of C. difficile infection. Copyright © 2010, American Society for Microbiology. All Rights Reserved.
Keywords: controlled study; gene sequence; major clinical study; sensitivity and specificity; polymerase chain reaction; genotype; bacterial strain; enzyme immunoassay; bacterial proteins; cancer care facilities; clostridium difficile infection; enzyme-linked immunosorbent assay; bacteriological techniques; clostridium difficile; repressor proteins; feces; cross infection; feces analysis; cytotoxin; glutamate dehydrogenase; ribotyping; clostridium infections
Journal Title: Journal of Clinical Microbiology
Volume: 48
Issue: 12
ISSN: 0095-1137
Publisher: American Society for Microbiology  
Date Published: 2010-12-01
Start Page: 4519
End Page: 4524
Language: English
DOI: 10.1128/jcm.01648-10
PUBMED: 20943860
PROVIDER: scopus
PMCID: PMC3008447
DOI/URL:
Notes: --- - "Export Date: 20 April 2011" - "CODEN: JCMID" - "Source: Scopus"
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MSK Authors
  1. Perminder Khosa
    3 Khosa
  2. Ngolela Esther Babady
    171 Babady
  3. Ying Chiang Huang
    43 Huang
  4. Mini Kamboj
    158 Kamboj
  5. Timothy E Kiehn
    100 Kiehn
  6. Jeffrey Stiles
    26 Stiles