This Article
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Right arrow Citation Map
Services
Right arrow E-mail this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrowReprints and Permissions
Right arrow Copyright Information
Right arrow Books from ASM Press
Right arrow MicrobeWorld
Google Scholar
Right arrow Articles by Shin, B.-M.
Right arrow Articles by Songer, J. G.
PubMed
Right arrow PubMed Citation
Right arrow Articles by Shin, B.-M.
Right arrow Articles by Songer, J. G.

 Previous Article  |  Next Article 

Journal of Clinical Microbiology, September 2009, p. 2952-2956, Vol. 47, No. 9
0095-1137/09/$08.00+0     doi:10.1128/JCM.00609-09
Copyright © 2009, American Society for Microbiology. All Rights Reserved.

Algorithm Combining Toxin Immunoassay and Stool Culture for Diagnosis of Clostridium difficile Infection{triangledown}

Bo-Moon Shin,1 Eun Young Kuak,1 Eun Joo Lee,1 and J. Glenn Songer2*

Department of Laboratory Medicine, Sanggye Paik Hospital, Inje University, Seoul, South Korea,1 Department of Veterinary Science and Microbiology, The University of Arizona, Tucson, Arizona2

Received 26 March 2009/ Returned for modification 14 May 2009/ Accepted 13 July 2009

Enzyme immunoassays (EIA) to detect glutamate dehydrogenase or toxins A (TcdA) and B (TcdB), a cytotoxicity assay, and bacteriologic culture have disadvantages when applied individually to diagnosis of Clostridium difficile infections. Stool specimens (n = 1,596) were subjected to toxin detection via an enzyme-linked fluorescent immunoassay (ELFA; Vidas CDAB assay) and bacteriologic culture for toxigenic C. difficile in a three-step algorithm with additional toxigenic culture. Isolates (n = 163) from ELFA-negative stool specimens were examined via ELFA for toxin production. We amplified tcdA and tcdB from C. difficile isolates and tcdB from stool specimens that were ELFA positive or equivocal and culture negative, and we compared the results to those obtained with the three-step algorithm. More than 26% of stool specimens (419/1,596) were culture positive, yielding 248 isolates (59.2%) with both toxin genes (tcdA- and tcdB-positive isolates), 88 isolates (21.0%) with either tcdA or tcdB, and 83 (19.8%) that had no toxin genes (tcdA- and tcdB-negative isolates). Among 49 (culture-negative/ELFA-positive or -equivocal) stool specimens, 53.1% (26/49) represented tcdB-positive isolates. Therefore, the total number of PCR-positive cases was 362, and 27.1% (98/362) of these were detected through toxigenic culture. The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were 63.3%, 96.7%, 90.5%, and 92.4% (ELFA alone); 92.8%, 93.3%, 80.2%, and 97.8% (culture); and 70.7%, 91.4%, 95.5%, and 100% (three-step algorithm ELFA and bacterial culture with toxigenic culture), respectively, with culture and PCR for tcdA and tcdB as the standards. Thus, sensitivity and specificity were highest using culture and ELFA, respectively, but we recommend the three-step algorithm comprising EIA to detect both toxins and toxigenic culture for C. difficile as a practical method for achieving better PPV and NPV.

* Corresponding author. Mailing address: Department of Veterinary Science and Microbiology, The University of Arizona, 1117 East Lowell Street, Tucson, AZ 85721. Phone: (520) 621-2962. Fax: (520) 621-6366. E-mail: gsonger{at}u.arizona.edu

{triangledown} Published ahead of print on 22 July 2009.

Journal of Clinical Microbiology, September 2009, p. 2952-2956, Vol. 47, No. 9
0095-1137/09/$08.00+0     doi:10.1128/JCM.00609-09
Copyright © 2009, American Society for Microbiology. All Rights Reserved.





Copyright © 2010 by the American Society for Microbiology.   For an alternate route to Journals.ASM.org, visit: http://intl-journals.asm.org | More Info»