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1.
Clin Chim Acta ; 557: 117864, 2024 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-38461865

RESUMO

BACKGROUND AND AIMS: A pilot external quality assessment (EQA) scheme for molecular detection of Ureaplasma urealyticum (UU) was conducted by the National Center for Clinical Laboratories (NCCL) to evaluate the testing capabilities of clinical laboratories and the actual performance of DNA-based nucleic acid amplification tests (NAAT) and RNA-based NAATs when applied in clinical settings. MATERIALS AND METHODS: The EQA panel contained twelve lyophilized samples, including positive samples containing inactivated cell culture supernatants of UU at different concentrations and sterile saline for negative samples. The positive samples were further divided into three groups of high, moderate and low concentrations. The panels were distributed to the participants and the datasets were analyzed according to the qualitative results. RESULTS: A total of 365 laboratories participated in the EQA scheme, and 360 results submitted by 338 laboratories were collected, of which 96.11 % (346/360) of the returned results and 95.86 % (324/338) of the laboratories were deemed competent. The positive percentage agreement (PPA) was ≥ 97.5 % for high and moderate concentration samples, but varied significantly for low concentration samples, decreasing from 86.94 % to 51.94 % as the sample concentration decreased. Additionally, for low concentration samples, RNA-based NAAT showed higher PPAs than DNA-based NAATs, but these results were specific to UU supernatants used in this study. CONCLUSION: Most of UU detection assays employed by the participants were generally consistent with their estimated limit of detection (LOD), and the majority of participants can reliably detect UU samples with high and moderate concentrations, while the poor analytical performance for low concentration samples requires further improvement and optimization.


Assuntos
Técnicas de Amplificação de Ácido Nucleico , Ureaplasma urealyticum , Humanos , Ureaplasma urealyticum/genética , Técnicas de Amplificação de Ácido Nucleico/métodos , Laboratórios , RNA , DNA , China
2.
PLoS One ; 19(2): e0298087, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38335219

RESUMO

Malaria eradication efforts in resource-limited areas require a rapid, economical, and accurate tool for detecting of the low parasitemia. The malaria rapid diagnostic test (mRDT) is the most suitable for on-site detection of the deadliest form of malaria, Plasmodium falciparum. However, the deletions of histidine rich protein 2 and 3 genes are known to compromise the effectiveness of mRDT. One of the approaches that have been explored intensively for on-site diagnostics is the loop-mediated isothermal amplification (LAMP). LAMP is a one-step amplification that allows the detection of Plasmodium species in less than an hour. Thus, this study aims to present a new primer set to enhance the performance of a colorimetric LAMP (cLAMP) for field application. The primer binding regions were selected within the A-type of P. falciparum 18S rRNA genes, which presents a dual gene locus in the genome. The test result of the newly designed primer indicates that the optimal reaction condition for cLAMP was 30 minutes incubation at 65°C, a shorter incubation time compared to previous LAMP detection methods that typically takes 45 to 60 minutes. The limit of detection (LoD) for the cLAMP using our designed primers and laboratory-grown P. falciparum (3D7) was estimated to be 0.21 parasites/µL which was 1,000-fold higher than referencing primers. Under optimal reaction condition, the new primer sets showed the sensitivity (100%, 95% CI: 80.49-100%) and specificity (100%, 95% CI: 94.64-100%) with 100% (95% CI: 95.70-100%) accuracy on the detection of dried blood spots from Malawi (n = 84). Briefly, the newly designed primer set for P. falciparum detection exhibited high sensitivity and specificity compared to referenced primers. One great advantage of this tool is its ability to be detected by the naked eye, enhancing field approaches. Thus, this tool has the potential to be effective for accurate early parasite detection in resource-limited endemic areas.


Assuntos
Malária Falciparum , Malária , Humanos , Plasmodium falciparum/genética , Colorimetria , Sensibilidade e Especificidade , Malária/parasitologia , Malária Falciparum/diagnóstico , Malária Falciparum/parasitologia , Técnicas de Amplificação de Ácido Nucleico/métodos , Técnicas de Diagnóstico Molecular/métodos
3.
Diagn Microbiol Infect Dis ; 108(2): 116111, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38016385

RESUMO

The diagnosis of Chikungunya (CHIKV), along with the simultaneous monitoring of virus circulation in the population or vectors, is essential for global health. Although effective diagnostic methods for CHIKV, such as RT-qPCR, exist, their utilization is constrained by high costs. With the aim of contributing to the field of diagnostics, we have developed a diagnostic assay using isothermal amplification technology with visually interpretable results. This test can detect the virus within a maximum timeframe of 30 minutes. The detection limit of RT-LAMP CHIKV was found to be 66 copies of RNA molecules (Ct ≅ 31.28), and no cross-reactivity with other arboviruses was observed. During test validation, our assay demonstrated a sensitivity of 80.43%, specificity of 100%, and an overall accuracy of 88.89%. By utilizing more cost-effective reagents and equipment compared to RT-qPCR, this test holds the potential for broader application and enhanced accessibility, particularly in point-of-care settings.


Assuntos
Febre de Chikungunya , Vírus Chikungunya , Humanos , Febre de Chikungunya/diagnóstico , Análise Custo-Benefício , Sensibilidade e Especificidade , Técnicas de Diagnóstico Molecular/métodos , Vírus Chikungunya/genética , Sistemas Automatizados de Assistência Junto ao Leito , Técnicas de Amplificação de Ácido Nucleico/métodos , RNA Viral/genética , RNA Viral/análise
4.
Biotechniques ; 76(3): 114-118, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38131320

RESUMO

A colorimetric loop-mediated isothermal amplification assay detects changes in pH during amplification based on color changes at a constant temperature. Currently, various studies have focused on developing and assessing molecular point-of-care testing instruments. In this study, we evaluated amplified DNA concentrations measured using the colorimetric LAMP assay of the 1POT™ Professional device (1drop Inc, Korea). Results of the 1POT analysis of clinical samples were compared with measurements obtained from the Qubit™ 4 and NanoDrop™ 2000 devices (both from Thermo Fisher Scientific, MA, USA). These results showed a correlation of 0.98 (95% CI: 0.96-0.99) and 0.96 (95% CI: 0.92-0.98) between 1POT and the Qubit and NanoDrop. 1POT can measure amplified DNA accurately and is suitable for on-site molecular diagnostics.


Assuntos
Colorimetria , DNA , DNA/genética , DNA/análise , Técnicas de Amplificação de Ácido Nucleico/métodos , Técnicas de Diagnóstico Molecular/métodos , Sensibilidade e Especificidade
5.
Appl Environ Microbiol ; 89(12): e0090223, 2023 12 21.
Artigo em Inglês | MEDLINE | ID: mdl-38047632

RESUMO

IMPORTANCE: The first critical step in timely disease management is rapid disease identification, which is ideally on-site detection. Of all the technologies available for disease identification, nucleic acid amplification-based diagnostics are often used due to their specificity, sensitivity, adaptability, and speed. However, the modules to interpret amplification results rapidly, reliably, and easily in resource-limited settings at point-of-need (PON) are in high demand. Therefore, we developed a portable, low-cost, and easy-to-perform device that can be used for amplification readout at PON to enable rapid yet reliable disease identification by users with minimal training.


Assuntos
Técnicas de Amplificação de Ácido Nucleico , Sistemas Automatizados de Assistência Junto ao Leito , Técnicas de Amplificação de Ácido Nucleico/métodos
6.
J Econ Entomol ; 116(6): 1982-1989, 2023 12 11.
Artigo em Inglês | MEDLINE | ID: mdl-37852754

RESUMO

Ceratitis is an economically important genus of fruit flies that originated in Africa, has a wide host range, and causes serious economic losses due to its invasive damage. As a result, it is critical to identify them accurately and quickly in the world. Loop-mediated isothermal amplification (LAMP), as one of the representatives of isothermal amplification technology, has been widely used in the rapid nucleic acid detection of human pathogens and has shown its advantages in the identification of insect agricultural pests. In this study, using the mitochondrial cox1 and cob genes as target genes, the rapid molecular identification of the Ceratitis FARQ complex, C. cosyra, and C. capitata was realized based on LAMP. The experimental conditions optimization results showed that F3/B3:FIP/BIP = 1:8 was the optimal primer concentration ratio and 63 °C was the optimal reaction temperature. The sensitivity of the primers obtained in this study can reach up to 0.01 ng/µl DNA. A loop-mediated isothermal amplification identification technology system was established based on rapid, rough DNA extraction and visual detection of Ceratitis economically important fruit flies. The positive reaction system changed from pink to khaki by visual detection. The identification flow can be completed within 1 hour, including sample processing, DNA extraction, and LAMP visual detection.


Assuntos
Tephritidae , Humanos , Animais , Tephritidae/genética , Técnicas de Amplificação de Ácido Nucleico/métodos , Drosophila/genética , DNA , Sensibilidade e Especificidade
7.
Biosensors (Basel) ; 13(7)2023 Jul 12.
Artigo em Inglês | MEDLINE | ID: mdl-37504122

RESUMO

Emerging infectious diseases pose a serious threat to human health and affect social stability. In recent years, the epidemic situation of emerging infectious diseases is very serious; among these infectious diseases, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has affected many countries and regions in a short time. The prevention and treatment of these diseases require rapid on-site detection methods. However, the common detection method, RT-PCR, requires expensive instruments, complex operations, and professional operators. Here, we developed a portable low-cost assay for rapid on-site detection of viral nucleic acid using reverse transcription-loop-mediated isothermal amplification (RT-LAMP). The SARS-CoV-2 RNA can be successfully amplified within 15 min in a thermos, and the detection result is read rapidly in a portable low-cost device with a sensitivity of 100 copies/µL. The portable low-cost device consists of a black box, a laser or LED and a filter, costing only a few cents. The rapid on-site detection method can provide strong support for the control of biological threats such as infectious diseases. It is also an emergency detection method for low-resource settings, relieving the huge pressure on health care.


Assuntos
COVID-19 , Doenças Transmissíveis Emergentes , Humanos , SARS-CoV-2/genética , COVID-19/diagnóstico , RNA Viral , Técnicas de Diagnóstico Molecular/métodos , Técnicas de Amplificação de Ácido Nucleico/métodos , Sensibilidade e Especificidade
8.
Biosensors (Basel) ; 13(6)2023 Jun 14.
Artigo em Inglês | MEDLINE | ID: mdl-37367017

RESUMO

The five recognized zoonotic foodborne pathogens, namely, Listeria monocytogenes, Staphylococcus aureus, Streptococcus suis, Salmonella enterica and Escherichia coli O157:H7, pose a major threat to global health and social-economic development. These pathogenic bacteria can cause human and animal diseases through foodborne transmission and environmental contamination. Rapid and sensitive detection for pathogens is particularly important for the effective prevention of zoonotic infections. In this study, rapid and visual europium nanoparticle (EuNP)-based lateral flow strip biosensors (LFSBs) combined with recombinase polymerase amplification (RPA) were developed for the simultaneous quantitative detection of five foodborne pathogenic bacteria. Multiple T lines were designed in a single test strip for increasing the detection throughput. After optimizing the key parameters, the single-tube amplified reaction was completed within 15 min at 37 °C. The fluorescent strip reader recorded the intensity signals from the lateral flow strip and converted the data into a T/C value for quantification measurement. The sensitivity of the quintuple RPA-EuNP-LFSBs reached a level of 101 CFU/mL. It also exhibited good specificity and there was no cross-reaction with 20 non-target pathogens. In artificial contamination experiments, the recovery rate of the quintuple RPA-EuNP-LFSBs was 90.6-101.6%, and the results were consistent with those of the culture method. In summary, the ultrasensitive bacterial LFSBs described in this study have the potential for widespread application in resource-poor areas. The study also provides insights in respect to multiple detection in the field.


Assuntos
Técnicas Biossensoriais , Nanopartículas Metálicas , Animais , Humanos , Recombinases , Európio , Sensibilidade e Especificidade , Microbiologia de Alimentos , Técnicas de Amplificação de Ácido Nucleico/métodos
9.
Phytopathology ; 113(3): 567-576, 2023 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-36222536

RESUMO

Tomato chlorotic spot virus (TCSV) is a highly destructive, thrips-transmitted, emerging orthotospovirus in various vegetable and ornamental crops. It is important to reduce the risk of spreading this virus by limiting the movement of infected plant materials to other geographic areas by utilizing point-of-care diagnostics. Current diagnostic assays for TCSV require costly lab equipment, skilled personnel, and electricity. Here, we report the development of a simple rechargeable battery-operated handwarmer-assisted reverse transcription-loop-mediated isothermal amplification (RT-LAMP) assay and demonstrate a step-by-step protocol to achieve in-field detection of TCSV. Under field conditions, handwarmer-assisted RT-LAMP can detect as little as 0.9 pg/µl of total RNA from TCSV-infected tomato plants in <35 min. When fully charged, the field-portable device can be used in six consecutive RT-LAMP detection assays, yielding test results for 96 individual samples. Dye-based colorimetric methods, including pH and metal ion indicators, were evaluated to eliminate laboratory-dependent LAMP visualization. Phenol red combined with hydroxynaphthol blue was adopted in the handwarmer-assisted RT-LAMP detection method to obtain a more robust color difference distinguishable by the naked eye. Overall, handwarmer-assisted RT-LAMP is a rapid, highly sensitive, and cost-effective diagnostic technique that can be used by nonspecialist personnel in the field, particularly in rural production areas lacking access to a diagnostic lab or constant electricity. [Formula: see text] Copyright © 2023 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.


Assuntos
Solanum lycopersicum , Doenças das Plantas , Técnicas de Amplificação de Ácido Nucleico/métodos , Transcrição Reversa , Sensibilidade e Especificidade , Técnicas de Diagnóstico Molecular
10.
Diagn Microbiol Infect Dis ; 105(2): 115862, 2023 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-36493571

RESUMO

The spread of vector habitats along with increasing human mobility can introduce atypical Leishmania species and hence can challenge existing diagnostic practices for rapid detection of active infection with species outside the narrow target range. Here we assessed the pan-Leishmania detection ability of isothermal recombinase polymerase amplification (RPA) assays targeting 18S rRNA gene, cathepsin L-like cysteine proteinase B (Cpb) gene, and kinetoplast minicircle DNA (kDNA) regions. While the lowest limit of detection of the 18S rRNA-RPA and Cpb-RPA assays were estimated as 12 and 17 standard DNA molecules, respectively, both assays could amplify genomic DNA of 7 pathogenic Leishmania species. Evaluation of 18S rRNA-RPA and our previously developed kDNA-RPA assays on 70 real-time PCR-positive leishmaniasis samples of varying pathologies resulted in sensitivity rates of 35.71% and 88.57%, respectively, while the combined sensitivity was 98.57%. Combinatorial application of 18S rRNA-RPA and kDNA-RPA assays can be recommended for further diagnostic assessments.


Assuntos
Leishmania , Humanos , DNA de Cinetoplasto/genética , Leishmania/genética , Leishmania/isolamento & purificação , Técnicas de Amplificação de Ácido Nucleico/métodos , Recombinases/genética , RNA Ribossômico 18S/genética , Sensibilidade e Especificidade , Leishmaniose/diagnóstico
11.
Mol Biochem Parasitol ; 252: 111529, 2022 11.
Artigo em Inglês | MEDLINE | ID: mdl-36374724

RESUMO

BACKGROUND: Chinese citizens traveling abroad bring back imported malaria cases to China. Current malaria diagnostic tests, including microscopy and antigen-detecting rapid tests, cannot reliably detect low-density infections. To complement existing diagnostic methods, we aimed to develop a new loop-mediated isothermal amplification (LAMP) assay to detect and identify Plasmodium falciparum in Chinese travelers returning from Africa. METHODS: We developed a miniaturized LAMP assay to amplify the actin I gene of P. falciparum. Each reaction consumed only 25% of the reagents used in a conventional LAMP assay and the same amount of DNA templates used in nested PCR. We evaluated this LAMP assay's performance and compared it to microscopy and a nested PCR assay using 466 suspected malaria cases imported from Africa. We assessed the sensitivity of the new LAMP assay using cultured P. falciparum, clinical samples, and a plasmid construct, allowing unprecedented precision when quantifying the limit of detection. RESULTS: The new LAMP assay was highly sensitive and detected two more malaria cases than nested PCR. Compared to nested PCR, the sensitivity and specificity of the novel LAMP assay were 100% [95% confidence interval (CI) 98.5-100%] and 99.1% (95% CI 96.7-99.9%), respectively. When evaluated using serial dilutions of the plasmid construct, the detection limit of the new LAMP was as low as 102 copies/µL, 10-fold lower than PCR. The LAMP assay detected 0.01 parasites/µL of blood (equal to 0.04 parasites/µL of DNA) using cultured P. falciparum and 1-7 parasites/µL of blood (4-28 parasites/µL of DNA) in clinical samples, which is as good as or better than previously reported and commercially licensed assays. CONCLUSION: The novel LAMP assay based on the P. falciparum actin I gene was specific, sensitive, and cost-effective, as it consumes 1/4 of the reagents in a typical LAMP reaction.


Assuntos
Malária Falciparum , Malária , Humanos , Plasmodium falciparum/genética , Actinas/genética , Técnicas de Amplificação de Ácido Nucleico/métodos , Técnicas de Diagnóstico Molecular/métodos , Malária Falciparum/diagnóstico , Sensibilidade e Especificidade , África
12.
Nature ; 611(7936): 570-577, 2022 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-36352231

RESUMO

Expanding our global testing capacity is critical to preventing and containing pandemics1-9. Accordingly, accessible and adaptable automated platforms that in decentralized settings perform nucleic acid amplification tests resource-efficiently are required10-14. Pooled testing can be extremely efficient if the pooling strategy is based on local viral prevalence15-20; however, it requires automation, small sample volume handling and feedback not available in current bulky, capital-intensive liquid handling technologies21-29. Here we use a swarm of millimetre-sized magnets as mobile robotic agents ('ferrobots') for precise and robust handling of magnetized sample droplets and high-fidelity delivery of flexible workflows based on nucleic acid amplification tests to overcome these limitations. Within a palm-sized printed circuit board-based programmable platform, we demonstrated the myriad of laboratory-equivalent operations involved in pooled testing. These operations were guided by an introduced square matrix pooled testing algorithm to identify the samples from infected patients, while maximizing the testing efficiency. We applied this automated technology for the loop-mediated isothermal amplification and detection of the SARS-CoV-2 virus in clinical samples, in which the test results completely matched those obtained off-chip. This technology is easily manufacturable and distributable, and its adoption for viral testing could lead to a 10-300-fold reduction in reagent costs (depending on the viral prevalence) and three orders of magnitude reduction in instrumentation cost. Therefore, it is a promising solution to expand our testing capacity for pandemic preparedness and to reimagine the automated clinical laboratory of the future.


Assuntos
Automação , Teste para COVID-19 , Imãs , Técnicas de Diagnóstico Molecular , Técnicas de Amplificação de Ácido Nucleico , Robótica , SARS-CoV-2 , Humanos , COVID-19/diagnóstico , COVID-19/virologia , Teste para COVID-19/métodos , Técnicas de Diagnóstico Molecular/economia , Técnicas de Diagnóstico Molecular/métodos , Técnicas de Amplificação de Ácido Nucleico/economia , Técnicas de Amplificação de Ácido Nucleico/métodos , Pandemias/prevenção & controle , RNA Viral/análise , RNA Viral/genética , SARS-CoV-2/genética , SARS-CoV-2/isolamento & purificação , Sensibilidade e Especificidade , Algoritmos , Automação/economia , Automação/métodos , Robótica/métodos , Indicadores e Reagentes/economia
13.
Biosens Bioelectron ; 214: 114490, 2022 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-35793606

RESUMO

The rapid, reliable, ultra-sensitive, and cost-saving detection of Listeria monocytogenes (L. monocytogenes) has substantial implications for food safety. Thus, we developed a novel, enzyme-free, dual-signal amplification approach to detect L. monocytogenes based on the micro-orifice resistance technique combined with the aggregation of polystyrene (PS) microspheres constructed by the catalytic hairpin assembly reaction (CHA). Both the detection probes (probe2) and trigger DNA (tDNA) were first modified on PS microspheres (probe2-PS-tDNA). The tDNA was enriched by PS microspheres for the first signal amplification. After the hybridization reaction (the capture probes (probe1), target DNA, and probe2), unreacted probe2-PS-tDNA was removed, and the complex triggered the CHA reaction for the second signal amplification. Additionally, the micro-orifice resistance technique can sensitively identify PS microsphere aggregation caused by the CHA reaction to analyze the target DNA quantitatively. The CHA-mediated micro-orifice resistance assay was constructed by combining cost-saving PS microsphere probes, the highly specific DNA hybridization reaction, and the enzyme-free signal amplification strategy, substantially reducing the cost and improving the detection sensitivity (the limit of detection is 4 CFU/mL). This study provides a superior means to detect L. monocytogenes in complex food samples.


Assuntos
Técnicas Biossensoriais , Listeria monocytogenes , Técnicas Biossensoriais/métodos , DNA/genética , Limite de Detecção , Listeria monocytogenes/genética , Técnicas de Amplificação de Ácido Nucleico/métodos
14.
Genet Test Mol Biomarkers ; 26(4): 191-197, 2022 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-35394799

RESUMO

Aim: A common problem in forensic practice is the lack of sufficient amounts of good quality genomic DNA. A possible solution is the amplification of the available genomic DNA before locus-specific polymerase chain reaction (PCR) analysis. The aim of this study was to evaluate multiple annealing and looping-based amplification cycle (MALBAC)-based whole-genome amplification (WGA) for short tandem repeat (STR) genotyping of low copy number DNA (LCN-DNA). Materials and Methods: DNA isolated from five blood samples was quantified and diluted to 250, 150, 100, 50, 25, and 5 pg/µL. After preamplification with MALBAC, WGA products were quantified. PCR-STR genotyping was performed in triplicate using dilution or purification-treated WGA products for each level of DNA. STR profiles were analyzed and compared with that from non-WGA DNA. Results: The purification treatment performed better than dilution of the MALBAC-based WGA products. Compared with the non-WGA DNA, both the average number and peak heights of correct alleles were significantly improved after preamplification with the MALBAC-based WGA at DNA inputs of ≤50 pg. Like other WGA methods, allele dropout and allele drop-in were observed in the profiling results for many samples. Conclusions: MALBAC shows great potential in LCN-DNA analysis and could find broader application in the fields of forensics and genetics.


Assuntos
Variações do Número de Cópias de DNA , Repetições de Microssatélites , DNA/análise , DNA/genética , Variações do Número de Cópias de DNA/genética , Impressões Digitais de DNA/métodos , Genoma Humano/genética , Genótipo , Humanos , Repetições de Microssatélites/genética , Técnicas de Amplificação de Ácido Nucleico/métodos
15.
PLoS One ; 17(4): e0266703, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35404944

RESUMO

In 2019 a newly identified coronavirus, designated as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has spread rapidly from the epicenter in Wuhan (China) to more than 150 countries around the world, causing the Coronavirus disease 2019 (COVID-19) pandemic. In this study, we describe an extraction-less method based on reverse transcriptase loop-mediated isothermal amplification (RT-LAMP) intended for the rapid qualitative detection of nucleic acid from SARS-CoV-2 in upper respiratory specimens, including oropharyngeal and nasopharyngeal swabs, anterior nasal and mid-turbinate nasal swabs, nasopharyngeal washes/aspirates or nasal aspirates as well as bronchoalveolar lavage (BAL) from individuals suspected of COVID-19 by their healthcare provider. The assay's performance was evaluated and compared to an RT quantitative PCR-based assay (FDA-approved). With high sensitivity, specificity, and bypassing the need for RNA extraction, the RT-LAMP Rapid Detection assay is a valuable and fast test for an accurate and rapid RNA detection of the SARS-CoV-2 virus and potentially other pathogens. Additionally, the versatility of this test allows its application in virtually every laboratory setting and remote location where access to expensive laboratory equipment is a limiting factor for testing during pandemic crises.


Assuntos
COVID-19 , SARS-CoV-2 , COVID-19/diagnóstico , Análise Custo-Benefício , Humanos , Técnicas de Diagnóstico Molecular/métodos , Técnicas de Amplificação de Ácido Nucleico/métodos , RNA Viral/genética , SARS-CoV-2/genética , Sensibilidade e Especificidade
16.
Biosens Bioelectron ; 202: 113994, 2022 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-35042129

RESUMO

The pandemic due to the outbreak of 2019 coronavirus disease (COVID-19) caused by novel severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) has raised significant public health concerns. Rapid, affordable, and accurate diagnostic testing not only paves the way for the effective treatment of diseases, but also plays a crucial role in preventing the spreading of infectious diseases. Herein, a one-pot CRISPR/Cas13a-based visual biosensor was proposed and developed for the rapid and low-cost nucleic acid detection. By combining Cas13a cleavage and Recombinase Polymerase Amplification (RPA) in a one-pot reaction in a disposable tube-in-tube vessel, amplicon contamination could be completely avoided. The RPA reaction is carried out in the inner tube containing two hydrophobic holes at the bottom. After the completion of amplification reaction, the reaction solution enters the outer tube containing pre-stored Cas13a reagent under the action of centrifugation or shaking. Inner and outer tubes are combined to form an independent reaction pot to complete the nucleic acid detection without opening the lid. This newly developed nucleic acid detection method not only meets the need of rapid nucleic acid detection at home without the need for any specialized equipment, but also fulfils the requirement of rapid on-site nucleic acid detection with the aid of small automated instruments. In this study, CRISPR/Cas13a and CRISPR/Cas12a were used to verify the reliability of the developed one-pot nucleic acid detection method. The performance of the system was verified by detecting the DNA virus, i.e., African swine fever virus (ASFV) and the RNA virus, i.e., SARS-Cov-2. The results indicate that the proposed method possesses a limit of detection of 3 copy/µL. The negative and positive test results are consistent with the results of real-time fluorescence quantitative polymerase chain reaction (PCR), but the time required is shorter and the cost is lower. Thus, this study makes this method available in resource-limited areas for the purpose of large-scale screening and in case of epidemic outbreak.


Assuntos
Vírus da Febre Suína Africana , Técnicas Biossensoriais , COVID-19 , Ácidos Nucleicos , Animais , Sistemas CRISPR-Cas , Humanos , Técnicas de Amplificação de Ácido Nucleico/métodos , RNA Viral/genética , Reprodutibilidade dos Testes , SARS-CoV-2 , Sensibilidade e Especificidade , Suínos
17.
PLoS One ; 17(1): e0259886, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35081119

RESUMO

COVID-19 has exposed stark inequalities between resource-rich and resource-poor countries. International UN- and WHO-led efforts, such as COVAX, have provided SARS-CoV-2 vaccines but half of African countries have less than 2% vaccinated in their population, and only 15 have reached 10% by October 2021, further disadvantaging local economic recovery. Key for this implementation and preventing further mutation and spread is the frequency of voluntary [asymptomatic] testing. It is limited by expensive PCR and LAMP tests, uncomfortable probes deep in the throat or nose, and the availability of hardware to administer in remote locations. There is an urgent need for an inexpensive "end-to-end" system to deliver sensitive and reliable, non-invasive tests in resource-poor and field-test conditions. We introduce a non-invasive saliva-based LAMP colorimetric test kit and a $51 lab-in-a-backpack system that detects as few as 4 viral RNA copies per µL. It consists of eight chemicals, a thermometer, a thermos bottle, two micropipettes and a 1000-4000 rcf electronically operated centrifuge made from recycled computer hard drives (CentriDrive). The centrifuge includes a 3D-printed rotor and a 12 V rechargeable Li-ion battery, and its 12 V standard also allows wiring directly to automobile batteries, to enable field-use of this and other tests in low infrastructure settings. The test takes 90 minutes to process 6 samples and has reagent costs of $3.5 per sample. The non-invasive nature of saliva testing would allow higher penetration of testing and wider adoption of the test across cultures and settings (including refugee camps and disaster zones). The attached graphical procedure would make the test suitable for self-testing at home, performing it in the field, or in mobile testing centers by minimally trained staff.


Assuntos
COVID-19/diagnóstico , Técnicas de Diagnóstico Molecular/métodos , Técnicas de Amplificação de Ácido Nucleico/métodos , RNA Viral/análise , COVID-19/virologia , Teste de Ácido Nucleico para COVID-19/economia , Teste de Ácido Nucleico para COVID-19/métodos , Colorimetria , Humanos , Técnicas de Diagnóstico Molecular/economia , Técnicas de Diagnóstico Molecular/instrumentação , Técnicas de Amplificação de Ácido Nucleico/economia , Técnicas de Amplificação de Ácido Nucleico/instrumentação , Sistemas Automatizados de Assistência Junto ao Leito , RNA Viral/metabolismo , SARS-CoV-2/genética , SARS-CoV-2/isolamento & purificação , Saliva/virologia
18.
PLoS One ; 16(11): e0260348, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34843518

RESUMO

OBJECTIVES: Human parechovirus (HPeV), especially HPeV A3 (HPeV3), causes sepsis-like diseases and sudden infant death syndrome in neonates and young infants. Development of rapid and easier diagnostic laboratory tests for HPeVs is desired. METHODS: Original inner primers, outer primers, and loop-primers were designed on the 5' untranslated region of HPeV3. HPeV3 ribonucleic acids (RNAs), other viral RNAs, and clinical stool samples were used to confirm whether the designed primers would allow the detection of HPeV3 with the reverse transcription loop-mediated isothermal amplification (RT-LAMP) technique. RESULTS: Three combinations of primers were created and it was confirmed that all primer sets allowed the detection of HPeV3 RNAs. The primer sets had cross-reactivity with HPeV type 1 (HPeV1), but all sets showed negative results when applied to coxsackievirus, echovirus, enterovirus, norovirus, and adenovirus genomes. Four of six stool samples, obtained from newborn and infant patients with sepsis-like symptoms, showed positive results with our RT-LAMP technique. CONCLUSIONS: This manuscript is the first description of an RT-LAMP for the diagnosis of HPeVs, allowing a faster, easier, and cheaper diagnosis. This technique is clinically useful for newborns and infants who have sepsis-like symptoms.


Assuntos
Técnicas de Diagnóstico Molecular/métodos , Técnicas de Amplificação de Ácido Nucleico/métodos , Parechovirus/isolamento & purificação , Infecções por Picornaviridae/diagnóstico , Humanos , Lactente , Recém-Nascido , Técnicas de Diagnóstico Molecular/economia , Técnicas de Amplificação de Ácido Nucleico/economia , Parechovirus/genética , Infecções por Picornaviridae/virologia , RNA Viral/análise , RNA Viral/genética , Sensibilidade e Especificidade , Fatores de Tempo
20.
STAR Protoc ; 2(4): 100878, 2021 12 17.
Artigo em Inglês | MEDLINE | ID: mdl-34604812

RESUMO

Here, we describe a detailed step-by-step protocol to detect SARS-CoV-2 RNA using RT-PCR-mediated amplification and CRISPR/Cas-based visualization. The optimized assay uses basic molecular biology equipment such as conventional thermocyclers and transilluminators for qualitative detection. Alternatively, a fluorescence plate reader can be used for quantitative measurements. The protocol detects two regions of the SARS-CoV-2 genome in addition to the human RNaseP sample control. Aiming to reach remote regions, this work was developed to use the portable molecular workstation from BentoLab. For complete details on the use and execution of this protocol, please refer to Alcántara et al., 2021.


Assuntos
COVID-19/diagnóstico , Sistemas CRISPR-Cas , Técnicas de Amplificação de Ácido Nucleico/métodos , RNA Viral/análise , RNA Viral/genética , SARS-CoV-2/genética , COVID-19/genética , COVID-19/virologia , Humanos , SARS-CoV-2/isolamento & purificação
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