title: High prevalence of toxin A-negative toxin B-positive Clostridium difficile in hospitalized patients with gastrointestinal disease.
abstract: The incidence of Clostridium difficile toxin A-negative toxin B-positive in hospitalized patients with severe gastrointestinal disease was evaluated. Of 530 stool specimens tested in parallel by two immunoassay tests, Tox A and Tox A/B (TechLab, Inc., Blacksburg, VA), 422 produced negative results on both tests. One hundred eight specimens (20.4%) tested positive by Tox A/B assay, and only 47 of them were also positive by Tox A. The 61 specimens with discrepant results were confirmed to be positive for toxin B by tissue culture cytotoxicity assay. Furthermore, 3 of the 422 specimens that were negative by enzyme immunoassay tested positive by cytotoxicity assay. The sensitivity and specificity of the Tox A/B test were 95.3% and 100%, respectively, with negative and positive predictive values of 99.3% and 100%, respectively, and a correlation rate of 99.4%. The high prevalence (56.5%) of specimens from symptomatic patients having detectable toxin B, but undetectable toxin A emphasizes the importance of using diagnostic tests that include toxin B. Furthermore, our data support the potential role of toxin B in the pathogenesis of toxigenic Clostridium difficile.
authors.affiliation: Department of Microbiology, Rabin Medical Center, Beilinson Campus, Petah Tiqva and Sackler Faculty of Medicine, Tel Aviv University, Israel. zsamra@clalit.org.il
authors.forename: Zmira
authors.initials: Z
authors.lastname: Samra
authors.forename: Smadar
authors.initials: S
authors.lastname: Talmor
authors.forename: Judi
authors.initials: J
authors.lastname: Bahar
mesh_terms: D001426:Bacterial Proteins; D001427:Bacterial Toxins / Q000032:analysis*; D002648:Child; D016360:Clostridioides difficile / Q000302:isolation & purification; D004761:Enterocolitis, Pseudomembranous / Q000453:epidemiology / Q000382:microbiology*; D004768:Enterotoxins / Q000032:analysis*; D006760:Hospitalization; D006801:Humans; D007124:Immunoenzyme Techniques / Q000379:methods; D015994:Incidence; D007557:Israel / Q000453:epidemiology; D015995:Prevalence; D012680:Sensitivity and Specificity
chemical_list: D001426:Bacterial Proteins; D001427:Bacterial Toxins; D004768:Enterotoxins; C041348:tcdA protein, Clostridium difficile; C031815:toxB protein, Clostridium difficile