scholarly journals Impact of pre-analytic step duration on molecular diagnosis of toxoplasmosis for five types of biological samples

PLoS ONE ◽  
2021 ◽  
Vol 16 (2) ◽  
pp. e0246802
Author(s):  
Marie-Pierre Brenier-Pinchart ◽  
Emmanuelle Varlet-Marie ◽  
Florence Robert-Gangneux ◽  
Denis Filisetti ◽  
Juliette Guitard ◽  
...  
Keyword(s):  
Molecular Detection ◽  
Congenital Toxoplasmosis ◽  
Buffy Coat ◽  
Clinical Samples ◽  
Sample Storage ◽  
Pcr Assay ◽  
Storage Duration ◽  
Step Duration ◽  
The Impact ◽  
Crossing Point

Introduction Toxoplasma-PCR is essential to diagnose ocular, cerebral, disseminated and congenital toxoplasmosis. This multicenter study evaluated the impact of sample storage duration at +4°C on PCR assay performances in order to propose guidelines for the storage of samples during shipment or/and before PCR. Materials and methods Five matrices, amniotic (AF), cerebrospinal (CSF), and bronchoalveolar lavage fluids (BALF), whole blood (WB) and buffy coat (BC), were artificially spiked with different amounts of Toxoplasma gondii (20, 100, 500 tachyzoites per mL of sample) or with previously infected THP1 cells. DNA extractions were performed at day 0 and after 2, 4 and 7 days of storage at +4°C. Each extract was amplified at least twice by real-time PCR. Results A total of 252 spiked samples was studied. No increase of crossing point was observed and all samples were positive for AF, BALF, BC and infected THP1-spiked WB after up to 7 days at 4°C. For CSF spiked with 20 parasites/mL, only 50% of PCR reactions were positive at D7 (p<0.05). For WB spiked with type II parasites, all reactions remained positive at D7 but amplifications were significantly delayed from D2; and for WB spiked with RH strain, the proportion of positive reactions decreased at D7. Conclusion The storage of clinical samples at +4°C is compatible with the molecular detection of T. gondii parasites. Provided that PCR assays are performed in duplicate, storage of samples is possible up to 7 days. However, from the fifth day onwards, and for samples susceptible to contain low parasitic loads, we recommend to perform the PCR in multiplicate.

scholarly journals Evaluation of Toxoplasma ELITe MGB Real-Time PCR Assay for Diagnosis of Toxoplasmosis

2017 ◽  
Vol 55 (5) ◽  
pp. 1369-1376 ◽  
Author(s):  
Florence Robert-Gangneux ◽  
Marie-Pierre Brenier-Pinchart ◽  
Hélène Yera ◽  
Sorya Belaz ◽  
Emmanuelle Varlet-Marie ◽  
...  
Keyword(s):  
Amniotic Fluid ◽  
Congenital Toxoplasmosis ◽  
Clinical Samples ◽  
Repeated Dna ◽  
Pcr Assay ◽  
Content Type ◽  
National Reference ◽  
Pcr Assays ◽  
National Reference Center ◽  
Commercial Kit

ABSTRACT Molecular diagnosis of congenital toxoplasmosis or disseminated toxoplasmosis is based mainly on PCR. The repeated DNA element rep529 has become the main DNA target used in most PCR methods, whether laboratory developed or commercial. In this multicenter study, we evaluated the Toxoplasma ELITe MGB (Elitech) commercial kit by comparison with three reference quantitative PCR assays (RAs) used routinely in three proficient laboratories of the French National Reference Center for Toxoplasmosis network, using Toxoplasma calibrated suspensions diluted to obtain a range of concentrations from 0.1 to 10,000 parasites/ml. These suspensions were extracted with either the DNA extraction kit (EXTRAblood; Elitech) recommended by the manufacturer or the QIAamp DNA minikit (Qiagen). The Toxoplasma ELITe MGB assay was also evaluated on a panel of 128 clinical samples, including 56 amniotic fluid samples, 55 placenta samples, and various other samples, of which 95 originated from patients with proven toxoplasmosis. The ELITe MGB assay amplified low-concentration replicates (<10 parasites/ml) of calibrated suspensions less frequently than the RAs of 2/3 laboratories. Additionally, the combination of EXTRAblood and Toxoplasma ELITe MGB yielded poorer sensitivity than the combination of QIAamp DNA minikit and ELITe MGB for low parasite concentrations ( P < 0.001 for 1 parasite/ml). On clinical samples, the sensitivity and the specificity of the commercial assay were 89% and 100%, respectively. The sensitivity ranged from 79% (placenta samples) to 100% (amniotic fluid samples). Overall, this study shows that the Toxoplasma ELITe MGB assay is suitable for the diagnosis of toxoplasmosis from non-cell-rich or non-hemoglobin-rich samples and that the EXTRAblood kit is not optimal.

scholarly journals Molecular Detection of Mycobacterium tuberculosis: Impact on Patient Care

2001 ◽  
Vol 47 (8) ◽  
pp. 1553-1558 ◽  
Author(s):  
Karen L Kaul
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Patient Care ◽  
Molecular Detection ◽  
Clinical Care ◽  
Antibiotic Sensitivity ◽  
Cost Of Care ◽  
Pcr Assay ◽  
Smear Negative ◽  
Pcr Assays ◽  
The Impact

Abstract Background: Nucleic acid amplification technologies such as PCR are revolutionizing the detection of infectious pathogens such as tuberculosis (TB). Amplification technology offers the potential for the diagnosis of TB in a few hours with a high degree of sensitivity and specificity. However, molecular assays neither replace nor reduce the need for conventional smear and culture, speciation, and antibiotic sensitivity assays. Methods: We undertook prospective studies of sputum samples to assess the performance of two PCR-based assays for the detection of TB as well as the impact of more rapid availability of test results on patient care. Results: The sensitivity of both the in-house and Amplicor PCR assays was 100% for smear-positive sputa. For smear-negative sputa (two sputum samples collected during the first 24 h of hospitalization), the sensitivity was 85% for our in-house PCR assay and 74% for the Roche PCR assay. Approximately 10% of the smear- and culture-negative sputa yielded positive PCR results; however, more than one-half of these were positive with both the in-house and Amplicor assays, suggesting the presence of TB DNA or organisms. Several of these came from patients whose other samples grew Mycobacterium tuberculosis during the same admission, and others came from patients who had previously treated TB. Overall, the specificities of the in-house and Amplicor PCR assays in smear-negative patients were 86% and 93%, respectively. Conclusions: Molecular detection of slow-growing pathogens such as M. tuberculosis have the potential to improve clinical care through a dramatic reduction in the time required for detection and may provide substantial savings in the overall cost of care of a patient compared with conventional smear, culture, and speciation alone, despite the fact that conventional assays must still be performed for speciation of nontuberculous mycobacteria and for full assessment of antibiotic sensitivity.

scholarly journals Diagnosis of cytomegalovirus infections by qualitative and quantitative PCR in HIV infected patients

2002 ◽  
Vol 44 (3) ◽  
pp. 127-132 ◽  
Author(s):  
Aldo de Albuquerque CUNHA ◽  
Lauro Juliano MARIN ◽  
Victor Hugo AQUINO ◽  
Luiz Tadeu Moraes FIGUEIREDO
Keyword(s):  
Quantitative Pcr ◽  
Highly Active Antiretroviral Therapy ◽  
Buffy Coat ◽  
Clinical Samples ◽  
Hiv Viral Load ◽  
Highly Active ◽  
Cd4 Lymphocyte ◽  
Cmv Disease ◽  
The Impact ◽  
Semi Quantitative Pcr

A high incidence of cytomegalovirus (CMV) infections is observed in Brazil. These viruses are causatives of significant morbidity and mortality among patients with advanced human immunodeficiency virus (HIV) infection. This work, shows the application of a PCR on determination of CMV load in the buffy coat and plasma. We analyzed the samples of 247 HIV infected patients in order to diagnose CMV infection and disease. We developed a semi-quantitative PCR that amplifies part of the glycoprotein B (gB) gene of CMV. The semi-quantitative PCR was carried out only in positive clinical samples in a qualitative PCR confirmed by a nested-PCR. CD4 lymphocyte count, HIV viral load and CMV disease symptom were correlated with CMV load. CMV genome was detected in the buffy coat of 82 of 237 (34.6%) patients, in 10 of these the CMV load was determined varying between 928 and 332 880 viral copies/mug DNA. None of these 237 patients developed any suggestive manifestation of CMV disease. For the other 10 HIV infected patients selected based on the suspicion of CMV disease, CMV genome was detected in only one case. This patient presented a high CMV load, 8 000 000 copies/mug DNA, and developed a disseminated form of CMV disease including hepatitis and retinitis. Our results were greatly influenced by the impact of the highly active antiretroviral therapy that reduced incidence of CMV viremia and occurrence of CMV disease in the HIV infected patients.

DETECTING MYCOBACTERIUM TUBERCULOSIS RAPIDLY AND MYCOBACTERIUM TUBERCULOSIS STRAINS WITHOUT IS6110 SEQUENCE BY PCR ASSAY

2012 ◽  
pp. 15-19
Author(s):  
Thi Chau Anh Nguyen ◽  
Hoang Bach Nguyen ◽  
Hai Duong Huynh ◽  
Nu Xuan Thanh Le ◽  
Xuan Cuong Le ◽  
...  
Keyword(s):  
Mycobacterium Tuberculosis ◽  
16S Rdna ◽  
False Negative ◽  
Clinical Samples ◽  
Tuberculosis Complex ◽  
Pcr Assay ◽  
Complex Objects ◽  
Method Performance ◽  
Gene Coding ◽  
16S Rdna Pcr

Background: The Nested IS6110 PCR is used for detecting tuberculosis, however IS6110 sequence is not present in the genome of all strains of M.tuberculosis, the result may be false negative. The gene coding 16S ribosome always contains a short sequence specific to M. tuberculosis complex. Objects: Performance of the 16S Real-time PCR to detect M. tuberculosis and combining to the nested IS6110 PCR to determine the rate of Mtb strains without IS6110 from clinical samples. Materials and method: Performance of 16S rDNA PCR by commercial kit of Viet A Inc. for all 480 samples, the samples which were positive with the 16S rDNA PCR were retested in IS6110 PCR assay by in-house kit. Results: The Realtime 16S rDNA PCR detected 258 cases (53.8%) of tuberculosis. There were 3 (1.2 %) M. tuberculosis strains which do not harbor IS6110 sequence in genome. Conclusion: The IS6110 nested PCR can be applied more widely than the 16S rDNA realtime PCR. In case of using IS6110 PCR assay, results may show a low proportion of false negative. Combining 16S rDNA PCR with the IS6110 based PCR allowed detection of deletion of IS6110 sequence in M. tuberculosis isolates.

scholarly journals Rapid Molecular Diagnosis of Tuberculosis and Its Resistance to Rifampicin and Isoniazid with Automated MDR/MTB ELITe MGB® Assay

Antibiotics ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 797
Author(s):  
Vichita Ok ◽  
Alexandra Aubry ◽  
Florence Morel ◽  
Isabelle Bonnet ◽  
Jérôme Robert ◽  
...  
Keyword(s):  
Drug Susceptibility ◽  
Multidrug Resistant ◽  
Drug Susceptibility Testing ◽  
Clinical Samples ◽  
Great Promise ◽  
Routine Practice ◽  
Pcr Assay ◽  
Perfect Agreement ◽  
Mdr Tb ◽  
Good Agreement

The MDR/MTB ELITe MGB® kit (ELITech) carried on the ELITe InGenius® platform is a new real-time PCR assay allowing automated extraction and detection of DNA of the Mycobacterium tuberculosis complex (MTB) and mutations in the rpoB and katG genes and inhA promoter region (pro-inhA) associated to resistance to rifampicin and isoniazid, the two markers of multidrug-resistant TB (MDR). We assessed the performances of the test on a collection of strains (n = 54) and a set of clinical samples (n = 242) from routine practice, comparatively to TB diagnosis and genotypic drug susceptibility testing (gDST) as references. Regarding the 242 clinical samples, the sensitivity and specificity of MTB detection by ELITe were 90.9% and 97.5%, respectively. For the detection of resistance-conferring mutations on positive clinical samples, we observed perfect agreement with gDST for katG and pro-inhA (κ = 1.0) and two discordant results for rpoB (κ = 0.82). Considering the 54 cultured strains, very good agreement with gDST was observed for the detection of the 25 distinct mutations in rpoB, katG, and pro-inhA, (κ = 0.95, 0.88, and 0.95, respectively). In conclusion, the automated MDR/MTB ELITe MGB® assay shows great promise and appears to be a valuable tool for rapid detection of pre-MDR- and MDR-TB directly from clinical specimens.

scholarly journals Analysis and validation of a highly sensitive one-step nested quantitative real-time polymerase chain reaction assay for specific detection of severe acute respiratory syndrome coronavirus 2

2020 ◽  
Vol 17 (1) ◽  
Author(s):  
Yang Zhang ◽  
Chunyang Dai ◽  
Huiyan Wang ◽  
Yong Gao ◽  
Tuantuan Li ◽  
...  
Keyword(s):  
Polymerase Chain Reaction ◽  
Real Time ◽  
Quantitative Polymerase Chain Reaction ◽  
Clinical Samples ◽  
Chain Reaction ◽  
Pcr Assay ◽  
Qrt Pcr ◽  
Highly Sensitive ◽  
One Step ◽  
Polymerase Chain

Abstract Background Coronavirus disease 2019 (COVID-19), caused by SARS-CoV-2, is posing a serious threat to global public health. Reverse transcriptase real-time quantitative polymerase chain reaction (qRT-PCR) is widely used as the gold standard for clinical detection of SARS-CoV-2. Due to technical limitations, the reported positive rates of qRT-PCR assay of throat swab samples vary from 30 to 60%. Therefore, the evaluation of alternative strategies to overcome the limitations of qRT-PCR is required. A previous study reported that one-step nested (OSN)-qRT-PCR revealed better suitability for detecting SARS-CoV-2. However, information on the analytical performance of OSN-qRT-PCR is insufficient. Method In this study, we aimed to analyze OSN-qRT-PCR by comparing it with droplet digital PCR (ddPCR) and qRT-PCR by using a dilution series of SARS-CoV-2 pseudoviral RNA and a quality assessment panel. The clinical performance of OSN-qRT-PCR was also validated and compared with ddPCR and qRT-PCR using specimens from COVID-19 patients. Result The limit of detection (copies/ml) of qRT-PCR, ddPCR, and OSN-qRT-PCR were 520.1 (95% CI: 363.23–1145.69) for ORF1ab and 528.1 (95% CI: 347.7–1248.7) for N, 401.8 (95% CI: 284.8–938.3) for ORF1ab and 336.8 (95% CI: 244.6–792.5) for N, and 194.74 (95% CI: 139.7–430.9) for ORF1ab and 189.1 (95% CI: 130.9–433.9) for N, respectively. Of the 34 clinical samples from COVID-19 patients, the positive rates of OSN-qRT-PCR, ddPCR, and qRT-PCR were 82.35% (28/34), 67.65% (23/34), and 58.82% (20/34), respectively. Conclusion In conclusion, the highly sensitive and specific OSN-qRT-PCR assay is superior to ddPCR and qRT-PCR assays, showing great potential as a technique for detection of SARS-CoV-2 in patients with low viral loads.

Effect of initial moisture content and sample storage duration on compost stability using the ORG0020 dynamic respiration test

2021 ◽  
Vol 125 ◽  
pp. 215-219 ◽  
Author(s):  
Nisha N. Gurusamy ◽  
Natalie Puffer ◽  
Coen de Jongh ◽  
Cristina Rodriguez Gil ◽  
Thomas J. Aspray
Keyword(s):  
Moisture Content ◽  
Initial Moisture Content ◽  
Sample Storage ◽  
Storage Duration ◽  
Compost Stability

scholarly journals Evaluation of the New BD Max GC Real-Time PCR Assay, Analytically and Clinically as a Supplementary Test for the BD ProbeTec GC Qx Amplified DNA Assay, for Molecular Detection of Neisseria gonorrhoeae

2015 ◽  
Vol 53 (12) ◽  
pp. 3935-3937 ◽  
Author(s):  
Daniel Golparian ◽  
Stina Boräng ◽  
Martin Sundqvist ◽  
Magnus Unemo
Keyword(s):  
Neisseria Gonorrhoeae ◽  
Real Time ◽  
Sensitivity And Specificity ◽  
Real Time Pcr ◽  
Molecular Detection ◽  
Analytical Sensitivity ◽  
Pcr Assay ◽  
Content Type ◽  
Dna Assay ◽  
Supplementary Test

The new BD Max GC real-time PCR assay showed high clinical and analytical sensitivity and specificity. It can be an effective and accurate supplementary test for the BD ProbeTec GC Qx amplified DNA assay, which had suboptimal specificity, and might also be used for initial detection ofNeisseria gonorrhoeae.

The Effects of Storage Duration on Biodiesel Derived from Waste Cooking Oil

2014 ◽  
Vol 660 ◽  
pp. 386-390 ◽  
Author(s):  
Norazwan Azman ◽  
Mirnah Suardi ◽  
Amir Khalid
Keyword(s):  
Diesel Fuel ◽  
Fossil Fuels ◽  
Acid Value ◽  
Waste Cooking Oil ◽  
Biodiesel Fuel ◽  
Storage Duration ◽  
Fuel Prices ◽  
Cooking Oil ◽  
Impact Reduction ◽  
The Impact

The use of fossil fuels as energy sources has grown to significantly be likely to have a major environmental impact. Reduction of world oil reserves and increasing environmental concerns have prompted alternative is found and renewable source of energy called biodiesel. Biodiesel fuel from vegetable oil is considered as the best candidates for diesel fuel replacement in diesel engines because of its closer. Fuel prices are going up day by day in the world. Thus, the means and methods have been trying for years to get fuel alternative outcomes. This study investigated the effects of different storage periods used in quality biodiesel blends (B5, B10, B15) of waste cooking oil and diesel fuel under low temperature and the temperature of the environment. Biodiesel samples were stored in glass containers under indoor conditions, and outdoor conditions for 10 weeks in total. These samples were monitored on a weekly basis through the test properties. The experimental density, viscosity, acid value, water content and flash point discussed in detail. Biodiesel storage at low temperatures is suitable and more advantageous because the impact on the physical properties is minimal and beneficial to slow down the degradation of biodiesel and storage.

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