Colorimetric loop-mediated isothermal amplification (LAMP) for cost-effective and quantitative detection of SARS-CoV-2: the change in color in LAMP-based assays quantitatively correlates with viral copy number

2021 ◽  
Author(s):  
Everardo González-González ◽  
Itzel Montserrat Lara-Mayorga ◽  
Iram Pablo Rodríguez-Sánchez ◽  
Yu Shrike Zhang ◽  
Sergio O. Martínez-Chapa ◽  
...  

Colorimetric LAMP for COVID-19 intensified diagnostics: a simple and quantitative method comparable in diagnostic performance to RT-qPCR.

2021 ◽  
pp. 095646242097112
Author(s):  
Jessica M Hughes ◽  
Darrell HS Tan ◽  
Peter Anderson ◽  
Janani Bodhinayake ◽  
Paul A MacPherson

HIV pre-exposure prophylaxis (PrEP) is effective at preventing sexual acquisition of HIV, and failures in clinical trials are largely attributable to medication nonadherence. We report here a case of infection with a fully susceptible strain of HIV in an individual adherent to PrEP as demonstrated by pharmacy records and intracellular tenofovir diphosphate levels. At diagnosis, the viral load was 90 copies/mL precluding initial genotype testing due to low copy number. While PrEP failure is rare, this case underscores the importance of regular HIV testing for patient on PrEP and prompts discussion regarding the approach to treatment following failure where an initial genotype is not yet available or not possible due to low viral load. Few other case reports of PrEP failure exist in the literature and approaches to treatment varied widely. We suggest the initial viral copy number may guide next steps and discuss the risks and benefits of stopping PrEP, escalating therapy with integrase inhibitors or boosted protease inhibitors, or switching to non-nucleoside antiretroviral treatment regimens.


1999 ◽  
Vol 15 (17) ◽  
pp. 1509-1518 ◽  
Author(s):  
D. H. Dockrell ◽  
A. D. Badley ◽  
A. Algeciras-Schimnich ◽  
M. Simpson ◽  
R. Schut ◽  
...  

2020 ◽  
Author(s):  
Lisa Oberding ◽  
Jia Hu ◽  
Byron Berenger ◽  
Abu Naser Mohon ◽  
Dylan R. Pillai

AbstractSaliva samples were collected through a simple mouth wash procedure and viral load quantified using a technology called digital droplet PCR. Data suggest ddPCR allows for precise quantification of viral load in clinical samples infected with SARS-CoV-2.


2017 ◽  
Vol 07 (03) ◽  
pp. 042-048
Author(s):  
Gunimala Chakraborty ◽  
Indrani Karunasagar ◽  
Anirban Chakraborty

AbstractDelivery of quality healthcare in case of an infectious disease depends on how efficiently and how quickly the responsible pathogens are detected from the samples. Molecular methods can detect the presence of pathogens in a rapid and sensitive manner. Over the years, a number of such assays have been developed. However, these methods, although highly reliable and efficient, require use of expensive equipment, reagents, and trained personnel. Therefore, development of molecular assays that are simple, rapid, cost-effective, yet sensitive, is highly warranted to ensure efficient management or treatment strategies. Loop-mediated isothermal amplification (LAMP), a technique invented in the year 2000, is a novel method that amplifies DNA at isothermal conditions. Since its invention, this technique has been one of the most extensively used molecular diagnostic tools in the field of diagnostics offering rapid, accurate and cost-effective diagnosis of infectious diseases. Using the LAMP principle, many commercial kits have been developed in the last decade for a variety of human pathogens including bacteria, viruses and parasites. Currently LAMP assay is being considered as an effective diagnostic tool for use in developing countries because of its simple working protocol, allowing even an onsite application. The focus of this review is to describe the salient features of this technique the current status of development of LAMP assays with an emphasis on the pathogens of clinical significance.


Viruses ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 972 ◽  
Author(s):  
Mohammed A. Rohaim ◽  
Emily Clayton ◽  
Irem Sahin ◽  
Julianne Vilela ◽  
Manar E. Khalifa ◽  
...  

Until vaccines and effective therapeutics become available, the practical solution to transit safely out of the current coronavirus disease 19 (CoVID-19) lockdown may include the implementation of an effective testing, tracing and tracking system. However, this requires a reliable and clinically validated diagnostic platform for the sensitive and specific identification of SARS-CoV-2. Here, we report on the development of a de novo, high-resolution and comparative genomics guided reverse-transcribed loop-mediated isothermal amplification (LAMP) assay. To further enhance the assay performance and to remove any subjectivity associated with operator interpretation of results, we engineered a novel hand-held smart diagnostic device. The robust diagnostic device was further furnished with automated image acquisition and processing algorithms and the collated data was processed through artificial intelligence (AI) pipelines to further reduce the assay run time and the subjectivity of the colorimetric LAMP detection. This advanced AI algorithm-implemented LAMP (ai-LAMP) assay, targeting the RNA-dependent RNA polymerase gene, showed high analytical sensitivity and specificity for SARS-CoV-2. A total of ~200 coronavirus disease (CoVID-19)-suspected NHS patient samples were tested using the platform and it was shown to be reliable, highly specific and significantly more sensitive than the current gold standard qRT-PCR. Therefore, this system could provide an efficient and cost-effective platform to detect SARS-CoV-2 in resource-limited laboratories.


2012 ◽  
Vol 102 (9) ◽  
pp. 899-907 ◽  
Author(s):  
Aravind Ravindran ◽  
Julien Levy ◽  
Elizabeth Pierson ◽  
Dennis C. Gross

This study reports the development of a loop-mediated isothermal amplification procedure (LAMP) for polymerase chain reaction (PCR)-based detection of ‘Candidatus Liberibacter solanacearum’, the bacterial causal agent of potato zebra chip (ZC) disease. The 16S rDNA gene of ‘Ca. Liberibacter solanacearum’ was used to design a set of six primers for LAMP PCR detection of the bacterial pathogen in potato plants and the psyllid vector. The advantage of the LAMP method is that it does not require a thermocycler for amplification or agarose gel electrophoresis for resolution. Positive LAMP results can be visualized directly as a precipitate. The LAMP strategy reported here reliably detected ‘Ca. Liberibacter solanacearum’ and the closely related species ‘Ca. Liberibacter asiaticus’, the causative agent of huanglongbing disease of citrus, in plant DNA extracts. Although not as sensitive as quantitative real-time PCR, LAMP detection was equivalent to conventional PCR in tests of ZC-infected potato plants from the field. Thus, the LAMP method shows strong promise as a reliable, rapid, and cost-effective method of detecting ‘Ca. Liberibacter’ pathogens in psyllids and field-grown potato plants and tubers.


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