scholarly journals Machine learning detects SARS-CoV-2 and variants rapidly on DNA aptamer metasurfaces

2021 ◽  
Author(s):  
Hulya Torun ◽  
Buse Bilgin ◽  
Muslum Ilgu ◽  
Cenk Yanik ◽  
Sukru Numan Batur ◽  
...  
Keyword(s):  
Machine Learning ◽  
Dna Aptamer ◽  
Clinical Samples ◽  
Rt Pcr ◽  
Preventive Screening ◽  
Nasal Swabs ◽  
Screening And Identification ◽  
Direct Sensing ◽  
Virus Interaction ◽  
Polymerase Chain

COVID-19 is detected using reverse transcription polymerase chain reaction (RT-PCR) of nasal swabs. A very sensitive and rapid detection technique using easily-collected fluids like saliva must be developed for safe and precise mass testing. Here, we introduce a metasurface platform for direct sensing of COVID-19 from unprocessed saliva. We computationally screen gold metasurfaces out of a pattern space of 2100 combinations for strongly-enhanced light-virus interaction with machine learning and use it to investigate the presence and concentration of the SARS-CoV-2. We use machine learning to identify the virus from Raman spectra with 95.2% sensitivity and specificity on 36 PCR positive and 33 negative clinical samples and to distinguish wild-type, alpha, and beta variants. Our results could pave the way for effective, safe and quantitative preventive screening and identification of variants.

scholarly journals Machine Learning Prediction of SARS-CoV-2 Polymerase Chain Reaction Results with Routine Blood Tests

2020 ◽  
Author(s):  
Thomas Tschoellitsch ◽  
Martin Dünser ◽  
Carl Böck ◽  
Karin Schwarzbauer ◽  
Jens Meier
Keyword(s):  
Machine Learning ◽  
Polymerase Chain Reaction ◽  
Characteristic Curve ◽  
Cohort Analysis ◽  
Rt Pcr ◽  
Chain Reaction ◽  
Blood Tests ◽  
Routine Blood ◽  
Machine Learning Model ◽  
Polymerase Chain

Abstract Objective The diagnosis of COVID-19 is based on the detection of SARS-CoV-2 in respiratory secretions, blood, or stool. Currently, reverse transcription polymerase chain reaction (RT-PCR) is the most commonly used method to test for SARS-CoV-2. Methods In this retrospective cohort analysis, we evaluated whether machine learning could exclude SARS-CoV-2 infection using routinely available laboratory values. A Random Forests algorithm with 1353 unique features was trained to predict the RT-PCR results. Results Out of 12,848 patients undergoing SARS-CoV-2 testing, routine blood tests were simultaneously performed in 1528 patients. The machine learning model could predict SARS-CoV-2 test results with an accuracy of 86% and an area under the receiver operating characteristic curve of 0.90. Conclusion Machine learning methods can reliably predict a negative SARS-CoV-2 RT-PCR test result using standard blood tests.

scholarly journals Inactivation of SARS-CoV-2 virus in saliva using a guanidium based transport medium suitable for RT-PCR diagnostic assays

PLoS ONE ◽  
2021 ◽  
Vol 16 (6) ◽  
pp. e0252687
Author(s):  
Sukalyani Banik ◽  
Kaheerman Saibire ◽  
Shraddha Suryavanshi ◽  
Glenn Johns ◽  
Soumitesh Chakravorty ◽  
...  
Keyword(s):  
Limit Of Detection ◽  
Viral Rna ◽  
Clinical Samples ◽  
Sample Collection ◽  
Rt Pcr ◽  
Diagnostic Assays ◽  
Guanidinium Thiocyanate ◽  
Upper Respiratory ◽  
Polymerase Chain ◽  
The Stability

Background Upper respiratory samples used to test for SARS-CoV-2 virus may be infectious and present a hazard during transport and testing. A buffer with the ability to inactivate SARS-CoV-2 at the time of sample collection could simplify and expand testing for COVID-19 to non-conventional settings. Methods We evaluated a guanidium thiocyanate-based buffer, eNAT™ (Copan) as a possible transport and inactivation medium for downstream Reverse Transcriptase-Polymerase Chain Reaction (RT-PCR) testing to detect SARS-CoV-2. Inactivation of SARS-CoV-2 USA-WA1/2020 in eNAT and in diluted saliva was studied at different incubation times. The stability of viral RNA in eNAT was also evaluated for up to 7 days at room temperature (28°C), refrigerated conditions (4°C) and at 35°C. Results SARS-COV-2 virus spiked directly in eNAT could be inactivated at >5.6 log10 PFU/ml within a minute of incubation. When saliva was diluted 1:1 in eNAT, no cytopathic effect (CPE) on VeroE6 cells was observed, although SARS-CoV-2 RNA could be detected even after 30 min incubation and after two cell culture passages. A 1:2 (saliva:eNAT) dilution abrogated both CPE and detectable viral RNA after as little as 5 min incubation in eNAT. SARS-CoV-2 RNA from virus spiked at 5X the limit of detection remained positive up to 7 days of incubation in all tested conditions. Conclusion eNAT and similar guanidinium thiocyanate-based media may be of value for transport, stabilization, and processing of clinical samples for RT-PCR based SARS-CoV-2 detection.

scholarly journals Evaluation of sample collection and transport strategies to enhance yield, accessibility, and biosafety of COVID-19 RT-PCR testing

2021 ◽  
Author(s):  
Padmapriya Banada ◽  
David Elson ◽  
Naranjargal Daivaa ◽  
Claire Park ◽  
Samuel Desind ◽  
...  
Keyword(s):  
Sampling Methods ◽  
Diagnostic Yield ◽  
Sampling Strategy ◽  
Sample Collection ◽  
Rt Pcr ◽  
Viral Inactivation ◽  
Viral Transport ◽  
Nasal Swabs ◽  
Polymerase Chain ◽  
Transport Buffer

ABSTRACTSensitive, accessible, and biosafe sampling methods for COVID-19 reverse-transcriptase polymerase chain reaction (RT-PCR) assays are needed for frequent and widespread testing. We systematically evaluated diagnostic yield across different sample collection and transport workflows, including the incorporation of a viral inactivation buffer. We prospectively collected nasal swabs, oral swabs, and saliva, from 52 COVID-19 RT-PCR-confirmed patients, and nasopharyngeal (NP) swabs from 37 patients. Nasal and oral swabs were placed in both viral transport media (VTM) and eNAT™, a sterilizing transport buffer, prior to testing with the Xpert Xpress SARS-CoV-2 (Xpert) test. The sensitivity of each sampling strategy was compared using a composite positive standard. Overall, swab specimens collected in eNAT showed superior sensitivity compared to swabs in VTM (70% vs 57%, P=0.0022). Direct saliva 90.5%, (95% CI: 82%, 95%), followed by NP swabs in VTM and saliva in eNAT, was significantly more sensitive than nasal swabs in VTM (50%, P<0.001) or eNAT (67.8%, P=0.0012) and oral swabs in VTM (50%, P<0.0001) or eNAT (56%, P<0.0001). Saliva and use of eNAT buffer each increased detection of SARS-CoV-2 with the Xpert test; however, no single sample matrix identified all positive cases.

scholarly journals Systematic Review and Meta-analysis of Real-time Polymerase Chain Reaction assay for the detection of COVID-19 from clinical samples in low-and middle-income countries: Protocol

2021 ◽  
Author(s):  
Emmanuel Oladipo Babafemi
Keyword(s):  
Systematic Review ◽  
Polymerase Chain Reaction ◽  
Real Time ◽  
Meta Analysis ◽  
Clinical Samples ◽  
Rt Pcr ◽  
Chain Reaction ◽  
Pcr Assay ◽  
Middle Income ◽  
Polymerase Chain

Abstract Background: COVID-19 has spread globally since its discovery in Hubei province, China in December 2019 and became pandemic in 2020. COVID-19 is a new betacoronavirus and a variant of severe acute respiratory syndrome coronavirus 2 (SARA- CoV-2). Rapid, accurate and reliable diagnosis of COVID-19 will prevent the spread and allow for appropriate management. The main objective of this systematic review is to identify, appraise and summarise the published evidence on the diagnostic performance and effectiveness of SARS-CoV-2 virus in the diagnosis of current or previous COVID-19 using real-time polymerase chain reaction (RT-PCR) assay in low-and middle-income countries (LMICs). Methods: We will search MEDLINE/PubMed, EMBASE, BIOSIS, LILACS, Cochrane Infectious Diseases Group Specialised Register (CIDG SR), Global Health, and CINAHL for published studies for the diagnosis of COVID-19 using real-time polymerase chain reaction assay in LMICs There will be no restriction regarding the language, date of publication, and publication status. We will include retrospective, cross-sectional and cohort observational studies will be included in the review. Selection of studies, data extraction and management, assessment of risk of bias, and quality of evidence will be performed by two independent reviewers (EB and BC). A third researcher (GM) will be consulted in case of discrepancies. Depending on the availability and quality of the data, a meta-analysis will be performed. Otherwise, findings will be qualitatively reported. Discussion: To our knowledge, this is the first systematic review and meta-analysis to assess the uptake of RT-PCR assay for SARS-CoV-2 detection from clinical samples in human in LMICs. This review will make available evidence on the uptake, accuracy, approach, and interpretation of results of this assay in the context of COVID-19 diagnosis which will meet an urgent need, considering the diagnostic challenges of RT-PCR assay for COVID-19 diagnosis in humans. Systematic review registration: PROSPERO CRD42021271894

scholarly journals Impact of false negative results of RT-PCR test for SARS-CoV-2 in COVID-19 case count as applied to Mexico

2020 ◽  
Author(s):  
Isaac J. Núñez ◽  
Pablo F. Belaunzarán-Zamudio ◽  
Yanink Caro-Vega
Keyword(s):  
False Negative ◽  
Open Data ◽  
Clinical Samples ◽  
Rt Pcr ◽  
Negative Results ◽  
Case Count ◽  
False Negative Results ◽  
True Number ◽  
High Prevalence ◽  
Polymerase Chain

Underestimation of the number of cases during the COVID-19 pandemic has been a constant concern worldwide. Case confirmation is based on identification of SARS-CoV-2 RNA using real time polymerase chain reaction (RT-PCR) in clinical samples. However, these tests have suboptimal sensitivity, especially during the early and late course of infection. Using open data, we estimated that among 1 343 730 people tested in Mexico since February 27th, there were 838 377 (95% CL 734 605 - 1 057 164) cases, compared with 604 376 considering only positive tests. ICU admissions and deaths were around 16% and 9% higher than reported. Thus, we show that accounting for the sensitivity of SARS-Cov-2 RT-PCR diagnostic tests is a simple way to improve estimations for the true number of COVID-19 cases in tested people, particularly in high-prevalence populations. This could aid to better inform public health measures and reopening policies.

scholarly journals Effect of various decontamination procedures on disposable N95 mask integrity and SARS-CoV-2 infectivity

2020 ◽  
pp. 1-5 ◽  
Author(s):  
Jeffrey S. Smith ◽  
Haley Hanseler ◽  
John Welle ◽  
Rogan Rattray ◽  
Mary Campbell ◽  
...  
Keyword(s):  
Clinical Samples ◽  
Rt Pcr ◽  
Cell Infection ◽  
High Demand ◽  
Industrial Grade ◽  
Fit Testing ◽  
Virucidal Effect ◽  
Polymerase Chain ◽  
Evidenced Based ◽  
Infectious Potential

Abstract Introduction: The COVID-19 pandemic has created a high demand on personal protective equipment, including disposable N95 masks. Given the need for mask reuse, we tested the feasibility of vaporized hydrogen peroxide (VHP), ultraviolet light (UV), and ethanol decontamination strategies on N95 mask integrity and the ability to remove the infectious potential of SARS-CoV-2. Methods: Disposable N95 masks, including medical grade (1860, 1870+) and industrial grade (8511) masks, were treated by VHP, UV, and ethanol decontamination. Mask degradation was tested using a quantitative respirator fit testing. Pooled clinical samples of SARS-CoV-2 were applied to mask samples, treated, and then either sent immediately for real-time reverse transcriptase–polymerase chain reaction (RT-PCR) or incubated with Vero E6 cells to assess for virucidal effect. Results: Both ethanol and UV decontamination showed functional degradation to different degrees while VHP treatment showed no significant change after two treatments. We also report a single SARS-CoV-2 virucidal experiment using Vero E6 cell infection in which only ethanol treatment eliminated detectable SARS-CoV-2 RNA. Conclusions: We hope our data will guide further research for evidenced-based decisions for disposable N95 mask reuse and help protect caregivers from SARS-CoV-2 and other pathogens.

DETECTION OF RESPIRATORY SYNCITIAL VIRUS (RSV) IN LOWER ACUTE RESPIRATORY INFECTIONS BY NESTED REVERSE TRANSCRIPTION- POLYMERASE CHAIN REACTION

2011 ◽  
pp. 11-15
Author(s):  
Keyword(s):  
Polymerase Chain Reaction ◽  
Reverse Transcription ◽  
Respiratory Infections ◽  
Clinical Samples ◽  
Acute Respiratory Infections ◽  
Rt Pcr ◽  
Minimal Level ◽  
Chain Reaction ◽  
Pcr Assay ◽  
Polymerase Chain

Objective: To develop and apply a nested reverse transcription- polymerase chain reaction (nested RT-PCR) for detection of RSV in lower acute respiratory infections. Materials and methods: A nested reverse transcription- polymerase chain reaction was used to amplify a sequence of the F gene in the RSV genomic RNA, optimized and compared the sensitivity and specificity of this assay with the control samples and then applied this procedure for diagnosing RSV from clinical samples. Results: This nested RT-PCR assay amplified the specific target fragment of RSV RNA and did not amplify any sequence of genomes of the tested common viruses and bacteria causing respiratory infections. The minimal level of detection of this procedure was 102 copies/ml. Results for detection of RSV on 109 samples of throat swabs or nasopharyngeal swabs from children with lower respiratory infections showed that twenty seven patients were positive with RSV ( 24.8%), among which six out of 30 (20%) were with bronchitis, seven out of 26 ( 27%) were with bronchiolitis and fourteen out of 53 (26.4%) were with pneumonia. Conclusion: This nested RT-PCR was found to be useful and reliable for detection of RSV in respiratory infections.

scholarly journals Detection of Bluetongue Virus Serogroup by Polymerase Chain Reaction

1992 ◽  
Vol 4 (4) ◽  
pp. 400-405 ◽  
Author(s):  
Geoffrey Y. Akita ◽  
Jarasvech Chinsangaram ◽  
Bennie I. Osburn ◽  
Marius Ianconescu ◽  
Rozalia Kaufman
Keyword(s):  
Polymerase Chain Reaction ◽  
Bluetongue Virus ◽  
Wide Spectrum ◽  
Genome Segment ◽  
Clinical Samples ◽  
Rt Pcr ◽  
Chain Reaction ◽  
Field Isolates ◽  
Viral Particles ◽  
Polymerase Chain

To facilitate detection of active bluetongue virus (BTV) infection, a polymerase chain reaction (PCR) protocol was developed. The BTV reverse transcriptase PCR (RT-PCR) is a 1-tube reaction and involves chemical denaturation of the double-stranded viral RNA target, a complementary DNA (cDNA) synthesis step, and PCR amplification of the cDNA. BTV RT-PCR using primers derived from highly conserved genome segment 10 results in a 251–base pair (bp) product. BTV RNA from all USA prototype serotypes 2, 10, 11, 13, and 17; a wide spectrum of USA BTV field isolates including serotypes 10, 11, 13, and 17; and a spectrum of Israeli field isolates including serotypes 2, 4, 6, 10, and 16 were detected by BTV RT-PCR. With agarose gels, the 251–bp product was detected from as little as 100 fg-1 pg of BTV RNA, which is equivalent to 5 × 103-5 × 104 viral particles or 5 × 102-5 × 103 infectious units. With dot blot hybridization, specific PCR product was detected from as little as 1 fg of BTV RNA, which is equivalent to 50 viral particles, or 5 infectious units. This level of sensitivity is comparable to that of virus isolation. The BTV RT-PCR using primers derived from genome segment 10 can detect a wide spectrum of USA and Israeli BTV serotypes and has potential for detection of infection by the BTV serogroup. Application of this BTV PCR to clinical samples is in progress.

Detection of blaVIM and blaIMP Carbapenemase-Producing Pseudomonas aeruginosa from Clinical Samples in Iran

2021 ◽  
Author(s):  
Mohammad Reza Zolfaghari
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Cross Sectional Study ◽  
Clinical Samples ◽  
Sectional Study ◽  
Rt Pcr ◽  
Chain Reaction ◽  
Cross Sectional ◽  
High Prevalence ◽  
Polymerase Chain ◽  
High Level

Background and Aims: The prevalence of carbapenemase-producing Pseudomonas aeruginosa (P. aeruginosa) strains has been recently reported worldwide. Therefore, accurate and rapid detection of carbapenemase-producing isolates is essential. So, this study aimed to detect blaVIM and blaIMP carbapenemase-producing strains using the modified Hodge test (MHT) and reverse transcription-polymerase chain reaction (RT-PCR). Materials and Methods: In this cross-sectional study, P. aeruginosa  strains were collected from clinical samples (blood, urine, wound, and other liquids body) in Firoozgar and Shahid Motahari Hospitals in Tehran and Velayat Hospital in Rasht Province, from May to December 2018. After identifying the isolates using the standard microbial tests, carbapenemase-producing strains were isolated by the modified hodge test. After that, the detection of blaVIM and blaIMP genes was performed by RT-PCR technique. Results: One hundred P. aeruginosa were isolated from different clinical samples. Among these, 74 (74%) isolates were considered as carbapenemase positive using MHT. The frequencies of blaVIM and blaIMP genes were obtained as 83% and 11%, respectively. Conclusions: The results of this study indicate a high level of resistance to most of the antibiotics tested and a high prevalence of blaVIM gene in P. aeruginosa strains.

scholarly journals Detection of Bovine Torovirus and other Enteric Pathogens in Feces from Diarrhea Cases in Cattle

2003 ◽  
Vol 15 (3) ◽  
pp. 205-212 ◽  
Author(s):  
Armando E. Hoet ◽  
Paul R. Nielsen ◽  
Mustafa Hasoksuz ◽  
Christopher Thomas ◽  
Thomas E. Wittum ◽  
...  
Keyword(s):  
Etiologic Agent ◽  
Enteric Pathogens ◽  
Clinical Samples ◽  
Enzyme Linked Immunosorbent Assay ◽  
Rt Pcr ◽  
Pcr Assay ◽  
Salmonella Spp ◽  
Diagnostic Laboratory ◽  
Fecal Samples ◽  
Polymerase Chain

The objectives of this study were to determine the prevalence of bovine torovirus (BoTV) in bovine fecal samples from diarrhea cases submitted to the Ohio Animal Disease Diagnostic Laboratory (ADDL) and to assess if a relationship exists between BoTV and the other enteric pathogens detected. From November 1999 to May 2001, 259 specimens from 53 calves (≤6 months old), 27 young adults (≤2 years), 125 adults (≥2 years), and 54 animals of unknown age were examined by an antigen-capture enzyme-linked immunosorbent assay (ELISA) and reverse transcriptase-polymerase chain reaction (RT-PCR) assay developed to detect BoTV Testing for other enteric pathogens was performed by ADDL, and the results were analyzed with the BoTV data. The BoTV was detected using ELISA or RT-PCR in 9.7% (25/259) of the clinical samples, 56% (14/25) of which were from calves ( P < 0.001) representing 26.4% (14/53) of the calves tested. Of the BoTV-positive calves, 71% (10/14) were less than 3 weeks of age. In 11/25 positive specimens, BoTV was the only pathogen detected among those examined. Other enteric organisms detected alone or in combination with BoTV in calf samples were rotavirus, coronavirus, Salmonella spp., Cryptosporidium spp., and Giardia spp.; but no consistent association between BoTV and these organisms was observed. In summary, BoTV was detected in fecal samples from cattle with diarrhea, principally in young calves less than 3 weeks of age. Future studies of infectious diarrhea in cattle should also include assays for this etiologic agent.

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