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 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 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]).

scholarly journals Comparison of the Superpolymyxin and ChromID Colistin R Screening Media for the Detection of Colistin-Resistant Enterobacteriaceae from Spiked Rectal Swabs

2018 ◽  
Vol 63 (1) ◽  
Author(s):  
Delphine Girlich ◽  
Thierry Naas ◽  
Laurent Dortet
Keyword(s):  
Escherichia Coli ◽  
Klebsiella Pneumoniae ◽  
Confidence Interval ◽  
Enterobacter Cloacae ◽  
Bacterial Isolates ◽  
Colistin Resistance ◽  
Gram Negative ◽  
Content Type ◽  
Rectal Swabs ◽  
Stool Samples

ABSTRACT The dissemination of carbapenemase-producing Enterobacteriaceae (CPE) has led to the increased use of colistin, which has resulted in the emergence of colistin-resistant Enterobacteriaceae worldwide. One of the most threatening scenarios is the dissemination of colistin resistance in CPE, particularly the plasmid-encoded resistance element MCR. Thus, it has now become mandatory to possess reliable media to screen for colistin-resistant Gram-negative bacterial isolates, especially Enterobacteriaceae. In this study, we evaluated the performances of the Superpolymyxin medium (ELITechGroup) and the ChromID Colistin R medium (bioMérieux) to screen for colistin-resistant Enterobacteriaceae from spiked rectal swabs. Stool samples were spiked with a total of 94 enterobacterial isolates (Escherichia coli, Klebsiella pneumoniae, Salmonella enterica, Enterobacter cloacae), including 53 colistin-resistant isolates. ESwabs (Copan Diagnostics) were then inoculated with those spiked fecal suspensions, and culture proceeded as recommended by both manufacturers. The sensitivity of detection of colistin-resistant Enterobacteriaceae was 86.8% (95% confidence interval [95% CI] = 74.0% to 94.0%) using both the Superpolymyxin medium and the ChromID Colistin R plates. Surprisingly, the isolates that were not detected were not the same for both media. The specificities were high for both media, at 97.9% (95% CI = 87.3% to 99.9%) for the Superpolymyxin medium and 100% (95% CI = 90.4% to 100%) for the ChromID Colistin R medium. Both commercially available media, ChromID Colistin R and Superpolymyxin, provide useful tools to screen for colistin-resistant Enterobacteriaceae from patient samples (rectal swabs) regardless of the level and mechanism of colistin resistance.

scholarly journals Description of Citrobacter cronae sp. nov., isolated from human rectal swabs and stool samples

2020 ◽  
Vol 70 (5) ◽  
pp. 2998-3003 ◽  
Author(s):  
Philipp Oberhettinger ◽  
Leonard Schüle ◽  
Matthias Marschal ◽  
Daniela Bezdan ◽  
Stephan Ossowski ◽  
...  
Keyword(s):  
New Species ◽  
University Hospital ◽  
Whole Genome Sequencing Data ◽  
Rrna Gene ◽  
Content Type ◽  
Link Type ◽  
Separate Branch ◽  
Rectal Swabs ◽  
Stool Samples ◽  
Type Strains

Nine independent Gram-negative bacterial strains were isolated from rectal swabs or stool samples of immunocompromised patients from two different wards of a university hospital. All isolates were phylogenetically analysed based on their 16S rRNA gene sequence, housekeeping gene recN, multilocus sequence analysis of concatenated partial fusA, leuS, pyrG and rpoB sequences, and by whole genome sequencing data. The analysed strains of the new species cluster together and form a separate branch with Citrobacter werkmanii NBRC105721T as the most closely related species. An average nucleotide identity value of 95.9–96% and computation of digital DNA–DNA hybridization values separate the new species from all other type strains of the genus Citrobacter . Biochemical characteristics further delimit the isolates from closely related Citrobacter type strains. As a result of the described data, a new Citrobacter species is introduced, for which the name Citrobacter cronae sp. nov. is proposed. The type strain is Tue2-1T with a G+C DNA content of 52.2 mol%.

scholarly journals Sensitivity of Single-Molecule Array Assays for Detection of Clostridium difficile Toxins in Comparison to Conventional Laboratory Testing Algorithms

2018 ◽  
Vol 56 (8) ◽  
Author(s):  
Alice Banz ◽  
Aude Lantz ◽  
Brigitte Riou ◽  
Agnès Foussadier ◽  
Mark Miller ◽  
...  
Keyword(s):  
Clostridium Difficile ◽  
Single Molecule ◽  
Laboratory Diagnosis ◽  
Case Definition ◽  
Cell Cytotoxicity ◽  
Toxin A ◽  
Toxin B ◽  
Content Type ◽  
High Performing ◽  
Molecular Tests

ABSTRACT Guidelines recommend the use of an algorithm for the laboratory diagnosis of Clostridium difficile infection (CDI). Enzyme immunoassays (EIAs) detecting C. difficile toxins cannot be used as standalone tests due to suboptimal sensitivity, and molecular tests suffer from nonspecificity by detecting colonization. Sensitive immunoassays have recently been developed to improve and simplify CDI diagnosis. Assays detecting CD toxins have been developed using single-molecule array (SIMOA) technology. SIMOA performance was assessed relative to a laboratory case definition of CDI defined by positive glutamate dehydrogenase (GDH) screen and cell cytotoxicity neutralizing assay (CCNA). Samples were tested with SIMOA assays and a commercial toxin EIA to compare performance, with discrepancy resolution using a commercial nucleic acid-based test and a second cell cytotoxicity assay. The SIMOA toxin A and toxin B assays showed limits of detection of 0.6 and 2.9 pg/ml, respectively, and intra-assay coefficients of variation of less than 10%. The optimal clinical thresholds for the toxin A and toxin B assays were determined to be 22.1 and 18.8 pg/ml, respectively, with resultant sensitivities of 84.8 and 95.5%. In contrast, a high-performing EIA toxin test had a sensitivity of 71.2%. Thus, the SIMOA assays detected toxins in 24% more samples with laboratory-defined CDI than the high performing toxin EIA (95% [63/66] versus 71% [47/66]). This study shows that SIMOA C. difficile toxin assays have a higher sensitivity than currently available toxin EIA and have the potential to improve CDI diagnosis.

scholarly journals Detection of Clostridium difficile in Feces of Asymptomatic Patients Admitted to the Hospital

2016 ◽  
Vol 55 (2) ◽  
pp. 403-411 ◽  
Author(s):  
Elisabeth M. Terveer ◽  
Monique J. T. Crobach ◽  
Ingrid M. J. G. Sanders ◽  
Margreet C. Vos ◽  
Cees M. Verduin ◽  
...  
Keyword(s):  
Clostridium Difficile ◽  
Predictive Value ◽  
Health Care Facilities ◽  
Nucleic Acid Amplification ◽  
Content Type ◽  
Asymptomatic Patients ◽  
Toxigenic Culture ◽  
Stool Samples ◽  
Sensitivity Specificity ◽  
Low Prevalence

ABSTRACTRecent evidence shows that patients asymptomatically colonized withClostridium difficilemay contribute to the transmission ofC. difficilein health care facilities. Additionally, these patients may have a higher risk of developingC. difficileinfection. The aim of this study was to compare a commercially available PCR directed to both toxin A and B (artusC. difficileQS-RGQ kit CE; Qiagen), an enzyme-linked fluorescent assay to glutamate dehydrogenase (GDH ELFA) (Vidas, bioMérieux), and an in-house-developed PCR totcdB, with (toxigenic) culture ofC. difficileas the gold standard to detect asymptomatic colonization. Test performances were evaluated in a collection of 765 stool samples obtained from asymptomatic patients at admission to the hospital. TheC. difficileprevalence in this collection was 5.1%, and 3.1% contained toxigenicC. difficile. Compared toC. difficileculture, the sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of theC. difficileGDH ELFA were 87.2%, 91.2%, 34.7%, and 99.3%, respectively. Compared with results of toxigenic culture, the sensitivity, specificity, PPV, and NPV of the commercially available PCR and the in-house PCR were 95.8%, 93.4%, 31.9%, 99.9%, and 87.5%, 98.8%, 70%, and 99.6%, respectively. We conclude that in a low-prevalence setting of asymptomatically colonized patients, both GDH ELFA and a nucleic acid amplification test can be applied as a first screening test, as they both display a high NPV. However, the low PPV of the tests hinders the use of these assays as stand-alone tests.

scholarly journals Evaluating the Effects of Surotomycin Treatment on Clostridium difficile Toxin A and B Production, Immune Response, and Morphological Changes

2016 ◽  
Vol 60 (6) ◽  
pp. 3519-3523 ◽  
Author(s):  
Bradley T. Endres ◽  
Eugénie Bassères ◽  
Mohammed Khaleduzzaman ◽  
M. Jahangir Alam ◽  
Laurent Chesnel ◽  
...  
Keyword(s):  
Immune Response ◽  
Clostridium Difficile ◽  
Morphological Changes ◽  
Toxin Production ◽  
Morphological Data ◽  
Growth Media ◽  
Toxin A ◽  
Content Type ◽  
Cyclic Lipopeptide ◽  
The Impact

Surotomycin is a cyclic lipopeptide in development forClostridium difficile-associated diarrhea. This study aimed to assess the impact of surotomycin exposure onC. difficiletoxin A and B concentrations and the associated changes in immune response in comparison to vancomycin and metronidazole. Time-kill curve assays were performed using strain R20291 (BI/NAP1/027) at supra-MICs (4× and 40×) and sub-MICs (0.5×) of surotomycin and comparators. Following treatment, CFU counts, toxin A and B concentrations, and cellular morphological changes using scanning electron microscopy were examined. Inflammatory response was determined by measuring interleukin-8 (IL-8) concentrations from polarized Caco-2 cells exposed to antibiotic-treatedC. difficilegrowth media. Supra-MICs (4× and 40×) of surotomycin resulted in a reduction of vegetative cells over 72 h (4-log difference,P< 0.01) compared to controls. These results correlated with decreases of 77% and 68% in toxin A and B production at 48 h, respectively (P< 0.005, each), which resulted in a significant reduction in IL-8 concentration compared to controls. Similar results were observed with comparator antibiotics. Bacterial cell morphology showed that the cell wall was broken apart by surotomycin treatment at supra-MICs while sub-MIC studies showed a “deflated” phenotype plus a rippling effect. These results suggest that surotomycin has potent killing effects onC. difficilethat results in reduced toxin production and attenuates the immune response similar to comparator antibiotics. The morphological data also confirm observations that surotomycin is a membrane-active antibiotic.

scholarly journals Use of an Enrichment Broth Improves Detection of Extended-Spectrum-Beta-Lactamase-Producing Enterobacteriaceae in Clinical Stool Samples

2015 ◽  
Vol 54 (2) ◽  
pp. 467-470 ◽  
Author(s):  
Nathalie Jazmati ◽  
Rebecca Hein ◽  
Axel Hamprecht
Keyword(s):  
Beta Lactamase ◽  
Enrichment Broth ◽  
Content Type ◽  
Extended Spectrum Beta Lactamase ◽  
Extended Spectrum ◽  
Stool Samples ◽  
The Impact ◽  
Diagnostic Step

This study evaluated the impact of preenrichment on the detection of extended-spectrum beta-lactamase-producingEnterobacteriaceae(ESBL-E) in clinical stool samples. ESBL-E were detected in 41 of 343 patients (12.0%). As 31.7% of the ESBL-E carriers were identified by preenrichment, only this additional diagnostic step significantly improved the detection of ESBL-E.

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 the cobas Cdiff Test for Detection of Toxigenic Clostridium difficile in Stool Samples

2017 ◽  
Vol 55 (12) ◽  
pp. 3426-3436 ◽  
Author(s):  
Lance R. Peterson ◽  
Stephen A. Young ◽  
Thomas E. Davis ◽  
Zi-Xuam Wang ◽  
John Duncan ◽  
...  
Keyword(s):  
Clostridium Difficile ◽  
False Negative ◽  
Reference Method ◽  
Culture Method ◽  
Nucleic Acid Amplification ◽  
Culture Methods ◽  
Content Type ◽  
Toxigenic Culture ◽  
Discrepancy Analysis ◽  
Stool Samples

ABSTRACTNucleic acid amplification tests (NAATs) are reliable tools for the detection of toxigenicClostridium difficilefrom unformed (liquid or soft) stool samples. The objective of this study was to evaluate performance of the cobas Cdiff test on the cobas 4800 system using prospectively collected stool specimens from patients suspected of havingC. difficileinfection (CDI). The performance of the cobas Cdiff test was compared to the results of combined direct and broth-enriched toxigenic culture methods in a large, multicenter clinical trial. Additional discrepancy analysis was performed by using the XpertC. difficileEpi test. Sample storage was evaluated by using contrived and fresh samples before and after storage at −20°C. Testing was performed on samples from 683 subjects (306 males and 377 females); 113 (16.5%) of 683 subjects were positive for toxigenicC. difficileby direct toxigenic culture, and 141 of 682 subjects were positive by using the combined direct and enriched toxigenic culture method (reference method), for a prevalence rate of 20.7%. The sensitivity and specificity of the cobas Cdiff test compared to the combined direct and enriched culture method were 92.9% (131/141; 95% confidence interval [CI], 87.4% to 96.1%) and 98.7% (534/541; 95% CI, 97.4% to 99.4%), respectively. Discrepancy analysis using results for retested samples from a second NAAT (Xpert C. difficile/Epi test; Cepheid, Sunnyvale, CA) found no false-negative and 4 false-positive cobas Cdiff test results. There was no difference in positive and negative results in comparisons of fresh and stored samples. These results support the use of the cobas Cdiff test as a robust aid in the diagnosis of CDI.

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