Comparison of two rapid assays for Clostridium difficile Common antigen and a C difficile toxin A/B assay with the cell culture neutralization assay.
We compared 3 rapid assays for Clostridium difficile with a cell culture cytotoxicity neutralization assay (CCNA). Of 600 stool samples, 46 were positive for toxigenic C difficile. Both rapid common antigen assays were highly sensitive (91.3%-100%) and, therefore, were appropriate screening tests. The rapid toxin assay had poor sensitivity (61%) but excellent specificity (99.3%). Testing stools for glutamate dehydrogenase (step 1) and those positive with a rapid toxin assay (step 2) would correctly classify 81% of submitted specimens within 2 hours, including during periods of limited staffing (evenings, nights, and weekends). CCNA could then be used as a third step to test rapid toxin-negative samples, thereby providing a final result for the remaining 19% of samples by 48 to 72 hours. The use of rapid assays as outlined could enhance timely diagnosis of C difficile.
Reller
Megan E
ME
Division of Medical Microbiology, Department of Pathology, The Johns Hopkins Medical Institutions, Baltimore, MD 21205, USA.
Alcabasa
Romina C
RC
Lema
Clara A
CA
Carroll
Karen C
KC
D000942:Antigens, Bacterial / Q000032:analysis*; D001426:Bacterial Proteins / Q000032:analysis* / Q000276:immunology; D001427:Bacterial Toxins / Q000032:analysis* / Q000276:immunology; D001431:Bacteriological Techniques / Q000379:methods*; D002478:Cells, Cultured; D016360:Clostridioides difficile / Q000302:isolation & purification*; D004768:Enterotoxins / Q000032:analysis* / Q000276:immunology; D005243:Feces / Q000201:enzymology / Q000382:microbiology*; D005347:Fibroblasts / Q000166:cytology / Q000382:microbiology; D052816:Foreskin / Q000166:cytology / Q000382:microbiology; D005969:Glutamate Dehydrogenase / Q000032:analysis / Q000378:metabolism; D006801:Humans; D008297:Male; D009500:Neutralization Tests / Q000379:methods; D011237:Predictive Value of Tests
D000942:Antigens, Bacterial; D001426:Bacterial Proteins; D001427:Bacterial Toxins; D004768:Enterotoxins; C041348:tcdA protein, Clostridium difficile; C031815:toxB protein, Clostridium difficile; D005969:Glutamate Dehydrogenase