scholarly journals Comparison of SARS-CoV2 N gene real-time RT-PCR targets and commercially available mastermixes

2020 ◽  
Author(s):  
Julianne R Brown ◽  
Denise O’Sullivan ◽  
Rui PA Pereira ◽  
Alexandra S Whale ◽  
Eloise Busby ◽  
...  
Keyword(s):  
Real Time ◽  
Lower Limit ◽  
Real Time Pcr ◽  
Limit Of Detection ◽  
N Gene ◽  
Rt Pcr ◽  
One Step ◽  
Improved Performance ◽  
Rna Transcript ◽  
Nose And Throat

ABSTRACTWe aim to test four one-step RT real-time mastermix options for use in SARS-CoV2 real-time PCR, with three primer/probe assays targeting the N gene. The lower limit of detection is determined using a SARS CoV2 N gene RNA transcript dilution series (to 1 copy/µl) and verified using 74 nose and throat swabs.The N2 assay demonstrates the most sensitive detection of SARS-Cov-2 RNA. Three of the four mastermixes performed well, with the Takara One Step PrimeScript™ III RT-PCR Kit mastermix demonstrating improved performance at the lower limit of detection.

scholarly journals Comparison of a one-step real-time RT-PCR and a nested real-time RT-PCR for a genogroup II norovirus reveals differences in sensitivity depending upon assay design and visualization

PLoS ONE ◽  
2021 ◽  
Vol 16 (4) ◽  
pp. e0248581
Author(s):  
Clyde S. Manuel ◽  
Cassandra Suther ◽  
Matthew D. Moore ◽  
Lee-Ann Jaykus
Keyword(s):  
Detection Limit ◽  
Real Time ◽  
Real Time Pcr ◽  
Environmental Samples ◽  
Blot Hybridization ◽  
Molecular Techniques ◽  
Rt Pcr ◽  
Dot Blot ◽  
Dot Blot Hybridization ◽  
One Step

Human norovirus (NoV) is the leading cause of acute viral gastroenteritis and a major source of foodborne illness. Detection of NoV in food and environmental samples is typically performed using molecular techniques, including real-time reverse transcription polymerase chain reaction (RT-PCR) and less frequently, nested real-time PCR. In this study, we conducted a controlled comparison of two published NoV detection assays: a broadly reactive one-step real-time RT-PCR and a two-step nested real-time PCR assay. A 20% human fecal suspension containing a genogroup II human NoV was serially diluted, genome extracted, and subjected to amplification using the two assays compared via PCR Units. Additional amplicon confirmation was performed by dot blot hybridization using digoxigenin (DIG)-labeled oligonucleotide probes. Both assays displayed similar amplification standard curves/amplification efficiencies; however, the nested assay consistently detected one log10 lower virus. Dot blot hybridization improved the detection limit of the nested real-time PCR by one log10 NoV genome copies but impaired the detection limit of the one-step real-time RT-PCR by one log10 NoV genome copies. These results illustrate the complexities in designing and interpreting molecular techniques having a sufficient detection limit to detect low levels of viruses that might be anticipated in contaminated food and environmental samples.

scholarly journals Direct detection of Dengue viruses without extraction of RNA on the mobile real-time PCR device

2020 ◽  
Author(s):  
Masaaki Muraoka ◽  
Yukiko Tanoi ◽  
Tetsutaro Tada ◽  
Aya Tabata ◽  
Mikio Mizukoshi ◽  
...  
Keyword(s):  
Real Time ◽  
Real Time Pcr ◽  
Direct Detection ◽  
Positive Control ◽  
Nucleic Acid Amplification ◽  
Severe Dengue ◽  
Mosquito Vectors ◽  
Rt Pcr ◽  
The Real ◽  
One Step

ABSTRACTDengue virus (DENV) is the cause of dengue / severe dengue and a virus of the Flaviviridae family, furthermore, dengue fever has rapidly spread in the world in recent decades. DENV is transmitted by female mosquitoes, mainly of the specie Aedes aegypti. The main method to control or prevent the transmission of DENV is to combat the mosquito vectors. Among these, one of important methods is to monitor the DENVs in the mosquito vectors.For the detection of DENV, nucleic acid amplification tests (NAAT) were recommended, of which criterion standard is real-time RT-PCR with highly sensitive and specific. However, it takes long time as to judge the result per a reaction, besides the necessity of the treatment of RNA in advance, example of extraction, concentration and purification.It was our object in this time to develop the method of real-time RT-PCR detecting DENVs in shorter time, moreover without especial treatment of RNA from the mosquito in advance. Besides, this work was performed with combing the mobile real-time PCR device with the one-step RT-PCR reagent.Firstly, we succeeded in shortening the time of real-time RT-PCR for the detection of DENV per one reaction, so that the judgement needed less than 20 minutes if genomic RNA treated in advance. Moreover, each value on the real-PCR device was quantitatively correlated with the positive control RNA from 1.0 × 10 ^ 3 copies to 1.0 × 10 ^ 0 copies per reaction (This correlation coefficient R2 > 0.95). Additionally, it made sure that this method could be applied to each DENV serotype.Secondly, we established the basis of procedure for the real-time RT-PCR without the treatment in advance so-called “direct”. As the result that the positive control RNA additive was utilized instead of the real DENV, spiked into the mosquito homogenized and sampled the supernatant without treatment, it was possible to detect on the real-time RT-PCR even if mosquitoes immediately after blood-feeding. For this reason, this method might be able to utilize in human sera, too.According to the results of this work, we could suggest the method is possible to detect DENV more quickly and more simply than heretofore. The Real-time “direct” RT-PCR, especially, could be performed with mobile real-time PCR PCR1100 device and one step RT-PCR reagent only. This method must help to detect some viruses other than DENV, too.

scholarly journals Development of a Real-Time PCR Assay for Identification of Coccidioides immitis by Use of the BD Max System: TABLE 1

2015 ◽  
Vol 53 (3) ◽  
pp. 926-929 ◽  
Author(s):  
Marilyn Mitchell ◽  
Dominic Dizon ◽  
Robert Libke ◽  
Michael Peterson ◽  
David Slater ◽  
...  
Keyword(s):  
Sample Preparation ◽  
Real Time ◽  
Real Time Pcr ◽  
Limit Of Detection ◽  
Hospital Setting ◽  
Internal Standard ◽  
Specimen Preparation ◽  
Coccidioides Immitis ◽  
Rt Pcr ◽  
Content Type

Rapid real-time PCR (RT-PCR) can be performed in a community hospital setting to identifyCoccidioidesspecies using the new Becton Dickinson molecular instrument BD Max. Following sample preparation, DNA extraction and PCR were performed on the BD Max using the BD Max extraction kit ExK-DNA-1 test strip and a master mix prepared by BioGX (Birmingham, AL). Sample preparation took 2 h, and testing on the BD Max took an additional 2 h. Method sensitivity and specificity were evaluated along with the limits of detection to confirm that this convenient method would provide medically useful information. Using serial dilutions, the lower limit of detection was determined to be 1 CFU/μl. Testing with this method was validated using samples from various body sites, including bronchial alveolar lavage (BAL) fluid; sputum and lung tissue samples; and pleural and spinal fluids. Safety protocols were established, and specimen preparation processes were developed for the various types of specimens. The range for the cycle threshold (CT) indicating adequate fluorescent signal to signify a positive result was established along with the acceptable range for the internal standard. Positive controls run with each batch were prepared by spiking a pooled BAL fluid specimen with a known dilution ofCoccidioides immitisorganism. Our experience with testing >330 patient samples shows that clinically relevant information can be available within 4 h using an RT-PCR method on the BD Max to identifyCoccidioidesspp., with sensitivity equivalent to culture.

scholarly journals Comparison of real-time RT-PCR and RT-PCR/MALDI-TOF methods for SARS-CoV-2 detection in saliva

2021 ◽  
Vol 156 (Supplement_1) ◽  
pp. S9-S9
Author(s):  
Matthew M Hernandez ◽  
Radhika Banu ◽  
Paras Shrestha ◽  
Armi Patel ◽  
Feng Chen ◽  
...  
Keyword(s):  
Real Time ◽  
Limit Of Detection ◽  
High Sensitivity ◽  
N Gene ◽  
Rt Pcr ◽  
Upper Respiratory ◽  
High Level ◽  
Respiratory Specimens ◽  
Pcr Test ◽  
Roche Cobas

Abstract Background The coronavirus disease 2019 pandemic has accelerated the need for rapid validation and implementation of assays for detection of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) in diagnostic specimens. Multiple molecular methods have received emergency use authorization by the U.S. Food and Drug Administration for detection of SARS-CoV-2 in upper respiratory specimens, with testing of nasopharyngeal (NP) specimens serving as the foundation for these assays. However, supply chain constraints and the need for improved ease and safety of collection have prompted consideration of other specimen types as alternatives to NP specimens for detection of SARS-CoV-2. Here, we compared two methods for SARS-CoV-2 detection in saliva: the Roche cobas® 6800 SARS-CoV-2 real-time RT-PCR Test (“Roche”), which tests for viral ORF1ab (target 1, T1) and envelope E genes (target 2, T2); and the Agena Biosciences MassARRAY® SARS-CoV-2 Panel/MassARRAY® System (“Agena”), which tests for targets in the ORF1ab gene (ORF1, Orf1ab) and nucleocapsid N gene (N1, N2, N3). Methods Sixty saliva specimens collected within 48 hours of SARS-CoV-2 detection in an upper respiratory (anterior nares or NP) specimen from the same individual were tested in both the Roche and Agena platforms. Each system was evaluated for overall detection results and agreement with results of matched upper respiratory specimens. In addition, we determined the limit of detection (LoD) for each system and its component targets using an in-house SARS-CoV-2 standard generated from pooled positive saliva specimens quantitated against a commercially available standard (ZeptoMetrix NATSARS(COV2)-ERC). Results Both platforms demonstrated a similarly high sensitivity (97%) and specificity (100%) when compared to matched patient upper respiratory specimens and had high agreement with one another (Cohen’s κ = 0.9321, p = 2.6x10-13). Overall, the LoD (copies/mL) for the Roche assay was four times lower than that of Agena for saliva specimens (390.6 v. 1562.5). Furthermore, we determined that the LoD differed among the target components of each assay. The experimental LoD was comparable across Roche targets, but probit analyses indicate T2 has greater sensitivity (LoD: 228.6), Of the five Agena targets, the N2 target had the lowest LoD (1562.5). Conclusions In sum, we demonstrate that saliva is an acceptable specimen for testing in both the Roche cobas® 6800 SARS-CoV-2 real-time RT-PCR Test and the Agena Biosciences MassARRAY® SARS-CoV-2 Panel/MassARRAY® System, and both provide sensitive and specific detection of SARS-CoV-2 in saliva specimens. Although there was a high level of agreement between platforms, the LoD was lower for the Roche compared to the Agena assay with T2 and N2 being the most sensitive targets on each platform, respectively. The addition of saliva as an acceptable specimen and understanding the sensitivity for testing on these platforms can further inform public health measures for screening and detection to combat the pandemic.

scholarly journals Quickly and simply detection for coronaviruses including SARS-CoV-2 on the mobile Real-Time PCR without treating RNA in advance

2020 ◽  
Author(s):  
Masaaki Muraoka ◽  
Yukiko Tanoi ◽  
Tetsutaro Tada ◽  
Mikio Mizukoshi ◽  
Osamu Kawaguchi
Keyword(s):  
Real Time ◽  
Correlation Coefficient ◽  
Real Time Pcr ◽  
Positive Control ◽  
List Type ◽  
Rt Pcr ◽  
Human Coronavirus ◽  
One Step ◽  
Short Time ◽  
Human Coronavirus 229E

ABSTRACTSARS-CoV-2 was reported to the WHO as an outbreak in Wuhan City, China on end of 2019, afterwards pandemic on the worldwide in 2020. The SARS-CoV-2 virus is less deadly, but far more transmissible. Therefore, it needs to detect and monitor quickly and simply on site to prevent SARS-CoV-2.If detecting coronaviruses including SARS-CoV-2, the real-time RT-PCR method is sensitive and specific for the unique target, however, it must take long time and labour that RNA is treated in advance, transcribed and amplified. Therefore, referenced previously report, in this study, we modified various methods to prove hypotheses the followed.Firstly, we hypothesized that real-time RT-PCR could be finished in very short time by the mobile real-time PCR device and one-step RT-PCR reagent. Secondly, we hypothesized that it was possible to perform RT-PCR utilizing the reagent as the above without RNA treatment in advance so called “direct”.Firstly, it was able to detect the positive control RNA of SARS-CoV-2 for less than 13.5 minutes by primer-probe referring to the CDC. Moreover, each detection value varied in accordance with each concentration (This correlation coefficient R2 > 0.95). Secondary, it was possible to detect human coronavirus 229E with direct RT-PCR. Furthermore, each detection value varied in accordance with each titer (TCID50 / mL) of human coronavirus 229E (This correlation coefficient R2 > 0.95).Considering the above, causing by utilizing the mobile real-time PCR device and the one-step real-time PCR reagent simultaneously following as: 1) It was possible to detect SARS-CoV-2 in very short time as compared to conventional method; 2) It was possible to detect human coronavirus quickly and simply with “direct”. For these reasons, we hypothesized that it is possible to detect SARS-CoV-2 quickly and simply by utilizing methods the above without treating RNA in advance. This hypothesis is our next try.STRENGTHS AND LIMITATIONS OF THIS STUDY*This study developed it possible to detect the positive control RNA of SARS-CoV-2 more quickly than previously, however couldn’t try to detect the genetic RNA.*This study proved clearly that the human coronavirus instead of SARS-CoV-2 could be detected simply without treating RNA in advance by the same method above.*This study couldn’t try to utilize the human specimens because of our institution limited.*This study could utilize the device and the reagents commercial and not especial.

scholarly journals In-house modification and improvement of the CDC real-time PCR diagnostic assay for SARS-CoV-2 detection.

2020 ◽  
Author(s):  
Srirupa Das ◽  
Candice Dowell-Martino ◽  
Lisa Arrigo ◽  
Paul N. Fiedler ◽  
Sandra Lobo
Keyword(s):  
Real Time ◽  
Health Care Providers ◽  
Real Time Pcr ◽  
Diagnostic Tests ◽  
Limit Of Detection ◽  
World Health ◽  
Diagnostic Assay ◽  
Care Providers ◽  
Rt Pcr ◽  
The World

The world is currently facing an unprecedented pandemic caused by the novel coronavirus SARS-CoV-2 (COVID-19) which was first reported in late 2019 by China to the World Health Organization (WHO). The containment strategy for COVID-19, which has non-specific flu-like symptoms and where upwards of 80% of the affected has either mild or no symptoms, is critically centered upon diagnostic testing, tracking and isolation. Thus, the development of specific and sensitive diagnostic tests for COVID-19 is key towards the first successful step of disease management. Public health organizations like the WHO and the US-based Centers for Disease Control and Prevention (CDC) have developed real-time PCR (RT-PCR) based diagnostic tests to aid in the detection of acute infection. In this study we sought to modify the CDC RT-PCR diagnostic assay protocol to increase its sensitivity and to make the assay directly portable to health care providers in a community-based hospital setting. A number of modifications to the original protocol were tested. Increasing the RT-PCR annealing temperature by 7°C to 62°C was associated with the most significant improvement in sensitivity, wherein the cycle-threshold (Ct) value for the N2 assay was reduced by ~3 units, in effect both reducing the overall number of inconclusive results and yielding N1/N2 assays to have similar Ct values. The limit of detection of the modified assay was also improved (0.86 RNA copies/μl for both nCoV 2019_N1/N2 assays) compared to the CDC RT-PCR diagnostic assay (1 and 3.16 RNA copies/μl for nCoV 2019_N1 and N2 assay, respectively). Using this modification, there was no significant effect on SARS-CoV-2 detection rate when viral RNA extraction was performed either manually or through an automated extraction method. We believe this modified protocol allows for more sensitive detection of the virus which in turn will be useful for pandemic management.

scholarly journals Development and comparison of novel multiple cross displacement amplification (MCDA) assays with other nucleic acid amplification methods for SARS-CoV-2 detection

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Laurence Don Wai Luu ◽  
Michael Payne ◽  
Xiaomei Zhang ◽  
Lijuan Luo ◽  
Ruiting Lan
Keyword(s):  
Nucleic Acid ◽  
Real Time Pcr ◽  
Limit Of Detection ◽  
Isothermal Amplification ◽  
Nucleic Acid Amplification ◽  
N Gene ◽  
Rt Pcr ◽  
Amplification Method ◽  
Multiple Cross ◽  
Time To Detection

AbstractThe development of alternative isothermal amplification assays including multiple cross displacement amplification (MCDA) may address speed and portability limitations of real-time PCR (rt-PCR) methods for SARS-CoV-2 detection. We developed a novel SARS-CoV-2 MCDA assay and compared its speed and sensitivity to loop-mediated isothermal amplification (LAMP) and rt-PCR. Two MCDA assays targeting SARS-CoV-2 N gene and ORF1ab were designed. The fastest time to detection and sensitivity of MCDA was compared to LAMP and rt-PCR using DNA standards and transcribed RNA. For the N gene, MCDA was faster than LAMP and rt-PCR by 10 and 20 min, respectively with fastest time to detection at 5.2 min. rt-PCR had the highest sensitivity with the limit of detection at 10 copies/µl compared with MCDA (100 copies/µl) and LAMP (500 copies/µl). For ORF1ab, MCDA and LAMP had similar speed with fastest time to detection at 9.7 and 8.4 min, respectively. LAMP was more sensitive for ORF1ab detection with 50 copies/µl compared to MCDA (500 copies/µl). In conclusion, different nucleic acid amplification methods provide different advantages. MCDA is the fastest nucleic acid amplification method for SARS-CoV-2 while rt-PCR is the most sensitive. These advantages should be considered when determining the most suitable nucleic acid amplification methods for different applications.

scholarly journals Development and Evaluation of AccuPower® COVID-19 Multiplex Real-Time RT-PCR Kit and AccuPower® SARS-CoV-2 Multiplex Real-Time RT-PCR Kit for SARS-CoV-2 Detection in Sputum, NPS/OPS, Saliva and Pooled Samples

2021 ◽  
Author(s):  
In Bum Suh ◽  
Jaegyun Lim ◽  
Hyo Seon Kim ◽  
Guil Rhim ◽  
Heebum Kim ◽  
...  
Keyword(s):  
Real Time ◽  
Limit Of Detection ◽  
Clinical Performance ◽  
Rna Extraction ◽  
Kappa Coefficient ◽  
N Gene ◽  
Clinical Samples ◽  
Rt Pcr ◽  
Current Standard ◽  
Pooled Samples

Rapid and accurate detection of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is essential for the successful control of the current global COVID-19 pandemic. The real-time reverse transcription polymerase chain reaction (Real-time RT-PCR) is the most widely used detection technique. This research describes the development of two novel multiplex real-time RT-PCR kits, AccuPower ® COVID-19 Multiplex Real-Time RT-PCR Kit (NCVM) specifically designed for use with the ExiStation ™48 system (comprised of ExiPrep ™48 Dx and Exicycler ™96 by BIONEER, Korea) for sample RNA extraction and PCR detection, and AccuPower ® SARS-CoV-2 Multiplex Real-Time RT-PCR Kit (SCVM) designed to be compatible with manufacturers` on-market PCR instruments. The limit of detection (LoD) of SCVM was 2 copies/µ L and the LoD of the NCVM was 120 copies/mL for both the gene and the SARS-CoV-2 gene (N gene and RdRp gene). The AccuPower ® kits demonstrated high precision with no cross reactivity to other respiratory-related microorganisms. The clinical performance of AccuPower ® kits was evaluated using the following clinical samples: sputum and nasopharyngeal/oropharyngeal swab (NPS/OPS) samples. Overall agreement of the AccuPower ® kits with a Food and Drug Administration (FDA) approved emergency use authorized commercial kit (STANDARD ™ M nCoV Real-Time Detection kit, SD BIOSENSOR, Korea) was above 95% (Cohen`s kappa coefficient ≥ 0.95), with a sensitivity of over 95%. The NPS/OPS specimen pooling experiment was conducted to verify the usability of AccuPower ® kits on pooled samples and the results showed greater than 90% agreement with individual NPS/OPS samples. The clinical performance of AccuPower ® kits with saliva samples was also compared with NPS/OPS samples and demonstrated over 95% agreement (Cohen`s kappa coefficient > 0.95). This study shows the BIONEER NCVM and SCVM assays are comparable with the current standard confirmation assay and are suitable for effective clinical management and control of SARS-CoV-2.

scholarly journals Real-Time PCR Assay for Rapid and Simultaneous Detection of vanA and vanB Genes in Clinical Strains

Diagnostics ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 2081
Author(s):  
Hanane Zerrouki ◽  
Sid-Ahmed Rebiahi ◽  
Linda Hadjadj ◽  
Jean-Marc Rolain ◽  
Seydina M. Diene
Keyword(s):  
Real Time ◽  
Real Time Pcr ◽  
Limit Of Detection ◽  
Bacterial Species ◽  
Simultaneous Detection ◽  
Rt Pcr ◽  
Pcr Assay ◽  
Surveillance Programs ◽  
Blastn Analysis ◽  
Vancomycin Resistant

Here, we develop a robust and sensitive real-time PCR assay which allows the simultaneous detection of vanA and vanB genes using common primers. The system was designed using the Primer3 online software. The specificity of primers and probes was first checked by in silico PCR and by BlastN analysis. The genomic DNA of 255 bacterial isolates, including Enterococcus spp., Gram-negative, and Gram-positive strains, as well as a collection of 50 stool and 50 rectal swab samples, were tested to evaluate the specificity of the new real-time PCR (RT-PCR) system. The results of the designed RT-PCR were 100% specific and 100% positive on tested vancomycin resistant isolates harboring either the vanA or vanB gene. RT-PCR assays were negative for all other bacterial species tested including vancomycin-sensitive Enterococci and Enterococcus strains harboring vanC genes. The limit of detection of vanA and vanB genes by RT-PCR assay was 47 CFU/mL and 32 CFU/mL, respectively. The rapid and accurate detection of vancomycin-resistant Enterococci is the cornerstone for minimizing the risk of nosocomial transmissions and outbreaks. We believe that this assay will strengthen routine diagnostics and surveillance programs.

Sign in / Sign up

Export Citation Format

Share Document