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Medline ® Abstracts for References 60-62

of 'Clostridium difficile infection in adults: Clinical manifestations and diagnosis'

60
TI
Effective detection of toxigenic Clostridium difficile by a two-step algorithm including tests for antigen and cytotoxin.
AU
Ticehurst JR, Aird DZ, Dam LM, Borek AP, Hargrove JT, Carroll KC
SO
J Clin Microbiol. 2006;44(3):1145.
 
We evaluated a two-step algorithm for detecting toxigenic Clostridium difficile: an enzyme immunoassay for glutamate dehydrogenase antigen (Ag-EIA) and then, for antigen-positive specimens, a concurrent cell culture cytotoxicity neutralization assay (CCNA). Antigen-negative results were>or = 99% predictive of CCNA negativity. Because the Ag-EIA reduced cell culture workload by approximately 75 to 80% and two-step testing was complete in<or = 3 days, we decided that this algorithm would be effective. Over 6 months, our laboratories' expenses were US dollar 143,000 less than if CCNA alone had been performed on all 5,887 specimens.
AD
Division of Medical Microbiology, The Johns Hopkins Hospital/Meyer B1-193, 600 North Wolfe St., Baltimore, Maryland 21287-7093, USA. jticehur@jhmi.edu
PMID
61
TI
Yield of stool culture with isolate toxin testing versus a two-step algorithm including stool toxin testing for detection of toxigenic Clostridium difficile.
AU
Reller ME, Lema CA, Perl TM, Cai M, Ross TL, Speck KA, Carroll KC
SO
J Clin Microbiol. 2007;45(11):3601. Epub 2007 Sep 5.
 
We examined the incremental yield of stool culture (with toxin testing on isolates) versus our two-step algorithm for optimal detection of toxigenic Clostridium difficile. Per the two-step algorithm, stools were screened for C. difficile-associated glutamate dehydrogenase (GDH) antigen and, if positive, tested for toxin by a direct (stool) cell culture cytotoxicity neutralization assay (CCNA). In parallel, stools were cultured for C. difficile and tested for toxin by both indirect (isolate) CCNA and conventional PCR if the direct CCNA was negative. The "gold standard" for toxigenic C. difficile was detection of C. difficile by the GDH screen or by culture and toxin production by direct or indirect CCNA. We tested 439 specimens from 439 patients. GDH screening detected all culture-positive specimens. The sensitivity of the two-step algorithm was 77% (95% confidence interval [CI], 70 to 84%), and that of culture was 87% (95% CI, 80 to 92%). PCR results correlated completely with those of CCNA testing on isolates (29/29 positive and 32/32 negative, respectively). We conclude that GDH is an excellent screening test and that culture with isolate CCNA testing detects an additional 23% of toxigenic C. difficile missed by direct CCNA. Since culture is tedious and also detects nontoxigenic C. difficile, we conclude that culture is most useful (i) when the direct CCNA is negative but a high clinical suspicion of toxigenic C. difficile remains, (ii) in the evaluation of new diagnostic tests for toxigenic C. difficile (where the best reference standard is essential), and (iii) in epidemiologic studies (where the availability of an isolate allows for strain typing and antimicrobial susceptibility testing).
AD
Division of Medical Microbiology, Department of Pathology, Johns Hopkins Medical Institutions, Baltimore, MD 21287, USA. mreller1@jhmi.edu
PMID
62
TI
Rapid and reliable diagnostic algorithm for detection of Clostridium difficile.
AU
Fenner L, Widmer AF, Goy G, Rudin S, Frei R
SO
J Clin Microbiol. 2008;46(1):328. Epub 2007 Nov 21.
 
We evaluated a two-step algorithm for detection of Clostridium difficile in 1,468 stool specimens. First, specimens were screened by an immunoassay for C. difficile glutamate dehydrogenase antigen (C.DIFF CHEK-60). Second, screen-positive specimens underwent toxin testing by a rapid toxin A/B assay (TOX A/B QUIK CHEK); toxin-negative specimens were subjected to stool culture. This algorithm allowed final results for 92% of specimens with a turnaround time of 4 h.
AD
Microbiology Laboratory, University Hospital Basel, Petersgraben 4, CH-4031 Basel, Switzerland.
PMID