Quantification of SARS-CoV-2 variant mutations (HV69-70, E484K/N501Y, and del156-157/R158G) in settled solids using digital RT-PCR v2

Author(s):  
Bridgette Hughes ◽  
Bradley J. White ◽  
Marlene K. Wolfe ◽  
Krista Wigginton ◽  
Alexandria B Boehm

This process instruction describes the steps for quantitative analysis of nucleic acid from SARS-CoV-2 with a triplex Reverse Transcriptase droplet digital Polymerase Chain Reaction (RT-ddPCR) assay targeting the N Gene, S Gene and 3 mutation assays (one for HV69-70, one for E484K/N501Y, and one for del156-157/R158G) in extracted and purified RNA samples from solid wastewater samples for population level SARS-CoV-2 community surveillance. RT-ddPCR is a modified version of conventional RT-PCR workflows which involves separating the reaction mixture into many partitions (~20,000) before thermal cycling which allows for direct absolute quantification of the target RNA molecules. Future protocols will be published that are complementary to this one and describe assays targeting additional SARS-CoV-2 mutations. This protocol uses RNA extracted using this protocol: High Throughput RNA Extraction and PCR Inhibitor Removal of Settled Solids for Wastewater Surveillance of SARS-CoV-2 RNA. That RNA is generated from samples subjected to pre-analytical steps outlined in: High Throughput pre-analytical processing of wastewater settled solids for SARS-CoV-2 RNA analyses. It is recommended that these assays be run along assays for PMMoV and BCoV as controls as described in the companion protocol High Throughput SARS-COV-2, PMMOV, and BCoV quantification in settled solids using digital RT-PCR The readout of this assay is a concentration of each target in the extracted RNA samples (copies/µL). Scope This process instruction applies to quantitative analysis of nucleic acid from SARS-CoV-2 RNA from solid wastewater samples with ddPCR using a Bio-Rad AutoDG Droplet Digital PCR system consisting of the AutoDG Automated Droplet Generator and the QX200 droplet reader.

2021 ◽  
Author(s):  
Bridgette Hughes ◽  
Bradley J. White ◽  
Marlene K. Wolfe ◽  
Krista Wigginton ◽  
Alexandria B Boehm

This process instruction describes the steps for quantitative analysis of nucleic acid from SARS-CoV-2 with a triplex Reverse Transcriptase droplet digital Polymerase Chain Reaction (RT-ddPCR) assay targeting the N Gene, S Gene and 3 mutation assays (one each for HV69-70, E484K/N501Y, del156-157/R158G, and Del143-145) in extracted and purified RNA samples from solid wastewater samples for population level SARS-CoV-2 community surveillance. RT-ddPCR is a modified version of conventional RT-PCR workflows which involves separating the reaction mixture into many partitions (~20,000) before thermal cycling which allows for direct absolute quantification of the target RNA molecules. Future protocols will be published that are complementary to this one and describe assays targeting additional SARS-CoV-2 mutations. This protocol uses RNA extracted using this protocol: High Throughput RNA Extraction and PCR Inhibitor Removal of Settled Solids for Wastewater Surveillance of SARS-CoV-2 RNA. That RNA is generated from samples subjected to pre-analytical steps outlined in: High Throughput pre-analytical processing of wastewater settled solids for SARS-CoV-2 RNA analyses. It is recommended that these assays be run along assays for PMMoV and BCoV as controls as described in the companion protocol High Throughput SARS-COV-2, PMMOV, and BCoV quantification in settled solids using digital RT-PCR The readout of this assay is a concentration of each target in the extracted RNA samples (copies/µL). Scope This process instruction applies to quantitative analysis of nucleic acid from SARS-CoV-2 RNA from solid wastewater samples with ddPCR using a Bio-Rad AutoDG Droplet Digital PCR system consisting of the AutoDG Automated Droplet Generator and the QX200 droplet reader.


2021 ◽  
Author(s):  
Aaron Topol (Verily Life Sciences) ◽  
marlene.wolfe not provided ◽  
Brad White (Verily Life Sciences) ◽  
Krista Wigginton ◽  
Alexandria B Boehm

This process instruction describes the steps for quantitative analysis of nucleic acid from SARS-CoV-2 with a triplex Reverse Transcriptase droplet digital Polymerase Chain Reaction (RT-ddPCR) assay targeting the N Gene, S Gene and ORF1a and a duplex assay targeting Bovine Coronavirus Vaccine (BCoV) and Pepper Mild mottle virus (PMMoV) in extracted and purified RNA samples from solid wastewater samples for population level SARS-CoV-2 community surveillance. RT-ddPCR is a modified version of conventional RT-PCR workflows which involves separating the reaction mixture into many partitions (~20,000) before thermal cycling which allows for direct absolute quantification of the target RNA molecules. This protocol uses RNA extracted using this protocol: High Throughput RNA Extraction and PCR Inhibitor Removal of Settled Solids for Wastewater Surveillance of SARS-CoV-2 RNA. That RNA is generated from samples subjected to pre-analytical steps outlined in: High Throughput pre-analytical processing of wastewater settled solids for SARS-CoV-2 RNA analyses. This protocol describes 2 separate PCR reactions, one containing primer/probe mixtures targeting the three SARS-CoV-2 targets and one containing primer/probe mixtures targeting BCoV and PMMoV. BCoV is spiked into samples before nucleic acid extraction and serves as a process control as well as an indicator of PCR inhibition. PMMoV is an enveloped virus which is abundant in human fecal waste and serves as an endogenous control for data normalization. PMMoV RNA is abundant at such high levels in wastewater samples that the samples must be diluted by a factor of 100 before quantification. The readout of this assay is a concentration of each target in the extracted RNA samples (copies/uL). Scope This process instruction applies to quantitative analysis of nucleic acid from SARS-CoV-2 RNA from solid wastewater samples with ddPCR using a Bio-Rad AutoDG Droplet Digital PCR system consisting of the AutoDG Automated Droplet Generator and the QX200 droplet reader.


Viruses ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 615
Author(s):  
Allen Wing-Ho Chu ◽  
Cyril Chik-Yan Yip ◽  
Wan-Mui Chan ◽  
Anthony Chin-Ki Ng ◽  
Dream Lok-Sze Chan ◽  
...  

SARS-CoV-2 RT-PCR with pooled specimens has been implemented during the COVID-19 pandemic as a cost- and manpower-saving strategy for large-scale testing. However, there is a paucity of data on the efficiency of different nucleic acid extraction platforms on pooled specimens. This study compared a novel automated high-throughput liquid-based RNA extraction (LRE) platform (PHASIFYTM) with a widely used magnetic bead-based total nucleic acid extraction (MBTE) platform (NucliSENS® easyMAG®). A total of 60 pools of nasopharyngeal swab and 60 pools of posterior oropharyngeal saliva specimens, each consisting of 1 SARS-CoV-2 positive and 9 SARS-CoV-2 negative specimens, were included for the comparison. Real-time RT-PCR targeting the SARS-CoV-2 RdRp/Hel gene was performed, and GAPDH RT-PCR was used to detect RT-PCR inhibitors. No significant differences were observed in the Ct values and overall RT-PCR positive rates between LRE and MBTE platforms (92.5% (111/120] vs 90% (108/120]), but there was a slightly higher positive rate for LRE (88.3% (53/60]) than MBTE (81.7% (49/60]) among pooled saliva. The automated LRE method is comparable to a standard MBTE method for the detection of SAR-CoV-2 in pooled specimens, providing a suitable alternative automated extraction platform. Furthermore, LRE may be better suited for pooled saliva specimens due to more efficient removal of RT-PCR inhibitors.


Author(s):  
Aaron Topol ◽  
marlene.wolfe not provided ◽  
Krista Wigginton ◽  
Bradley White ◽  
Alexandria B Boehm

Please note that while this protocol is for TNA extraction using the Perkin Elmer Chemagic 360, RNA extraction with resuspended solids from this protocol has been verified to perform well using the Kingfisher MagMax kit as another high throughput, automated option and two manual Qiagen kits - the All Prep Powerviral DNA/RNA Kit and the Qiamp Viral RNA Mini Kit. This process instruction describes the steps for purification of nucleic acids from wastewater solids and preparation for downstream quantitative analysis with Reverse Transcriptase droplet digital Polymerase Chain Reaction (RT-ddPCR). Due to the large quantities of substances that have inhibitory effects on PCR in wastewater samples, a subsequent PCR inhibitor removal step is required after nucleic acid purification. Both steps of the process are carried out in a 96-well plate format. This method uses the resuspended solids generated using this protocol: High Throughput pre-analytical processing of wastewater settled solids for SARS-CoV-2 RNA analyses. RNA purification is carried out using a kit optimized for the purification of viral on for the Perkin Elmer Chemagic 360. Although only RNA is used in the downstream applications from this protocol, DNA is also eluted in this process. A crucial component of the purification kit are the magnetic particles coated with poly vinyl alcohol (M-PVA Magnetic Beads) which have a hydrophilic surface giving them an affinity for nucleic acids but not many other biological molecules. The workflow involves binding nucleic acids in a sample to the beads which are then transferred through a series of wash buffers to remove debris with a robotic head with magnetic rods. The OneStep PCR Inhibitor Removal Kits are PCR inhibitor clean up kits that contain all the components needed for efficient removal of contaminants that can inhibit downstream enzymatic reactions (e.g. PCR and RT) from DNA and RNA preparations. The column matrices in these PCR inhibitor clean up kits have been specifically designed for the efficient removal of polyphenolic compounds, humic/fulvic acids, tannins, melanin, etc. from the most impure DNA and RNA preparations. This process instruction applies to extraction of RNA from wastewater samples using the Chemagic™ Viral DNA/RNA 300 Kit H96 for the Perkin Elmer Chemagic 360 followed by PCR Inhibitor Removal with the Zymo OneStep-96 PCR Inhibitor Removal Kit.


Author(s):  
Weihua Yang ◽  
Xiaofei Dang ◽  
Qingxi Wang ◽  
Mingjie Xu ◽  
Qianqian Zhao ◽  
...  

AbstractCorona Virus Disease 2019 (COVID-19) is a recently emerged life-threatening disease caused by SARS-CoV-2. Real-time fluorescent PCR (RT-PCR) is the clinical standard for SARS-CoV-2 nucleic acid detection. To detect SARS-CoV-2 early and control the disease spreading on time, a faster and more convenient method for SARS-CoV-2 nucleic acid detecting, RT-LAMP method (reverse transcription loop-mediated isothermal amplification) was developed. RNA reverse transcription and nucleic acid amplification were performed in one step at 63 °C isothermal conditions, and the results can be obtained within 30 minutes. ORF1ab gene, E gene and N gene were detected at the same time. ORF1ab gene was very specific and N gene was very sensitivity, so they can guarantee both sensitivity and specificity for SARS-CoV-2. The sensitivity of RT-LAMP assay is similar to RT-PCR, and specificity was 99% as detecting 208 clinical specimens. The RT-LAMP assay reported here has the advantages of rapid amplification, simple operation, and easy detection, which is useful for the rapid and reliable clinical diagnosis of SARS-CoV-2.


RNA ◽  
2008 ◽  
Vol 14 (10) ◽  
pp. 1979-1990 ◽  
Author(s):  
S. M. Vasa ◽  
N. Guex ◽  
K. A. Wilkinson ◽  
K. M. Weeks ◽  
M. C. Giddings

Author(s):  
Hannah Wang ◽  
Jacob A. Miller ◽  
Michelle Verghese ◽  
Mamdouh Sibai ◽  
Daniel Solis ◽  
...  

ABSTRACTBackgroundEmergence of SARS-CoV-2 variants with concerning phenotypic mutations is of public health interest. Genomic surveillance is an important tool for pandemic response, but many laboratories do not have the resources to support population-level sequencing. We hypothesized that a spike genotyping nucleic acid amplification test (NAAT) could facilitate high-throughput variant surveillance.MethodsWe designed and analytically validated a one-step multiplex allele-specific reverse transcriptase polymerase chain reaction (RT-qPCR) to detect three non-synonymous spike protein mutations (L452R, E484K, N501Y). Assay specificity was validated with next-generation whole-genome sequencing. We then screened a large cohort of SARS-CoV-2 positive specimens from our San Francisco Bay Area population.ResultsBetween December 1, 2020 and March 1, 2021, we screened 4,049 unique infections by genotyping RT-qPCR, with an assay failure rate of 2.8%. We detected 1,567 L452R mutations (38.7%), 34 N501Y mutations (0.84%), 22 E484K mutations (0.54%), and 3 (0.07%) E484K+N501Y mutations. The assay had near-perfect (98-100%) concordance with whole-genome sequencing in a validation subset of 229 specimens, and detected B.1.1.7, B.1.351, B.1.427, B.1.429, B.1.526, and P.2 variants, among others. The assay revealed rapid emergence of L452R in our population, with a prevalence of 24.8% in December 2020 that increased to 62.5% in March 2021.ConclusionsWe developed and clinically implemented a genotyping RT-qPCR to conduct high-throughput SARS-CoV-2 variant screening. This approach can be adapted for emerging mutations and immediately implemented in laboratories already performing NAAT worldwide using existing equipment, personnel, and extracted nucleic acid.Summary / Key PointsEmergence of SARS-CoV-2 variants with concerning phenotypes is of public health interest. We developed a multiplex genotyping RT-qPCR to rapidly detect L452R, E484K, and N501Y with high sequencing concordance. This high-throughput alternative to resource-intensive sequencing enabled surveillance of L452R emergence.


Author(s):  
Soon Keong Wee ◽  
Suppiah Paramalingam Sivalingam ◽  
Eric Peng Huat Yap

There is an ongoing worldwide coronavirus disease 2019 (Covid-19) pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). At present, confirmatory diagnosis is by reverse transcription polymerase chain reaction (RT-PCR), typically taking several hours and requiring a molecular laboratory to perform. There is an urgent need for rapid, simplified and cost-effective detection methods. We have developed and analytically validated a protocol for direct rapid extraction-free PCR (DIRECT-PCR) detection of SARS-CoV-2 without the need for nucleic acid purification. As few as 6 RNA copies per reaction of viral nucleocapsid (N) gene from respiratory samples such as sputum and nasal exudate can be detected directly using our one-step inhibitor-resistant assay. The performance of this assay was validated on a commercially available portable PCR thermocycler. Viral lysis, reverse transcription, amplification and detection are achieved in a single-tube homogeneous reaction within 36 minutes. This minimized hands-on time, reduces turnaround-time for sample-to-result and obviates the need for RNA purification reagents. It could enable wider use of Covid-19 testing for diagnosis, screening and research in countries and regions where laboratory capabilities are limiting.


2020 ◽  
Vol 58 (8) ◽  
Author(s):  
Jonathan Hon-Kwan Chen ◽  
Cyril Chik-Yan Yip ◽  
Jasper Fuk-Woo Chan ◽  
Rosana Wing-Shan Poon ◽  
Kelvin Kai-Wang To ◽  
...  

ABSTRACT In December 2019, the coronavirus disease 2019 (COVID-19) pandemic caused by the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) was first reported in the Hubei province of China and later spread all over the world. There was an urgent need of a high-throughput molecular test for screening the COVID-19 patients in the community. The Luminex NxTAG CoV extended panel is a high-throughput FDA emergency use-authorized molecular diagnostic assay for SARS-CoV-2 detection. This system targets three genes (ORF1ab, N, and E genes) of SARS-CoV-2, the ORF1ab region of SARS-CoV, and the ORF5 region of MERS-CoV. In this study, we evaluated the diagnostic performance of this system with nasopharyngeal swab specimens of 214 suspected COVID-19 patients in Hong Kong. The results were compared with our routine COVID-19 reverse transcription-PCR (RT-PCR) protocol with a LightMix SarbecoV E-gene kit and an in-house RdRp/Hel RT-PCR assay. The NxTAG CoV extended panel demonstrated 97.8% sensitivity and 100% specificity to SARS-CoV-2 in nasopharyngeal specimens. On low-viral load specimens, the sensitivity of the NxTAG panel could still maintain at 85.71%. Strong agreement was observed between the NxTAG panel and the routine COVID-19 RT-PCR protocol (kappa value = 0.98). Overall, the E gene target of the NxTAG panel demonstrated the highest sensitivity among the three SARS-CoV-2 targets, while the N gene targets demonstrated the least. In conclusion, the NxTAG CoV extended panel is simple to use, and it has high diagnostic sensitivity and specificity to SARS-CoV-2 in nasopharyngeal specimens. We recommend this diagnostic system for high-throughput COVID-19 screening in the community.


protocols.io ◽  
2021 ◽  
Author(s):  
Aaron Topol ◽  
marlene.wolfe not provided ◽  
Krista Wigginton ◽  
Bradley White ◽  
Alexandria B

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