scholarly journals Analytical Performances of Human Immunodeficiency Virus Type 1 RNA-Based Amplix® Real-Time PCR Platform for HIV-1 RNA Quantification

2016 ◽  
Vol 2016 ◽  
pp. 1-12
Author(s):  
Christian Diamant Mossoro-Kpinde ◽  
Ralph-Sydney Mboumba Bouassa ◽  
Mohammad-Ali Jenabian ◽  
Serge Tonen Wolyec ◽  
Leman Robin ◽  
...  
Keyword(s):  
Real Time ◽  
Real Time Pcr ◽  
Dynamic Range ◽  
Limit Of Detection ◽  
Central Africa ◽  
Sub Saharan Africa ◽  
Clinical Samples ◽  
Absolute Bias ◽  
Sub Saharan ◽  
Hiv 1

Objectives. We evaluated the performances of Amplix real-time PCR platform developed by Biosynex (Strasbourg, France), combining automated station extraction (Amplix station 16 Dx) and real-time PCR (Amplix NG), for quantifying plasma HIV-1 RNA by lyophilized HIV-1 RNA-based Amplix reagents targeting gag and LTR, using samples from HIV-1-infected adults from Central African Republic. Results. Amplix real-time PCR assay showed low limit of detection (28 copies/mL), across wide dynamic range (1.4–10 log copies/mL), 100% sensitivity and 99% specificity, high reproducibility, and accuracy with mean bias < 5%. The assay showed excellent correlations and concordance of 95.3% with the reference HIV-1 RNA load assay (Roche), with mean absolute bias of +0.097 log copies/mL by Bland-Altman analysis. The assay was able to detect and quantify the most prevalent HIV-1 subtype strains and the majority of non-B subtypes, CRFs of HIV-1 group M, and HIV-1 groups N and O circulating in Central Africa. The Amplix assay showed 100% sensitivity and 99.6% specificity to diagnose virological failure in clinical samples from antiretroviral drug-experienced patients. Conclusions. The HIV-1 RNA-based Amplix real-time PCR platform constitutes sensitive and reliable system for clinical monitoring of HIV-1 RNA load in HIV-1-infected children and adults, particularly adapted to intermediate laboratory facilities in sub-Saharan Africa.

scholarly journals Development and evaluation of duplex TaqMan real-time PCR assay for detection and differentiation of wide-type and MGF505-2R gene-deleted African swine fever viruses

2020 ◽  
Author(s):  
zhenhua Guo ◽  
Kunpeng Li ◽  
Songlin Qiao ◽  
Xinxin Chen ◽  
Ruiguang Deng ◽  
...  
Keyword(s):  
Real Time ◽  
Real Time Pcr ◽  
Large Scale ◽  
Limit Of Detection ◽  
African Swine Fever ◽  
Economic Losses ◽  
Clinical Samples ◽  
Diagnosis Method ◽  
Pcr Method ◽  
And Control

Abstract Background: African swine fever (ASF) is the most important disease to the pigs and cause serious economic losses to the countries with large-scale swine production. Vaccines are recognized as the most useful tool to prevent and control ASF virus (ASFV) infection. Currently, the MGF505 and MGF360 gene-deleted ASFVs or combined with CD2v deletion were confirmed to be the most promising vaccine candidates. Thus, it is essential to develop a diagnosis method to discriminate wide-type strain from the vaccines used.Results: In this study, we established a duplex TaqMan real-time PCR based on the B646L gene and MGF505-2R gene. The sequence alignment showed that the targeted regions of primers and probes are highly conserved in the genotype II ASFVs. The duplex real-time assay can specifically detect B646L and MGF505-2R gene single or simultaneously without cross-reaction with other porcine viruses tested. The limit of detection was 5.8 copies and 3.0 copies for the standard plasmids containing B646L and MGF505-2R genes, respectively. Clinical samples were tested in parallel by duplex real-time PCR and a commercial ASFV detection kit. The detection results of these two assays against B646L gene were well consistent.Conclusion: We successfully developed and evaluated a duplex TaqMan real-time PCR method which can effectively distinguish the wide type and MGF505 gene-deleted ASFVs. It would be a useful tool for the clinical diagnosis and control of ASF.

Performance evaluation of cobas HBV real-time PCR assay on Roche cobas 4800 System in comparison with COBAS AmpliPrep/COBAS TaqMan HBV Test

2018 ◽  
Vol 56 (7) ◽  
pp. 1133-1139 ◽  
Author(s):  
Hanah Kim ◽  
Mina Hur ◽  
Eunsin Bae ◽  
Kyung-A Lee ◽  
Woo-In Lee
Keyword(s):  
Real Time ◽  
Real Time Pcr ◽  
Limit Of Detection ◽  
Nucleic Acid Amplification ◽  
Coefficient Of Determination ◽  
Clinical Samples ◽  
Pcr Assay ◽  
Cobas Taqman ◽  
Limit Of Quantitation ◽  
Two Systems

Abstract Background: Hepatitis B virus (HBV) nucleic acid amplification testing (NAAT) is important for the diagnosis and management of HBV infection. We evaluated the analytical performance of the cobas HBV NAAT (Roche Diagnostics GmbH, Mannheim, Germany) on the cobas 4800 System in comparison with COBAS AmpliPrep/COBAS TaqMan HBV Test (CAP/CTM HBV). Methods: Precision was evaluated using three levels of cobas HBV/HCV/HIV-1 Control Kit, and linearity was evaluated across the anticipated measuring range (10.0–1.0×109 IU/mL) at seven levels using clinical samples. Detection capability, including limit of blank (LOB), limit of detection (LOD) and limit of quantitation (LOQ), was verified using the 4th WHO International Standard for HBV DNA for NAT (NIBSC code: 10/266). Correlation between the two systems was compared using 205 clinical samples (102 sera and 103 EDTA plasma). Results: Repeatability and total imprecision (coefficient of variation) ranged from 0.5% to 3.8% and from 0.5% to 3.5%, respectively. Linearity (coefficient of determination, R2) was 0.999. LOB, LOD and LOQ were all acceptable within the observed proportion rate (85%). Correlation was very high between the two systems in both serum and plasma samples (correlation coefficient [r]=0.995). Conclusions: The new cobas HBV real-time PCR assay on the cobas 4800 System showed reliable analytical performances.

scholarly journals Validation of a real-time PCR assay for high-throughput detection of Avibacterium paragallinarum in chicken respiratory sites

2019 ◽  
Vol 31 (5) ◽  
pp. 714-718 ◽  
Author(s):  
Kristin A. Clothier ◽  
Simone Stoute ◽  
Andrea Torain ◽  
Beate Crossley
Keyword(s):  
Real Time ◽  
High Throughput ◽  
Real Time Pcr ◽  
Limit Of Detection ◽  
Bacterial Flora ◽  
Clinical Samples ◽  
Single Tube ◽  
Avibacterium Paragallinarum ◽  
Normal Bacterial Flora ◽  
Close Relatives

Avibacterium paragallinarum is the causative agent of infectious coryza, a highly contagious respiratory disease in chickens. Given its fastidious nature, this bacterium is difficult to recover and identify, particularly from locations colonized by normal bacterial flora. Standard PCR methods have been utilized for detection but are labor-intensive and not feasible for high-throughput testing. We evaluated a real-time PCR (rtPCR) method targeting the HPG-2 region of A. paragallinarum, and validated a high-throughput extraction for this assay. Using single-tube extraction, the rtPCR detected 4 A. paragallinarum (ATCC 29545T and 3 clinical) isolates with a limit of detection (LOD) of 10 cfu/mL and a PCR efficiency of 89–111%. Cross-reaction was not detected with 33 non– A. paragallinarum, all close relatives from the family Pasteurellaceae. Real-time PCR testing on extracts of 66 clinical samples (choana, sinus, or trachea) yielded 98.2% (35 of 36 on positives, 30 of 30 on negatives) agreement with conventional PCR. Duplicate samples tested in a 96-well format extraction in parallel with the single-tube method produced equivalent LOD on all A. paragallinarum isolates, and 96.8% agreement on 93 additional clinical samples extracted with both procedures. This A. paragallinarum rtPCR can be utilized for outbreak investigations and routine monitoring of susceptible flocks.

scholarly journals Development of Quantitative Real-Time PCR Assays for Detection and Quantification of Surrogate Biological Warfare Agents in Building Debris and Leachate

2007 ◽  
Vol 73 (20) ◽  
pp. 6557-6565 ◽  
Author(s):  
Pascal E. Saikaly ◽  
Morton A. Barlaz ◽  
Francis L. de los Reyes
Keyword(s):  
Real Time ◽  
Real Time Pcr ◽  
Genomic Dna ◽  
Dynamic Range ◽  
Limit Of Detection ◽  
Fate And Transport ◽  
Biological Warfare ◽  
Quantitative Real Time Pcr ◽  
Pcr Assays ◽  
Detection And Quantification

ABSTRACT Evaluation of the fate and transport of biological warfare (BW) agents in landfills requires the development of specific and sensitive detection assays. The objective of the current study was to develop and validate SYBR green quantitative real-time PCR (Q-PCR) assays for the specific detection and quantification of surrogate BW agents in synthetic building debris (SBD) and leachate. Bacillus atrophaeus (vegetative cells and spores) and Serratia marcescens were used as surrogates for Bacillus anthracis (anthrax) and Yersinia pestis (plague), respectively. The targets for SYBR green Q-PCR assays were the 16S-23S rRNA intergenic transcribed spacer (ITS) region and recA gene for B. atrophaeus and the gyrB, wzm, and recA genes for S. marcescens. All assays showed high specificity when tested against 5 ng of closely related Bacillus and Serratia nontarget DNA from 21 organisms. Several spore lysis methods that include a combination of one or more of freeze-thaw cycles, chemical lysis, hot detergent treatment, bead beat homogenization, and sonication were evaluated. All methods tested showed similar threshold cycle values. The limit of detection of the developed Q-PCR assays was determined using DNA extracted from a pure bacterial culture and DNA extracted from sterile water, leachate, and SBD samples spiked with increasing quantities of surrogates. The limit of detection for B. atrophaeus genomic DNA using the ITS and B. atrophaeus recA Q-PCR assays was 7.5 fg per PCR. The limits of detection of S. marcescens genomic DNA using the gyrB, wzm, and S. marcescens recA Q-PCR assays were 7.5 fg, 75 fg, and 7.5 fg per PCR, respectively. Quantification of B. atrophaeus vegetative cells and spores was linear (R 2 > 0.98) over a 7-log-unit dynamic range down to 101 B. atrophaeus cells or spores. Quantification of S. marcescens (R 2 > 0.98) was linear over a 6-log-unit dynamic range down to 102 S. marcescens cells. The developed Q-PCR assays are highly specific and sensitive and can be used for monitoring the fate and transport of the BW surrogates B. atrophaeus and S. marcescens in building debris and leachate.

Development of a LUX real-time PCR for the detection and quantification of human herpesvirus 7

2009 ◽  
Vol 55 (3) ◽  
pp. 319-325 ◽  
Author(s):  
Massimiliano Bergallo ◽  
Cristina Costa ◽  
Maria Elena Terlizzi ◽  
Francesca Sidoti ◽  
Samuela Margio ◽  
...  
Keyword(s):  
Real Time ◽  
Real Time Pcr ◽  
Primary Infection ◽  
Latent Infection ◽  
Dynamic Range ◽  
Human Herpesvirus ◽  
Clinical Samples ◽  
House Light ◽  
Pcr Assay ◽  
Sensitivity Specificity

Human herpesvirus 7 is a highly seroprevalent β-herpesvirus that, following primary infection, remains latent in CD4+ T cells and determines a persistent rather than a latent infection in various tissues and organs, including the lung and skin. This paper describes the development of an in-house light upon extension real-time PCR assay for quantification of human herpesvirus 7 DNA in clinical samples. The efficiency, sensitivity, specificity, inter- and intra-assay variability, and dynamic range have been determined. Subsequently, the assay has been validated by evaluating the human herpesvirus 7 load in bronchoalveolar lavages and skin specimens, chosen as 2 persistency sites, from healthy and pathological individuals. The real-time PCR assay developed in this study could be a useful tool to detect and quantify human herpesvirus 7 DNA in different clinical specimens to elucidate its epidemiological and pathogenic roles.

scholarly journals Comparative evaluation of two commercial real-time PCR kits (QuantiFast™ and abTES™) for the detection of Plasmodium knowlesi and other Plasmodium species in Sabah, Malaysia

2020 ◽  
Author(s):  
Nor Afizah Nuin ◽  
Angelica Fiona Tan ◽  
Yao Long Lew ◽  
Kim A Piera ◽  
Timothy William ◽  
...  
Keyword(s):  
Diagnostic Accuracy ◽  
Real Time ◽  
Real Time Pcr ◽  
Limit Of Detection ◽  
Plasmodium Knowlesi ◽  
Plasmodium Species ◽  
Detection Methods ◽  
Clinical Samples ◽  
Public Health Issue ◽  
Gene Target

Abstract Background : The monkey parasite Plasmodium knowlesi is an emerging public health issue in Southeast Asia. In Sabah, Malaysia, P. knowlesi is now the dominant cause of human malaria. Molecular detection methods for P. knowlesi are essential for accurate diagnosis and in monitoring progress towards malaria elimination of other Plasmodium species. However, recent commercially available PCR malaria kits have unpublished P. knowlesi gene targets or have not been evaluated against clinical samples. Methods : Two real-time PCR methods currently used in Sabah for confirmatory malaria diagnosis and surveillance reporting were evaluated: the QuantiFast™ Multiplex PCR kit (Qiagen, Germany) targeting the P. knowlesi 18S SSU rRNA; and the abTES™ Malaria 5 qPCR II kit (AITbiotech, Singapore), with an undisclosed P. knowlesi gene target. Diagnostic accuracy was evaluated using 52 P. knowlesi, 25 P. vivax , 21 P. falciparum , and 10 P. malariae clinical isolates, and 26 malaria negative controls, and compared against a validated reference nested PCR assay. The limit of detection (LOD) for each PCR method and Plasmodium species was also evaluated. Results : The sensitivity of the QuantiFast™ and abTES™ assays for detecting P. knowlesi was comparable at 98.1% (95%CI 89.7-100) and 100% (95%CI 93.2-100) respectively. Specificity of the QuantiFast™ and abTES™ for P. knowlesi was high at 98.8% (95%CI 93.4-100) for both assays. The QuantiFast™ assay demonstrated falsely-positive mixed Plasmodium species at low parasitaemias in both the primary and LOD analysis. Diagnostic accuracy of both PCR kits for detecting P. vivax , P. falciparum , and P. malariae was comparable to P. knowlesi . The abTES™ assay demonstrated a lower LOD for P. knowlesi of ≤0.125 parasites/µL compared to QuantiFast™ with a LOD of 20 parasites/µL. Hospital microscopy demonstrated a sensitivity of 78.8% (95%CI 65.3-88.9) and specificity of 80.4% (95%CI 67.6-89.8) compared to reference PCR for detecting P. knowlesi . Conclusion : The QuantiFast™ and abTES™ commercial PCR kits performed well for the accurate detection of P. knowlesi infections. Although the QuantiFast™ kit is cheaper, the abTES™ kit demonstrated a lower LOD, supporting its use as a second-line referral-laboratory diagnostic tool in Sabah, Malaysia.

scholarly journals Development and evaluation of duplex TaqMan real-time PCR assay for detection and differentiation of wide-type and MGF505-2R gene-deleted African swine fever viruses

2020 ◽  
Vol 16 (1) ◽  
Author(s):  
Zhenhua Guo ◽  
Kunpeng Li ◽  
Songlin Qiao ◽  
Xin-xin Chen ◽  
Ruiguang Deng ◽  
...  
Keyword(s):  
Real Time ◽  
Real Time Pcr ◽  
Large Scale ◽  
Limit Of Detection ◽  
African Swine Fever ◽  
Economic Losses ◽  
Clinical Samples ◽  
Diagnosis Method ◽  
Pcr Method ◽  
And Control

Abstract Background African swine fever (ASF) is the most important disease to the pigs and cause serious economic losses to the countries with large-scale swine production. Vaccines are recognized as the most useful tool to prevent and control ASF virus (ASFV) infection. Currently, the MGF505 and MGF360 gene-deleted ASFVs or combined with CD2v deletion were confirmed to be the most promising vaccine candidates. Thus, it is essential to develop a diagnosis method to discriminate wide-type strain from the vaccines used. Results In this study, we established a duplex TaqMan real-time PCR based on the B646L gene and MGF505-2R gene. The sequence alignment showed that the targeted regions of primers and probes are highly conserved in the genotype II ASFVs. The duplex real-time assay can specifically detect B646L and MGF505-2R gene single or simultaneously without cross-reaction with other porcine viruses tested. The limit of detection was 5.8 copies and 3.0 copies for the standard plasmids containing B646L and MGF505-2R genes, respectively. Clinical samples were tested in parallel by duplex real-time PCR and a commercial ASFV detection kit. The detection results of these two assays against B646L gene were well consistent. Conclusion We successfully developed and evaluated a duplex TaqMan real-time PCR method which can effectively distinguish the wide type and MGF505 gene-deleted ASFVs. It would be a useful tool for the clinical diagnosis and control of ASF.

scholarly journals Development and Evaluation of Duplex TaqMan Real-Time PCR Assay for Detection and Differentiation of Wide-Type and MGF505 Gene-Deleted African Swine Fever Viruses

2020 ◽  
Author(s):  
Zhenhua Guo ◽  
Kunpeng Li ◽  
Songlin Qiao ◽  
Xinxin Chen ◽  
Ruiguang Deng ◽  
...  
Keyword(s):  
Real Time ◽  
Real Time Pcr ◽  
Large Scale ◽  
Limit Of Detection ◽  
African Swine Fever ◽  
Economic Losses ◽  
Clinical Samples ◽  
Diagnosis Method ◽  
Pcr Method ◽  
And Control

Abstract Background: African swine fever (ASF) is the most important disease to the pigs and cause serious economic losses to the countries with large-scale swine production. Vaccines are recognized as the most useful tool to prevent and control ASF virus (ASFV) infection. Currently, the MGF505 and MGF360 gene-deleted ASFVs or combined with CD2v deletion were confirmed to be the most promising vaccine candidates. Thus, it is essential to develop a diagnosis method to discriminate wide-type strain from the vaccines used. Results: In this study, we established a duplex TaqMan real-time PCR based on the B646L gene and MGF505-2R gene. The sequence alignment showed that the targeted regions of primers and probes are highly conserved in the genotype II ASFVs. The duplex real-time assay can specifically detect B646L and MGF505-2R gene single or simultaneously without cross-reaction with other porcine viruses tested. The limit of detection was 5.8 copies and 3.0 copies for the standard plasmids containing B646L and MGF505-2R genes, respectively. Clinical samples were tested in parallel by duplex real-time PCR and a commercial ASFV detection kit. The detection results of these two assays against B646L gene were well consistent. Conclusion: We successfully developed and evaluated a duplex TaqMan real-time PCR method which can effectively distinguish the wide type and MGF505 gene-deleted ASFVs. It would be a useful tool for the clinical diagnosis and control of ASF.

scholarly journals Accuracy of Curable Sexually Transmitted Infections and Genital Mycoplasmas Screening by Multiplex Real-Time PCR Using a Self-Collected Veil among Adult Women in Sub-Saharan Africa

2019 ◽  
Vol 2019 ◽  
pp. 1-15
Author(s):  
Zita Aleyo Nodjikouambaye ◽  
Fabrice Compain ◽  
Damtheou Sadjoli ◽  
Ralph-Sydney Mboumba Bouassa ◽  
Hélène Péré ◽  
...  
Keyword(s):  
Sexually Transmitted Infections ◽  
Real Time ◽  
Real Time Pcr ◽  
Sub Saharan Africa ◽  
Molecular Testing ◽  
Adult Women ◽  
Sampling Device ◽  
Sexually Transmitted ◽  
Sub Saharan ◽  
Genital Mycoplasmas

Background. Sexually transmitted infections (STIs) are highly prevalent in sub-Saharan Africa. Genital self-sampling may facilitate the screening of STIs in hard-to-reach remote populations far from large health care centers and may increase screening rates. The cross-sectional GYNAUTO-STI study was carried out to assess the performance of a novel genital veil (V-Veil-Up Gyn Collection Device, V-Veil-Up Pharma, Ltd., Nicosia, Cyprus) as a genital self-sampling device to collect genital secretions to diagnose STIs by molecular biology as compared to reference clinician-collected genital specimens, in adult African women. Methods. Adult women living in N’Djamena, the capital city of Chad, were recruited from the community and referred to the clinic for women’s sexual health “La Renaissance Plus”. A clinician obtained an endocervical specimen using flocked swab. Genital secretions were also obtained by self-collection using veil. Both clinician- and self-collected specimens were tested for common curable STIs (including Chlamydia trachomatis, Neisseria gonorrhoeae, Mycoplasma genitalium, and Trichomonas vaginalis) and genital Mycoplasma spp. by multiplex real-time PCR (Allplex™ STI Essential Assay, Seegene, Seoul, South Korea). Test positivities for both collection methods were compared by assessing methods agreement, sensitivity, and specificity. Results. A total of 251 women (mean age, 35.1 years) were prospectively enrolled. Only seven (2.8%) women were found to be infected with at least one common STIs [C. trachomatis: 3 (1.2%), N. gonorrhoeae: 1 (0.4%), M. genitalium: 4 (1.6%) and T. vaginalis: 1 (0.4%)], while the prevalence of genital mycoplasmas was much higher (54.2%) with a predominance of Ureaplasma parvum (42.6%). Self-collection by veil was non-inferior to clinician-based collection for genital microorganisms DNA molecular testing, with “almost perfect” agreement between both methods, high sensitivity (97.0%; 95%CI: 92.5-99.2%), and specificity (88.0%; 95%CI: 80.7-93.3%). Remarkably, the mean total number of genital microorganisms detected per woman was 1.14-fold higher in self-collected specimens compared to that in clinician-collected specimens. Conclusions. Veil-based self-collection of female genital secretions constitutes a convenient tool to collect in gentle way cervicovaginal secretions for accurate molecular detection of genital bacteria. Such sampling procedure could be easily implemented in STIs clinics in sub-Saharan Africa.

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