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Diagnosing Clostridium difficile-associated diarrhea using enzyme immunoassay: the clinical significance of toxin negativity in glutamate dehydrogenase-positive patients

Authors Yuhashi K, Yagihara Y, Miasawa Y, Sato T, Saito R, Okugawa S, Moriya K

Received 30 January 2016

Accepted for publication 7 April 2016

Published 27 May 2016 Volume 2016:9 Pages 93—99


Checked for plagiarism Yes

Review by Single-blind

Peer reviewers approved by Dr Lucy Goodman

Peer reviewer comments 3

Editor who approved publication: Professor Suresh Antony

Kazuhito Yuhashi,1 Yuka Yagihara,1 Yoshiki Misawa,1 Tomoaki Sato,1 Ryoichi Saito,2 Shu Okugawa,1 Kyoji Moriya1

1Department of Infection Control and Prevention, Faculty of Medicine, The University of Tokyo, 2Department of Microbiology and Immunity, Graduate School of Health Care Sciences, Tokyo Medical and Dental University, Bunkyo-ku, Tokyo, Japan

Purpose: 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.
Methods: 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.
Results: 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.
Conclusion: 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.

Clostridium difficile toxin, diarrhea duration, treatment

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