ABSTRACT
West Nile virus (WNV) causes West Nile fever and West Nile encephalitis. Because infection by WNV creates serious public health problems, its simple, rapid, and visual detection is very important in clinical practice, especially in resource-limited laboratories. We have developed a rapid, specific, and highly sensitive internally controlled reverse transcription recombinase-aided amplification (RTRAA) assay to detect WNV, using both real-time fluorescence and the lateral flow dipstick (LFD) at 39.0 °C for 30 min. The analytical sensitivity of the RT-RAA assay was 10 plasmid copies and 1.6 pfu per reaction with real-time fluorescence, and 1,000 plasmid copies per reaction with the LFD. No crossreaction with other control viruses was observed. Compared with the RT-qPCR assay, the RT-RAA assay demonstrated 100% sensitivity and 100% specificity for WNV.
ABSTRACT
Paratuberculosis (Johne's disease) is a chronic debilitating disease of domestic and wild ruminants. However, widespread point-of-care testing is infrequent due to the lack of a robust method. The isothermal recombinase polymerase amplification (RPA) technique has applied for rapid diagnosis. Herein, RPA combined with a lateral flow dipstick (LFD) assay was developed to estimate DNA from Mycobacterium avium subsp. paratuberculosis. First, analytical specificity and sensitivity of the RPA-nfo primer and probe sets were assessed. The assay successfully detected M. paratuberculosis DNA in 30 min at 39℃ with a detection limit of up to eight copies per reaction, which was equivalent to that of the real-time quantitative polymerase chain reaction (qPCR) assay. The assay was specific, as it did not amplify genomes from five other Mycobacterium spp. or five pathogenic enteric bacteria. Six hundred-twelve clinical samples (320 fecal and 292 serum) were assessed by RPA-LFD, qPCR, and enzyme-linked immunosorbent assay, respectively. The RPA-LFD assay yielded 100% sensitivity, 97.63% specificity, and 98.44% concordance rate with the qPCR results. This is the first report utilizing an RPA-LFD assay to visualize and rapidly detect M. paratuberculosis. Our results show this assay should be a useful method for the diagnosis of paratuberculosis in resource-constrained settings.
Subject(s)
Animals , Diagnosis , DNA , Enterobacteriaceae , Enzyme-Linked Immunosorbent Assay , Genome , Limit of Detection , Methods , Mycobacterium avium , Mycobacterium , Paratuberculosis , Point-of-Care Testing , Polymerase Chain Reaction , Recombinases , Ruminants , Sensitivity and SpecificityABSTRACT
Objective@#To establish a rapid and sensitive isothermal amplification assay for the detection of human Adenovirus.@*Methods@#Primers and probe used for recombinase polymerase amplification(RPA)were designed based on the conserved region of the adenoviruses hexon gene. After optimizing the reaction temperature and times, the products of RPA were detected by capillary electrophoresis and lateral flow dipstick(LFD). Sensitivity and specicity of the assay were evaluated. The diagnostic value of the RPA-LFD assay was verified using clinical samples which were simultaneously tested by real time PCR assay.@*Results@#The analytical sensitivity of RPA-LFD assay was 2 copies DNA molecules per reaction and no cross reaction with other pathogens was observed. Compared with real-time PCR assay, the sensitivity, and specificity of the present assay were all 100%.@*Conclusions@#The RPA-LFD assay developed in this study has the characteristics of high specificity, sensitivity, rapid and no requirement of expensive equipment which provided a new tool for rapid detection of human adenovirus.
ABSTRACT
Objective To develop a rapid, accurate, visual, and portable detection method for adenovirus types B (AdvB) and E ( AdvE).Methods Universal primers were targeted on type-specific conserved regions to allow the simultaneous detection of both human Adv (HAdV) species.A detection method based on the combination of recombinase polymerase amplification ( RPA) and lateral flow dipstick ( LFD) was established the sensitivity and specificity evaluated , and throat swab specimens of 19 patients infected with AdvB and AdvE as well as 10 healthy volunteers were detected with this method.Results The detection limit of the method was 10 copies/μl Adv DNA, which was close to that of qPCR , and there were no cross-reactions with other species of Adv and unrelated virus .The detection could be finished within 15 to 20 min within the temperature range of 25 to 45℃.When applied to clinical samples , this method showed 100% sensitivity and specificity.Conclusion This detection assay is a sensitive , specific, rapid and simple method that eliminates the need for expensive equipment , trained personnel or laboratories .The characteristics of this system render it suitable for use in grass-roots healthcare departments , and the system is especially effective for field testing and on-site testing.
ABSTRACT
Objective To develop a rapid, accurate, visual, and portable detection method for adenovirus types B (AdvB) and E ( AdvE).Methods Universal primers were targeted on type-specific conserved regions to allow the simultaneous detection of both human Adv (HAdV) species.A detection method based on the combination of recombinase polymerase amplification ( RPA) and lateral flow dipstick ( LFD) was established the sensitivity and specificity evaluated , and throat swab specimens of 19 patients infected with AdvB and AdvE as well as 10 healthy volunteers were detected with this method.Results The detection limit of the method was 10 copies/μl Adv DNA, which was close to that of qPCR , and there were no cross-reactions with other species of Adv and unrelated virus .The detection could be finished within 15 to 20 min within the temperature range of 25 to 45℃.When applied to clinical samples , this method showed 100% sensitivity and specificity.Conclusion This detection assay is a sensitive , specific, rapid and simple method that eliminates the need for expensive equipment , trained personnel or laboratories .The characteristics of this system render it suitable for use in grass-roots healthcare departments , and the system is especially effective for field testing and on-site testing.
ABSTRACT
Recombinase polymerase amplification (RPA) is a novel isothermal DNA amplification technology first re-ported in 2006 by Piepenburg et al.This technology has been shown to typically work at temperatures ranging from 25 to 43℃and can detect products within 5-20 min.RPA technology requires little instrumentation for the nucleic acid amplifi-cation reaction and can be performed not only in PCR tubes , but also in simple devices′such as paper .Combined with probe-based detection methods or lateral flow dipstick assay , it can perform quantitative or visual detection respectively . RPA is a technology that is potentially ideal for point-of-care diagnosis and disease prevention and control ,characterized by high sensitivity, high efficiency, high specificity and user-friendliness.This paper introduces the advantages and develop-ment of RPA technology in reaction conditions and product detection ,summarizes the current applications of this technolo-gy,and predicts the trend of application of RPA technology in point-of-care diagnosis and disease prevention and control .