scholarly journals Combination of Culture, Antigen and Toxin Detection, and Cytotoxin Neutralization Assay for OptimalClostridium difficileDiagnostic Testing

2013 ◽  
Vol 24 (2) ◽  
pp. 89-92 ◽  
Author(s):  
Michelle J Alfa ◽  
Shadi Sepehri
Keyword(s):  
Diagnostic Algorithm ◽  
Laboratory Diagnosis ◽  
Neutralization Assay ◽  
Confirmatory Test ◽  
Toxin A ◽  
Diagnostic Laboratory ◽  
Toxigenic Culture ◽  
Stool Samples ◽  
Step Algorithm ◽  
One Year

BACKGROUND: There has been a growing interest in developing an appropriate laboratory diagnostic algorithm forClostridium difficile, mainly as a result of increases in both the number and severity of cases ofC difficileinfection in the past decade. AC difficilediagnostic algorithm is necessary because diagnostic kits, mostly for the detection of toxins A and B or glutamate dehydrogenase (GDH) antigen, are not sufficient as stand-alone assays for optimal diagnosis ofC difficileinfection. In addition, conventional reference methods forC difficiledetection (eg, toxigenic culture and cytotoxin neutralization [CTN] assays) are not routinely practiced in diagnostic laboratory settings.OBJECTIVE: To review the four-step algorithm used at Diagnostic Services of Manitoba sites for the laboratory diagnosis of toxigenicC difficile.RESULT: One year of retrospectiveC difficiledata using the proposed algorithm was reported. Of 5695 stool samples tested, 9.1% (n=517) had toxigenicC difficile. Sixty per cent (310 of 517) of toxigenicC difficilestools were detected following the first two steps of the algorithm. CTN confirmation of GDH-positive, toxin A- and B-negative assays resulted in detection of an additional 37.7% (198 of 517) of toxigenicC difficile. Culture of the third specimen, from patients who had two previous negative specimens, detected an additional 2.32% (12 of 517) of toxigenicC difficilesamples.DISCUSSION: Using GDH antigen as the screening and toxin A and B as confirmatory test forC difficile, 85% of specimens were reported negative or positive within 4 h. Without CTN confirmation for GDH antigen and toxin A and B discordant results, 37% (195 of 517) of toxigenicC difficilestools would have been missed. Following the algorithm, culture was needed for only 2.72% of all specimens submitted forC difficiletesting.CONCLUSION: The overview of the data illustrated the significance of each stage of this four-stepC difficilealgorithm and emphasized the value of using CTN assay and culture as parts of an algorithm that ensures accurate diagnosis of toxigenicC difficile.

scholarly journals Evaluation of the Use of Rectal Swabs for Laboratory Diagnosis ofClostridium difficileInfection

2018 ◽  
Vol 56 (7) ◽  
Author(s):  
N. Jazmati ◽  
E. Kirpal ◽  
E. Piepenbrock ◽  
Y. Stelzer ◽  
M. J. G. T. Vehreschild ◽  
...  
Keyword(s):  
Liquid Medium ◽  
Detection Rate ◽  
Laboratory Diagnosis ◽  
Toxin A ◽  
Suitable Alternative ◽  
Content Type ◽  
Toxigenic Culture ◽  
Rectal Swabs ◽  
Stool Samples ◽  
The Impact

ABSTRACTFor the diagnosis ofClostridium difficileinfection (CDI), microbiological testing is almost always accomplished through the analysis of stool specimens. We evaluated the performances of rectal swabs with liquid transport medium (FS) and nylon flocked dry swabs for the detection ofC. difficile. Additionally, the impact on the diagnostic yield of storing swabs at −80°C for up to 3 months was evaluated. Sixty clinical stool samples positive forC. difficileby PCR were used for simulating rectal swabbing. FS and dry swabs were dipped into the stool and tested by PCR directly after swabbing at 1 and 3 months after storage at −80°C. Stool and the liquid medium of FS were additionally tested by a combination of glutamate dehydrogenase antigen (GDH) testing and toxin A/B enzyme immunoassay (EIA), as well as by toxigenic culture (TC). Using dry swabs, the PCR-based detection rate ofC. difficilewas equal to the rate using stool samples (30/30 [100%]), whereas the detection rate in FS was significantly lower (25/30 [83.2%];P= 0.019). The sensitivities of FS for detectingC. difficileby PCR, TC, GDH testing, and toxin A/B EIA were 83.3%, 85.7%, 88%, and 68.9%, respectively. Storage of swabs at −80°C had no impact on the detection rate. FS cannot replace stool samples in the two-step laboratory diagnosis of CDI, as the sensitivities were too low, probably due to diluting effects of the fecal sample in the liquid medium. For simple PCR-based detection ofC. difficile, dry swabs proved to be a suitable alternative to the use of stool samples.

scholarly journals Diagnostic Algorithm Using a Sensitive Broth Culture Method for Detection ofClostridium difficileToxin from Stool Samples

2009 ◽  
Vol 20 (4) ◽  
pp. e135-e138
Author(s):  
Paul Bayardelle
Keyword(s):  
Screening Method ◽  
Diagnostic Algorithm ◽  
High Sensitivity ◽  
Culture Method ◽  
Neutralization Assay ◽  
Broth Culture ◽  
Increased Sensitivity ◽  
Stool Samples ◽  
Step Algorithm ◽  
Low Sensitivity

BACKGROUND: The two-step glutamate dehydrogenase antigencytotoxicity neutralization assay algorithm has been found to be reliable for the diagnosis of toxigenicClostridium difficile. However, the high sensitivity of the screening method is compromised by the relative low sensitivity of the second step, the direct cytotoxin neutralization assay (DCNA) using a fecal filtrate. The objective of the present study was to compare the DCNA with an indirect cytotoxin neutralization assay (ICNA).METHODS: For ICNA, the cytotoxin B ofC difficilewas obtained from a broth culture of the stools and neutralized according to a standard cytotoxin assay using MRC-5 fibroblast cells.RESULTS: A total of 923 stool specimens from adults were tested during a three-month period from June to August 2008. The prevalence of toxigenicC difficilewas 13.5%. The sensitivity of the two-step algorithm was 88%. With the ICNA, 12% toxigenicC difficilewere detected that were missed by DCNA.CONCLUSIONS: The use of broth for the ICNA is convenient, and results in increased sensitivity of detection of toxigenicC difficile. It can be implemented in routine diagnosis.

scholarly journals Experience with the Urinary Tetrasaccharide Metabolite for Pompe Disease in the Diagnostic Laboratory

Metabolites ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 446
Author(s):  
Jennifer T. Saville ◽  
Maria Fuller
Keyword(s):  
Pompe Disease ◽  
Late Onset ◽  
Reference Interval ◽  
Laboratory Diagnosis ◽  
Reference Intervals ◽  
Confirmatory Test ◽  
Diagnostic Laboratory ◽  
Age Related ◽  
Initial Drop ◽  
Monitoring Treatment

Following clinical indications, the laboratory diagnosis of the inherited metabolic myopathy, Pompe disease (PD), typically begins with demonstrating a reduction in acid alpha-glucosidase (GAA), the enzyme required for lysosomal glycogen degradation. Although simple in concept, a major challenge is defining reference intervals, as even carriers can have reduced GAA, and pseudodeficiencies complicate interpretation. Here, we developed a mass spectrometric assay for quantification of a urinary glycogen metabolite (tetrasaccharide) and reported on its utility as a confirmatory test for PD in a diagnostic laboratory. Using two age-related reference intervals, eight returned tetrasaccharide concentrations above the calculated reference interval but did not have PD, highlighting non-specificity. However, retrospective analysis revealed elevated tetrasaccharide in seven infantile-onset (IOPD) cases and sixteen late-onset (LOPD) cases, and normal concentrations in one heterozygote. Prospective tetrasaccharide analysis in nine individuals with reduced GAA confirmed IOPD in one, LOPD in six and identified two heterozygotes. Using this metabolite as a biomarker of therapeutic response was not overly informative; although most patients showed an initial drop following therapy initiation, tetrasaccharide concentrations fluctuated considerably and remained above reference intervals in all patients. While useful as a confirmation of PD, its utility as a biomarker for monitoring treatment warrants further investigation.

scholarly journals Evaluation of LIAISON® C. difficile glutamate dehydrogenase and LIAISON® C. difficile toxin A and B in Copan FecalSwabTM samples in a three-step algorithm for the diagnosis of Clostridium difficile infection

2015 ◽  
Vol 30 (1) ◽  
Author(s):  
Massimo Oggioni ◽  
Alessandra Bielli ◽  
Alice Nava ◽  
Daniela Adele Pia Campisi
Keyword(s):  
Clostridium Difficile ◽  
Glutamate Dehydrogenase ◽  
Laboratory Diagnosis ◽  
Binary Toxin ◽  
Common Antigen ◽  
Molecular Test ◽  
Toxin A ◽  
Large Numbers ◽  
Step Algorithm ◽  
Short Time

The presumptive laboratory diagnosis of <em>Clostridium</em> <em>difficile</em> infection is achieved by the means of the detection of a common antigen (glutamate dehydrogenase, GDH) in stool, then confirming the positives either by the detection of toxins A and B or by a molecular test for the detection of pathogenicity <em>locus</em>, encoding for the two toxins and for the binary toxin. A fully automated chemiluminescence system for the GDH antigen (LIAISON® C. difficile GDH) and for the detection of toxins A and B (LIAISON® C. difficile Toxin A and B) (DiaSorin, Gerenzano, Italy) allows for the performance of these tests on large numbers of samples in a short time, ensuring the traceability of the data.

scholarly journals Evaluation of Two Rapid Assays for Detection ofClostridium difficile Toxin A in Stool Specimens

1999 ◽  
Vol 37 (9) ◽  
pp. 3044-3047 ◽  
Author(s):  
Daniel P. Fedorko ◽  
Howard D. Engler ◽  
Elizabeth M. O’Shaughnessy ◽  
Esther C. Williams ◽  
Cynthia J. Reichelderfer ◽  
...  
Keyword(s):  
Predictive Value ◽  
Chart Review ◽  
Laboratory Diagnosis ◽  
Clinical Diagnostics ◽  
Becton Dickinson ◽  
Toxin A ◽  
Ofclostridium Difficile ◽  
Rapid Assays ◽  
Toxigenic Culture ◽  
Stool Specimens

Rapid laboratory diagnosis of Clostridium difficile-associated diarrhea (CDAD) is highly desirable in the setting of hospital cost containment. We tested 654 stool specimens to compare the performance of two assays for rapid detection of toxin A, the Immunocard Toxin A test (Meridian Diagnostics, Inc.) and the Culturette Brand Toxin CD enzyme immunoassay (EIA) (Becton Dickinson Microbiology Systems), with a cytotoxin assay (Cytotoxi Test; Advanced Clinical Diagnostics) and culture on cycloserine-cefoxitin-fructose agar followed by determination of the production of toxins A and B. A chart review was performed for patients whose stool specimens provided positive results on one to three of the assays. With the “gold standard” of all four assays positive or chart review evidence of CDAD, 97 (14.8%) stool specimens were positive by one or more assays and 557 (85.2%) were negative by all methods. Total agreement for all assays was 90.5% (592 of 654). The sensitivity, specificity, positive predictive value, and negative predictive value for toxigenic culture were 94.7, 98.6, 87.1, and 99.5%, respectively, for toxigenic culture; 87.7, 98.6, 86.2, and 98.8%, respectively, for the cytotoxin assay; 71.9, 99.3, 91.1, and 97.3%, respectively, for the Immunocard; and 68.4, 99.1, 88.6, and 96.9%, respectively, for the Culturette EIA. While easy to perform and highly specific, these rapid assays do not appear to be sufficient for accurate diagnosis of CDAD.

scholarly journals Evaluation of a Gastrointestinal Pathogen Panel Immunoassay in Stool Testing of Patients with Suspected Clostridioides (Clostridium) difficile Infection

2019 ◽  
Vol 57 (10) ◽  
Author(s):  
Marcela Krutova ◽  
Ales Briksi ◽  
Jan Tkadlec ◽  
Miroslav Zajac ◽  
Jana Matejkova ◽  
...  
Keyword(s):  
Clinical Symptoms ◽  
Reference Method ◽  
Gastrointestinal Infections ◽  
Toxin A ◽  
Content Type ◽  
Gastrointestinal Pathogen ◽  
Toxigenic Culture ◽  
Causative Agents ◽  
Complete Test ◽  
Stool Samples

ABSTRACT Clostridioides (Clostridium) difficile infection (CDI) is the most common causative pathogen of health care-associated gastrointestinal infections; however, due to the overlap of clinical symptoms with those of other causes of acute gastroenteritis, the selection of the most appropriate laboratory test is difficult. From April to October 2018, 640 stool samples requested for CDI testing were examined using the mariPOC CDI and Gastro test (ArcDia), which allows the detection of C. difficile glutamate dehydrogenase (GDH) and toxin A/B, norovirus genogroups GI and GII.4, rotavirus, adenovirus, and Campylobacter spp. In parallel, the C. Diff Quik Chek Complete test (Alere) was used as a routine diagnostic assay, and C. difficile toxigenic culture was used as a reference method. The sensitivity of the mariPOC CDI and Gastro test was comparable to that of C. Diff Quik Chek Complete for the detection of GDH (96.40% [95% confidence interval {CI}, 91.81% to 98.82%] versus 95.68% [95% CI, 90.84 to 98.40%]; P = 1.00) and was higher for the detection of toxin A/B (66.67% [95% CI, 57.36 to 75.11%] versus 55.56% [95% CI, 46.08 to 64.74%]; P = 0.00). The specificity of the mariPOC CDI and Gastro test was lower than that of C. Diff Quik Chek Complete for GDH detection (95.21% [95% CI, 92.96% to 96.91%] versus 97.60% [95% CI, 95.85% to 98.76%]; P = 0.04) and comparable to that of C. Diff Quik Chek Complete for toxin A/B detection (99.24 [95% CI, 98.05% to 99.79%] versus 99.81% [95% CI, 98.94% to 100.0%]; P = 0.37). In 29 cases (4.53%), other causative agents of diarrhea were detected (Campylobacter spp. [n = 17], rotavirus [n = 7], and norovirus genogroup GII.4 [n = 5]).

A Hexagonal (II) Phase Phospholipid Neutralization Assay for Lupus Anticoagulant Identification

1993 ◽  
Vol 70 (05) ◽  
pp. 787-793 ◽  
Author(s):  
Douglas A Triplett ◽  
Linda K Barna ◽  
Gail A Unger
Keyword(s):  
Hemophilia A ◽  
Clinical Laboratory ◽  
Neutralization Assay ◽  
Confirmatory Test ◽  
Specific Factor ◽  
Clinical Settings ◽  
Drug Induced ◽  
Variable Screening ◽  
Routine Clinical Laboratory

SummaryLupus anticoagulants (LAs) are immunoglobulins (IgG, IgM, or both) which interfere with in vitro phospholipid (PL) dependent tests of coagulation (e.g. APTT, dilute PT, dilute Russell Viper Venom Time). These antibodies may be identified in a wide variety of clinical settings. With the exception of heparinized patient samples, the presence of LAs is often the most common cause of an unexplained APTT in a routine clinical laboratory. The diagnosis of LAs is difficult due to variable screening reagent sensitivity and intrinsic heterogeneity of LAs. Recently, Rauch and colleagues have shown human monoclonal hybridoma LAs were inhibited by hexagonal (II) phase PLs. In contrast, lamellar phase PLs had no effect. We have evaluated a new assay system, Staclot LA®, which utilizes a hexagonal (II) phase PL (egg phosphatidylethanolamine [EPE]) as a confirmatory test for LAs. Plasma samples from the following patient populations were studied: LA positive, heparinized, oral anticoagulated, hemophilia A and B, and specific factor inhibitors (factors V, VIII, IX). Unlike previous studies, the LA positive patients were a mixed population including: autoimmune diseases, drug-induced, and post-infection. Our findings confirm the specificity of hexagonal (II) phase PL neutralization of LAs.

scholarly journals Association Between Federal Value-Based Incentive Program Implementation and Hospital-Onset C. difficile Infection Rates

2020 ◽  
Vol 41 (S1) ◽  
pp. s133-s133
Author(s):  
Mohammad Alrawashdeh ◽  
Chanu Rhee ◽  
Heather Hsu ◽  
Grace Lee
Keyword(s):  
Program Implementation ◽  
Negative Binomial ◽  
Negative Binomial Regression ◽  
Neutralization Assay ◽  
Nucleic Acid Amplification ◽  
Teaching Hospitals ◽  
Future Research ◽  
Testing Methods ◽  
Toxigenic Culture ◽  
The Impact

Background: The Hospital-Acquired Conditions Reduction Program (HACRP) and Hospital Value-Based Purchasing (HVBP) are federal value-based incentive programs that financially reward or penalize hospitals based on quality metrics. Hospital-onset C. difficile infection (HO-CDI) rates reported to the CDC NHSN became a target quality metric for both HACRP and HVBP in October 2016, but the impact of these programs on HO-CDI rates is unknown. Methods: We used an interrupted time-series design to examine the association between HACRP/HVBP implementation in October 2016 and quarterly rates of HO-CDI per 10,000 patient days among incentive-eligible acute-care hospitals conducting facility-wide HO-CDI NHSN surveillance between January 2013 and March 2019. Generalized estimating equations were used to fit negative binomial regression models to assess for immediate program impact (ie, level change) and changes in the slope of HO-CDI rates, controlling for each hospital’s predominant method for CDI testing (nucleic acid amplification including PCR (NAAT), enzyme immunoassay for toxin (EIA), or other testing method including cell cytotoxicity neutralization assay and toxigenic culture). Results: Of the 265 study hospitals studied, most were medium-sized (100–399 beds, 55%), not-for-profit (77%), teaching hospitals (70%), and were located in a metropolitan area (87%). Compared to EIA, rates of HO-CDI were higher when detected by NAAT (incidence rate ratio [IRR], 1.55; 95% CI, 1.41–1.70) or other testing methods (IRR, 1.47; 95% CI, 1.26–1.71). Controlling for CDI testing methods, HACRP/HVBP implementation was associated with an immediate 6% decline in HO-CDI rates (IRR, 0.94; 95% CI, 0.89–0.99) and a 4% decline in slope per year-quarter thereafter (IRR, 0.96; 95% CI, 0.95–0.97) (Fig. 1). Conclusions: HACRP/HVBP implementation was associated with both immediate and gradual improvements in HO-CDI rates, independent of CDI testing methods of differing sensitivity. Future research may evaluate the precise mechanisms underlying this improvement and if this impact is sustained in the long term.Funding: NoneDisclosures: None

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