scholarly journals Assessment of the use and quick preparation of saliva for rapid microbiological diagnosis of COVID-19

2020 ◽  
Author(s):  
Mariana Fernández-Pittol ◽  
Juan Carlos Hurtado ◽  
Estela Moreno-García ◽  
Elisa Rubio ◽  
Mireia Navarro ◽  
...  
Keyword(s):  
Real Time ◽  
Rna Extraction ◽  
Rna Isolation ◽  
Heat Inactivation ◽  
Rt Pcr ◽  
Elution Volume ◽  
Heated Sample ◽  
Predictive Values ◽  
One Step ◽  
Sensitivity Specificity

AbstractThe objective of this study was to assess the performance of direct real time RT-PCR detection of SARS-CoV-2 in heated saliva samples, avoiding the RNA isolation step. Oropharyngeal and nasopharyngeal swabs together with saliva samples were obtained from 51 patients clinically diagnosed as potentially having COVID-19. Two different methods were compared: 1. RNA was extracted from 500 μl of sample using a MagNA Pure Compact Instrument with an elution volume of 50μl and 2. 700µL of saliva were heat-inactivated at 96°C for 15 minutes, and directly subjected to RT-PCR. One step real time RT-PCR was performed using 5 μl of extracted RNA or directly from 5 μl of heated sample. RT-PCR was performed targeting the SARS-CoV-2 envelope (E) gene region. Diagnostic performance was assessed using the results of the RT-PCR from nasopharyngeal and oropharyngeal swabs as the gold standard. The overall sensitivity, specificity, positive and negative predictive values were 81.08%, 92.86%, 96.77% and 65.00%, respectively when RNA extraction was included in the protocol with saliva, whereas sensitivity, specificity, positive and negative predictive values were 83.78%, 92.86%, 68.42% and 96.88%, respectively, for the heat-inactivation protocol. However, when the analysis was performed exclusively on saliva samples with a limited time from the onset of symptoms (<9 days, N=28), these values were 90%, 87.5%, 44% and 98.75% for the heat-inactivation protocol. The study showed that RT-PCR can be performed using saliva in an RNA extraction free protocol, showing good sensitivity and specificity.

scholarly journals Isolation and Detection of Enterovirus RNA from Large-Volume Water Samples by Using the NucliSens miniMAG System and Real-Time Nucleic Acid Sequence-Based Amplification

2005 ◽  
Vol 71 (7) ◽  
pp. 3734-3740 ◽  
Author(s):  
Saskia A. Rutjes ◽  
Ronald Italiaander ◽  
Harold H. J. L. van den Berg ◽  
Willemijn J. Lodder ◽  
Ana Maria de Roda Husman
Keyword(s):  
Nucleic Acid ◽  
Real Time ◽  
Large Volume ◽  
Water Samples ◽  
Extraction Method ◽  
Rna Extraction ◽  
Rna Isolation ◽  
Rt Pcr ◽  
Virus Rna ◽  
Nasba Assay

ABSTRACT Concentration of water samples is a prerequisite for the detection of the low virus levels that are present in water and may present a public health hazard. The aim of this study was to develop a rapid, standardized molecular method for the detection of enteroviruses in large-volume surface water samples, using a concentration method suitable for the detection of infectious viruses as well as virus RNA. Concentration of water was achieved by a conventional filter adsorption-elution method and ultrafiltration, resulting in a 10,000-fold concentration of the sample. Isolation of virus RNA by a silica-based RNA extraction method was compared with the nonmagnetic and magnetic NucliSens RNA isolation methods. By using the silica-based RNA extraction method in two out of five samples, enterovirus RNA was detected, whereas four out of five samples were positive following RNA isolation with magnetic silica beads. Moreover, estimated RNA levels increased at least 100 to 500 times. Furthermore, we compared enterovirus detection by an in-house reverse transcription (RT)-PCR with a novel commercially available real-time nucleic acid sequence-based amplification (NASBA) assay. We found that the rapid real-time NASBA assay was slightly less sensitive than our in-house RT-PCR. The advantages, however, of a commercial real-time NASBA assay, like the presence of an internal control RNA, standardization, and enormous decrease in turnaround time, makes it an attractive alternative to RT-PCR.

A one-step multiplex real-time RT-PCR assay for rapid and simultaneous detection of human norovirus genogroup I, II and IV

2013 ◽  
Vol 189 (2) ◽  
pp. 277-282 ◽  
Author(s):  
Yong Yan ◽  
Heng-hui Wang ◽  
Lei Gao ◽  
Ji-mei Ji ◽  
Zhi-jie Ge ◽  
...  
Keyword(s):  
Real Time ◽  
Simultaneous Detection ◽  
Rt Pcr ◽  
Pcr Assay ◽  
Human Norovirus ◽  
One Step

Development of a one step real-time RT-PCR method for sensitive detection of human astrovirus

2006 ◽  
Vol 133 (1) ◽  
pp. 14-19 ◽  
Author(s):  
Enrique Royuela ◽  
Ana Negredo ◽  
Alicia Sánchez-Fauquier
Keyword(s):  
Real Time ◽  
Sensitive Detection ◽  
Rt Pcr ◽  
One Step ◽  
Human Astrovirus ◽  
Pcr Method

Clinical diagnosis of early dengue infection by novel one-step multiplex real-time RT-PCR targeting NS1 gene

2015 ◽  
Vol 65 ◽  
pp. 11-19 ◽  
Author(s):  
Je-Hyoung Kim ◽  
Chom-Kyu Chong ◽  
Mangalam Sinniah ◽  
Jeyaindran Sinnadurai ◽  
Hyun-Ok Song ◽  
...  
Keyword(s):  
Real Time ◽  
Clinical Diagnosis ◽  
Dengue Infection ◽  
Rt Pcr ◽  
One Step ◽  
Ns1 Gene ◽  
Pcr Targeting

Rapid and quantitative detection of mumps virus RNA by one-step real-time RT-PCR

2004 ◽  
Vol 49 (2) ◽  
pp. 83-88 ◽  
Author(s):  
Ayhan Kubar ◽  
Mehmet Yapar ◽  
Bulent Besirbellioglu ◽  
I.Yasar Avci ◽  
Cakır Guney
Keyword(s):  
Real Time ◽  
Mumps Virus ◽  
Quantitative Detection ◽  
Rt Pcr ◽  
Virus Rna ◽  
One Step

scholarly journals Direct Viral RNA Detection of SARS-CoV-2 and DENV in Inactivated Samples by Real-Time RT-qPCR: Implications for Diagnosis in Resource Limited Settings with Flavivirus Co-Circulation

Pathogens ◽  
2021 ◽  
Vol 10 (12) ◽  
pp. 1558
Author(s):  
Zhan Qiu Mao ◽  
Mizuki Fukuta ◽  
Jean Claude Balingit ◽  
Thi Thanh Ngan Nguyen ◽  
Co Thach Nguyen ◽  
...  
Keyword(s):  
Real Time ◽  
Early Stage ◽  
Rna Extraction ◽  
Viral Rna ◽  
Clinical Samples ◽  
Heat Inactivation ◽  
Resource Limited Settings ◽  
Rna Detection ◽  
Resource Limited ◽  
Starting Point

The RT-qPCR method remains the gold standard and first-line diagnostic method for the detection of SARS-CoV-2 and flaviviruses, especially in the early stage of viral infection. Rapid and accurate viral detection is a starting point in the containment of the COVID-19 pandemic and flavivirus outbreaks. However, the shortage of diagnostic reagents and supplies, especially in resource-limited countries that experience co-circulation of SARS-CoV-2 and flaviviruses, are limitations that may result in lesser availability of RT-qPCR-based diagnostic tests. In this study, the utility of RNA-free extraction methods was assessed for the direct detection of SARS-CoV-2 and DENV-2 in heat-inactivated or chemical-inactivated samples. The findings demonstrate that direct real-time RT-qPCR is a feasible option in comparison to conventional real-time RT-qPCR based on viral genome extraction-based methods. The utility of heat-inactivation and direct real-time RT-qPCR for SARS-CoV-2, DENV-2 viral RNA detection was demonstrated by using clinical samples of SARS-CoV-2 and DENV-2 and spiked cell culture samples of SARS-CoV-2 and DENV-2. This study provides a simple alternative workflow for flavivirus and SARS-CoV-2 detection that includes heat inactivation and viral RNA extraction-free protocols, with aims to reduce the risk of exposure during processing of SARS-CoV-2 biological specimens and to overcome the supply-chain bottleneck, particularly in resource limited settings with flavivirus co-circulation.

scholarly journals Direct-RT-qPCR Detection of SARS-CoV-2 without RNA Extraction as Part of a COVID-19 Testing Strategy: From Sample to Result in One Hour

Diagnostics ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 605 ◽  
Author(s):  
Eva Kriegova ◽  
Regina Fillerova ◽  
Petr Kvapil
Keyword(s):  
High Throughput Screening ◽  
High Speed ◽  
Limit Of Detection ◽  
Point Of Care ◽  
Rna Extraction ◽  
Rna Isolation ◽  
High Sensitivity ◽  
Ease Of Use ◽  
Diagnostic Tools ◽  
Heat Inactivation

Due to the lack of protective immunity in the general population and the absence of effective antivirals and vaccines, the Coronavirus disease 2019 (COVID-19) pandemic continues in some countries, with local epicentres emerging in others. Due to the great demand for effective COVID-19 testing programmes to control the spread of the disease, we have suggested such a testing programme that includes a rapid RT-qPCR approach without RNA extraction. The Direct-One-Step-RT-qPCR (DIOS-RT-qPCR) assay detects severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in less than one hour while maintaining the high sensitivity and specificity required of diagnostic tools. This optimised protocol allows for the direct use of swab transfer media (14 μL) without the need for RNA extraction, achieving comparable sensitivity to the standard method that requires the time-consuming and costly step of RNA isolation. The limit of detection for DIOS-RT-qPCR was lower than seven copies/reaction, which translates to 550 virus copies/mL of swab. The speed, ease of use and low price of this assay make it suitable for high-throughput screening programmes. The use of fast enzymes allows RT-qPCR to be performed under standard laboratory conditions within one hour, making it a potential point-of-care solution on high-speed cycling instruments. This protocol also implements the heat inactivation of SARS-CoV-2 (75 °C for 10 min), which renders samples non-infectious, enabling testing in BSL-2 facilities. Moreover, we discuss the critical steps involved in developing tests for the rapid detection of COVID-19. Implementing rapid, easy, cost-effective methods can help control the worldwide spread of the COVID-19 infection.

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