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 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 Toxin Detection by Cell Culture Neutralization Assay [CYT] and Toxin based EIA [Tox EIA] among Recurrent Episodes of CDI Diagnosed by PCR

2017 ◽  
Vol 4 (suppl_1) ◽  
pp. S395-S395
Author(s):  
Mini Kamboj ◽  
Tracy Mcmillen ◽  
Hoi Yan Chow ◽  
Jennifer Brite ◽  
N Esther Babady
Keyword(s):  
Gold Standard ◽  
Diagnostic Tests ◽  
Ad Hoc ◽  
Index Case ◽  
Extended Period ◽  
High Sensitivity ◽  
Neutralization Assay ◽  
Significant Implication ◽  
Stool Samples ◽  
Positive Recurrent

Abstract Background The Ad Hoc C. difficile surveillance working group defines recurrent C. difficile infection as a second episode occurring >8 weeks after the index case. Due to its high sensitivity, diagnosis of recurrent CDI by PCR is extremely challenging in patients who may have persistent, PCR detectable shedding of toxigenic C. difficile (TCD) for an extended period of time after treatment of the initial CDI episode. CYT, which detects C. difficile toxin antigen, is a cumbersome test to perform but is considered as the current clinical diagnostic gold standard for CDI diagnosis. Aim: To determine the CYT and Toxin A/B EIA positivity among patients with recurrent CDI episodes detected by PCR. We further characterized the performance of diagnostic tests based on whether the recurrent episode was a relapse or reinfection. Methods During a three month study period, CYT and Tox A/B EIA was performed on consecutive stool samples submitted from PCR positive recurrent episodes of CDI. For the purpose of this study, recurrence was defined as a second episode of CDI that occurred within 120 days from the most recent episode. MLST analysis was performed as previously described to characterize relapse and reinfection among the recurrent episodes (2). Results Thirty-five recurrent episodes occurred over the study period. 21/35 [60%] were positive by CYT and 12/35 [34%] by Tox A/B EIA. Among the recurrent CDI episodes, 16 (46%) were genotypical confirmed as relapse with the original infecting strain. Majority of these relapses were positive by CYT (81%) when compared with Tox EIA (43%). Among patients with geno typically confirmed reinfection (n = 8), CYT and EIA positivity was 63 % and 50 % respectively. For the remaining 11 episodes, TCD was not retrievable in culture, CYT and EIA positivity among this group was 27 % and 9 % respectively. Conclusion Forty percent of recurrent CDI episodes detected by PCR could not be confirmed by CYT. EIA missed 66 % of CYT positive recurrent CDI. The performance of CYT and EIA varied among recurrences due to relapse and reinfection. These results have significant implication for reporting of CDI HAI rates. Disclosures All authors: No reported disclosures.

scholarly journals Evaluation of CAMPYLOBACTER QUIK CHEK™ rapid membrane enzyme immunoassay to detect Campylobacter spp. antigen in stool samples

Gut Pathogens ◽  
2021 ◽  
Vol 13 (1) ◽  
Author(s):  
Justine Franco ◽  
Lucie Bénejat ◽  
Astrid Ducournau ◽  
Francis Mégraud ◽  
Philippe Lehours ◽  
...  
Keyword(s):  
Screening Method ◽  
Positive Culture ◽  
National Reference ◽  
Negative Culture ◽  
Membrane Enzyme ◽  
Adults And Children ◽  
Stool Samples ◽  
National Reference Center ◽  
Campylobacter Spp ◽  
Composite Reference Standard

AbstractCampylobacter spp. enteritis is the most frequent bacterial enteritis in both adults and children and is sometimes a source of severe complications. Its diagnosis by culture suffers from a lack of sensitivity and delays the result, preventing an early initiation of optimal antibiotic therapy in some cases. Our aim was to test a new rapid immuno-enzymatic method for Campylobacter spp. diagnosis in comparison to a composite reference standard (CRS). Stool samples from the French National Reference Center for Campylobacter and Helicobacter were tested with the CAMPYLOBACTER QUIK CHEK™ (Abbott). The CRS used to consider a case positive for Campylobacter spp. was a positive culture and, in case of a negative culture, a positive result obtained with both an ELISA and a molecular test. One hundred and eight stools were included: 53 were positive according to the CRS. If performed alone, culture would have missed 5 cases which the CAMPYLOBACTER QUIK CHEK™ detected. Finally, the CAMPYLOBACTER QUIK CHEK™ showed a sensitivity of 96.2% and a specificity of 94.5% and is relevant for clinical practice. Given the characteristics of the new method, it can be used as a screening method for Campylobacter spp. detection.

The Peguero-Lo Presti criteria has the highest diagnostic accuracy for the diagnosis of left ventricular hypertrophy in the elderly

2020 ◽  
Vol 41 (Supplement_2) ◽  
Author(s):  
C.A.M Tavares ◽  
N Samesima ◽  
L.A Hajjar ◽  
L.C Godoy ◽  
E.M.P Hirano ◽  
...  
Keyword(s):  
Left Ventricular Hypertrophy ◽  
Diagnostic Accuracy ◽  
Ventricular Hypertrophy ◽  
The Elderly ◽  
Left Ventricular ◽  
Accuracy Score ◽  
Increased Sensitivity ◽  
Low Sensitivity ◽  
Ecg Criteria ◽  
Improved Accuracy

Abstract Background Left Ventricular Hypertrophy (LVH) is an independent predictor of mortality and cardiovascular morbidity and the 12-lead ECG is recommended as a universal screening for patients with hypertension. However, the ECG has low sensitivity and there is limited data in patients 70 years or older. The recently published Peguero-Lo Presti (PLP) criteria had improved accuracy compared with other ECG criteria but with very few patients with age ≥70 years included. Purpose To compare the accuracy of the PLP criteria versus the traditional ECG criteria for detecting LVH in patients ≥70 years. Methods Retrospective single-center study. Patients were included if they were 70 years or older and underwent an ECG and echocardiogram (gold standard) less than 180 days apart from jan/2017 to mar/2018. Patients with left or right bundle branch block, non-sinus rhythm or ventricular paced rhythm were excluded. All tracings were independently reviewed by two cardiologists, blinded to the echocardiogram. The PLP criteria was compared against Cornell voltage (CV), Sokolow-Lyon voltage (SL), and Romhilt-Estes 4 and 5 (RE) criteria. LVH was defined as a left ventricular mass index >115 g/m2 in males and >95 g/m2 in females, according to the echocardiogram. McNemar's test, F1 score, and the area under the Receiver Operating Characteristic curves (AUC) were used to compare the diagnostic performance of the tests Results A total of 592 patients were included (mean age 77.5 years, SD: 5.9; 50.8% were women). The PLP criteria had increased sensitivity compared with both the SL and CV criteria (p<0.0001 for both comparisons) and RE5 (p=0.042). PLP also had better specificity than the RE4 criteria (p<0.0001) and the highest F1 accuracy score (Table 1). The AUC of the PLP was significantly higher than the AUC of the CV and RE criteria (0.70 vs 0.66 vs 0.64, respectively, p<0.05) and numerically higher than the SL criteria (AUC=0.67, p=0.311, Figure 1). Conclusion Compared to the traditional ECG criteria for LVH, the PLP criteria had the highest diagnostic accuracy in elderly patients. Figure 1. AUC of the ECG criteira Funding Acknowledgement Type of funding source: None

scholarly journals Second harmonic generation correlation spectroscopy for characterizing translationally diffusing protein nanocrystals

2016 ◽  
Vol 72 (7) ◽  
pp. 849-859
Author(s):  
Ximeng Y. Dow ◽  
Christopher M. Dettmar ◽  
Emma L. DeWalt ◽  
Justin A. Newman ◽  
Alexander R. Dow ◽  
...  
Keyword(s):  
Second Harmonic Generation ◽  
Harmonic Generation ◽  
Unit Volume ◽  
Second Harmonic ◽  
Incident Beam ◽  
High Sensitivity ◽  
Correlation Spectroscopy ◽  
Optical Process ◽  
Active Nanoparticles ◽  
Low Sensitivity

Second harmonic generation correlation spectroscopy (SHG-CS) is demonstrated as a new approach to protein nanocrystal characterization. A novel line-scanning approach was performed to enable autocorrelation analysis without sample damage from the intense incident beam. An analytical model for autocorrelation was developed, which includes a correction for the optical scattering forces arising when focusing intense, infrared beams. SHG-CS was applied to the analysis of BaTiO3nanoparticles ranging from 200 to ∼500 nm and of photosystem I nanocrystals. A size distribution was recovered for each sample and compared with the size histogram measured by scanning electron microscopy (SEM). Good agreement was observed between the two independent measurements. The intrinsic selectivity of the second-order nonlinear optical process provides SHG-CS with the ability to distinguish well ordered nanocrystals from conglomerates and amorphous aggregates. Combining the recovered distribution of particle diameters with the histogram of measured SHG intensities provides the inherent hyperpolarizability per unit volume of the SHG-active nanoparticles. Simulations suggest that the SHG activity per unit volume is likely to exhibit relatively low sensitivity to the subtle distortions within the lattice that contribute to resolution loss in X-ray diffraction, but high sensitivity to the presence of multi-domain crystals.

Remote, Long-Pathlength Cell for High-Sensitivity Raman Spectroscopy

1987 ◽  
Vol 41 (1) ◽  
pp. 126-130 ◽  
Author(s):  
Scott D. Schwab ◽  
Richard L. McCreery
Keyword(s):  
Fiber Optics ◽  
Laser Light ◽  
Capillary Tube ◽  
High Sensitivity ◽  
Sample Tube ◽  
Increased Sensitivity ◽  
Sampling Systems ◽  
Power Densities ◽  
Objective Being ◽  
Focused Beam

Fiber optics were used to interface a Raman spectrometer to a long (1 m) sample tube, with the objective being increased sensitivity. Internal reflection of the laser light and the Raman scatter within the sample tube permitted a long solution length to be sampled, increasing the Raman sensitivity by factors of 30–50 over conventional capillary tube sampling systems. In addition, the sample was subjected to much lower power densities than with systems employing a focused beam, thus minimizing radiation damage. Detection limits of 10−9 to 10−8 M were achieved for resonance Raman scatterers, and normal Raman scatterers could be detected at the 1 × 10−5 M level.

scholarly journals 781. C.difficile PCR+/ Toxin EIA- treat or not treat? A clinician survey

2020 ◽  
Vol 7 (Supplement_1) ◽  
pp. S435-S436
Author(s):  
Sarath G Nath ◽  
Francesca Lee ◽  
Anjali Bararia ◽  
Ank E Nijhawan
Keyword(s):  
Clinical Judgment ◽  
Clinical Care ◽  
Cost Effective ◽  
False Positive Diagnosis ◽  
Missed Diagnosis ◽  
Stool Samples ◽  
Polymerase Chain ◽  
Low Sensitivity ◽  
Survey Responses ◽  
And Training

Abstract Background C.difficile Toxin Polymerase Chain Reaction (C.diff PCR) and C.difficile Toxin Enzyme Immunoassays (toxin EIA) are commonly used tests to diagnose Clostridoides difficile infection (CDI). C.diff PCR cannot differentiate between colonization and infection, leading to a higher false-positive diagnosis of CDI. Toxin EIA has low sensitivity leading to a missed diagnosis of CDI. In patients with C.diff PCR positive(+) and Toxin EIA negative(-), clinical judgment is often needed regarding the decision to treat or not to treat. C.diff cytotoxic assay (CCA), is a more sensitive method to detect the toxin but is time-consuming and not readily available. Methods Between 6/2019 and 12/2019, 83 patients who were admitted to the hospital, met our inclusion criteria (C.diff PCR+/EIA-). Clinicians who cared for these patients were contacted and surveyed with a predesigned questionnaire evaluating the rationale of treatment. Also, a simultaneous medical records review was done to ensure consistency. Along with this C.diff PCR+/EIA- stool samples were sent to ARUP laboratories for CCA. The CCA results were not available for clinicians and did not impact clinical care. Average cost for a CCA assay was $29 Results Demographics of the clinicians were variable (Table 1). Several parameters were considered when making decisions regarding treatment and GI/ID were frequently involved (figure 1). Among the 83 patients, 41(49%) were CCA (+) and 42(51%) were CCA (-). 48 of 83 (58%) patients received treatment for CDI. 25 of 48 (52%) patients who were treated were CCA positive while 23 of 48 (48%) patients were CCA negative. Among the untreated patients, 16/35 (46%) were CCA+ while 19/35(54%) were CCA-. There was no statistically significant correlation between clinical judgment and CCA assay results (p: 0.56 on the Chi test). Demographics of the clinicians Clinician survey responses CDI Treatment and by CCA positivity Conclusion Clinicians regardless of their background and training face challenges with the treatment of C.diff PCR+/EIA- patients. Patient outcomes based on the incorporation of CCA assay into an algorithm for C.diff PCR+/EIA- patients, need to be evaluated. But it has a potential role in stopping unnecessary CDI treatment as well as avoidance of missed treatment opportunities while possibly also being cost-effective. Disclosures Ank E. Nijhawan, MD, MPH, Gilead (Grant/Research Support, Scientific Research Study Investigator, Research Grant or Support)

Influence of Irrational Beliefs and Sensitivity to a Person on Future Psychology Students’ Propensity to Coercion or Nonviolence

2021 ◽  
pp. 143-165
Author(s):  
V.G. Maralov ◽  
◽  
V.A. Sitarov ◽  
Keyword(s):  
Irrational Beliefs ◽  
High Sensitivity ◽  
Daily Practice ◽  
Psychology Students ◽  
State Universities ◽  
Low Level ◽  
Level Of Understanding ◽  
Low Sensitivity ◽  
High Level ◽  
Dependent Type

The relevance of the problem is due to the importance of identifying factors that determine the propensity of students to coercion or nonviolence, creating psychological and pedagogical conditions for the formation of the socionomic sphere of nonviolent competencies for future specialists at universities. The theoretical basis of the study was the position of nonviolence as a daily practice of interaction, by which we understand the ability of a person to choose from a number of possible alternatives that carry the least charge of coercion. The aim of the work was to study the influence of irrational beliefs and sensitivity to a person (interest, empathy, understanding and assistance) on the students’ tendency to coercion, manipulation, non-violence and non-interference in the processes of interaction with people. The hypothesis was tested that the tendency of students to coercion, manipulation, and noninterference will be due to expressed irrational beliefs and low level of sensitivity to a person and the tendency to non-violence will be explained by the absence of irrational beliefs and a high level of sensitivity to a person. The study involved 125 students of pedagogical and psychological faculties of the Moscow Humanitarian and Cherepovets State universities. The authors used questionnaires to identify the positions of interaction among students and sensitivity to a person, as well as a list of irrational beliefs proposed by A. Beck and A. Freeman. It is established that the tendency to both coercion and manipulation are determined by the beliefs of anti-social type and low sensitivity to the person. The tendency to manipulate the narcissistic beliefs, high interest in people and understanding them, at the same time the tendency to non-violence and non-interference are determined by beliefs of avoidant and dependent types with a low level of understanding people. And a tendency to non-interference is determined by beliefs of dependent type with unexpressed orientation on helping. The tendency to nonviolence is determined by the high sensitivity to a person and the absence of irrational beliefs of antisocial, passive-aggressive and narcissistic types. As a result, the conclusion is made about the need to form purposefully the ability to nonviolent interaction among students, which should include the work on awareness and overcoming irrational beliefs and the development of sensitivity to a person. The obtained results can be used in practical work with students on the formation of their nonviolent competencies.

Prevalence of Chlamydia Trachomatis Infections in Symptomatic Patients in Bulgaria

2005 ◽  
Vol 3 (2) ◽  
pp. 83-87
Author(s):  
V. Ouzounova ◽  
J. Haralambieva ◽  
I. Mitov
Keyword(s):  
Monoclonal Antibody ◽  
Chlamydial Infection ◽  
High Sensitivity ◽  
Culture Method ◽  
Sexual Partners ◽  
Lower Prevalence ◽  
Active Infection ◽  
High Prevalence ◽  
Reiter Syndrome ◽  
Made In

The aim of the study was to investigate the prevalence of C. trachomatis infection in symptomatic patients and to compare our data with similar studies made in Bulgaria. 822 patients were included in the study with a diagnosis suggestive of Chlamydial infection: urethritis, prostatitis, Reiter syndrome, cervicitis, salpingitis, pelvic inflammatory disease, ectopic pregnancy, infertility, etc. The samples were cell cultured on McCoy and detected by immunofluorescence with anti-lipopolysaccharide monoclonal antibody. The prevalence of C. trachomatis infection in symptomatic patients was about 37% in the investigated 822 urogenital samples (568 women and 254 men). Active infection with C. trachomatis was detected in 39% of the women and in 33% of the men. Our study shows a relatively high prevalence of C. trachomatis infection in symptomatic patients; a lower prevalence of the infection in comparison with other Bulgarian studies, using different methods for detection. The results prove the high sensitivity and specificity of the cell-culture method for the detection of Chlamydial infections and the need for screening of the symptomatic patients and their sexual partners for Chlamydial infection.

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