scholarly journals Detection and discrimination of multiple strains of Zika virus by reverse transcription-loop-mediated isothermal amplification

2020 ◽  
Vol 48 (1) ◽  
Author(s):  
Hiroka Aonuma ◽  
Itoe Iizuka-Shiota ◽  
Tokio Hoshina ◽  
Shigeru Tajima ◽  
Fumihiro Kato ◽  
...  

Abstract Background Monitoring both invasion of Zika virus disease into free countries and circulation in endemic countries is essential to avoid a global pandemic. However, the difficulty lies in detecting Zika virus due to the large variety of mutations in its genomic sequence. To develop a rapid and simple method with high accuracy, reverse transcription-loop-mediated isothermal amplification (RT-LAMP) was adopted for the detection of Zika virus strains derived from several countries. Results Common primers for RT-LAMP were designed based on the genomic sequences of two standard Zika strains: African lineage, MR-766, and Asian lineage, PRVABC59. RT-LAMP reactions using a screened primer set, targeting the NS3 region, detected both Zika virus strains. The minimum detectable quantity was 3 × 10−2 ng of virus RNA. Measurable lag of reaction times among strains was observed. The RT-LAMP method amplified the target virus sequence from the urine and serum of a patient with a travel history in the Caribbean Islands and also provided a prediction about which lineage of Zika virus strain was present. Conclusions The RT-LAMP method using a well-optimized primer set demonstrated high specificity and sensitivity for the detection of Zika virus strains with a variety in genomic RNA sequences. In combination with the simplicity of LAMP reaction in isothermal conditions, the optimized primer set established in this study may facilitate rapid and accurate diagnosis of Zika fever patients with virus strain information.

2012 ◽  
Vol 2012 ◽  
pp. 1-5 ◽  
Author(s):  
Zhang Tie ◽  
Wang Chunguang ◽  
Wei Xiaoyuan ◽  
Zhao Xinghua ◽  
Zhong Xiuhui

To develop a rapid detection method ofStaphylococcus aureususing loop-mediated isothermal amplification (LAMP), four specific primers were designed according to six distinct sequences of thenucgene. In addition, the specificity and sensitivity of LAMP were verified and compared with those of PCR. Results showed that the LAMP reaction was completed within 45 min at 62.5°C, and ladder bands were appeared in LAMP products analyzed by gel electrophoresis. After adding 1x SYBR Green l, the positive reaction tube showed green color and the negative reaction tube remained orange, indicating that the LAMP has high specificity. The minimal detectable concentration of LAMP was1×102 CFU/mL and that of PCR was1×104 CFU/mL, indicating that the LAMP was 100 times more sensitive than the PCR. The LAMP method for detection ofStaphylococcus aureushas many advantages, such as simple operation, high sensitivity, high specificity, and rapid analysis. Therefore, this method is more suitable for the rapid on-site detection ofStaphylococcus aureus.


Author(s):  
Maryam ARFAATABAR ◽  
Narjes NOORI GOODARZI ◽  
Davoud AFSHAR ◽  
Hamed MEMARIANI ◽  
Ghasem AZIMI ◽  
...  

  Background: Mycoplasma pneumoniae is a common cause of community-acquired pneumonia (CAP) worldwide, especially among children and debilitated populations. The present study aimed to investigate a loop-mediated isothermal amplification (LAMP) technique for rapid detection of M. pneumoniae in clini-cal specimens collected from patients with pneumonia. Methods: Throat swabs were collected from 110 outpatients who suffered from pneumonia. Throat swab samples were obtained from patients referred to the hospital outpatient clinics of Tehran University hospitals, Iran in 2017. The presence of M. pneumoniae in the clinical specimens was evaluated by LAMP, PCR and culture methods. Sensitivity and specificity of the LAMP and PCR assays were also determined. Results: Out of 110 specimens, LAMP assay detected M. pneumoniae in 35 specimens. Detection limit of the LAMP assay was determined to be 33fg /μL or ~ 40 genome copies/reaction. Moreover, no cross-reaction with genomic DNA from other bacteria was observed. Only 25 specimens were positive by the culture method. The congruence between LAMP assay and culture method was ‘substantial’ (κ=0.77). Specificity and sensitivity of LAMP assay were 88.2%, 100% in compare with culture. However, the con-gruence between LAMP assay and PCR assay was ‘almost perfect’ (κ=0.86). Specificity and sensitivity of LAMP assay were 92.5%, 100% in compare with PCR. Conclusion: Overall, the LAMP assay is a rapid and cost-efficient laboratory test in comparison to other methods including PCR and culture. Therefore, the LAMP method can be applied in identification of M. pneumoniae isolates in respiratory specimens.


2013 ◽  
Vol 16 (1) ◽  
pp. 131-133 ◽  
Author(s):  
Ł. Adaszek ◽  
M. Jankowska ◽  
M. Kalinowski ◽  
T. Banach ◽  
D. Wułupek ◽  
...  

Abstract The aim of this study was to use a rapid and easy DNA-based test, the loop-mediated isothermal amplification (LAMP), for diagnosis of Babesia canis canis infections in dogs. 10 DNA samples of 18S RNA-A and 10 DNA samples of 18S RNA-B of B. canis canis were used in the study. LAMP method could successfully detect DNA in all examined samples down to 0.1 pg dilution. Obtained results suggest that this method has high specificity and sensitivity and can be applied in analytical laboratories in diagnosis of canine babesiosis.


2021 ◽  
Vol 12 ◽  
Author(s):  
Domenico Rizzo ◽  
Daniele Da Lio ◽  
Alessandra Panattoni ◽  
Chiara Salemi ◽  
Giovanni Cappellini ◽  
...  

Tomato brown rugose fruit virus (ToBRFV) represents an emerging viral threat to the productivity of tomato and pepper protected cultivation worldwide. This virus has got the status of quarantine organism in the European Union (EU) countries. In particular, tomato and pepper seeds will need to be free of ToBRFV before entering the EU and before coming on the market. Thus, lab tests are needed. Here, we develop and validate a one-step reverse transcription LAMP platform for the detection of ToBRFV in tomato and pepper leaves, by real-time assay [reverse transcription loop-mediated isothermal amplification (RT-LAMP)] and visual screening (visual RT-LAMP). Moreover, these methods can also be applied successfully for ToBRFV detection in tomato and pepper seeds. The diagnostic specificity and sensitivity of both RT-LAMP and visual RT-LAMP are both 100%, with a detection limit of nearly 2.25 fg/μl, showing the same sensitivity as RT-qPCR Sybr Green, but 100 times more sensitive than end-point RT-PCR diagnostic methods. In artificially contaminated seeds, the proposed LAMP assays detected ToBRFV in 100% of contaminated seed lots, for up to 0.025–0.033% contamination rates in tomato and pepper, respectively. Our results demonstrate that the proposed LAMP assays are simple, inexpensive, and sensitive enough for the detection of ToBRFV, especially in seed health testing. Hence, these methods have great potential application in the routine detection of ToBRFV, both in seeds and plants, reducing the risk of epidemics.


2020 ◽  
Vol 21 (8) ◽  
pp. 2826 ◽  
Author(s):  
Renfei Lu ◽  
Xiuming Wu ◽  
Zhenzhou Wan ◽  
Yingxue Li ◽  
Xia Jin ◽  
...  

COVID-19 has become a major global public health burden, currently causing a rapidly growing number of infections and significant morbidity and mortality around the world. Early detection with fast and sensitive assays and timely intervention are crucial for interrupting the spread of the COVID-19 virus (SARS-CoV-2). Using a mismatch-tolerant amplification technique, we developed a simple, rapid, sensitive and visual reverse transcription loop-mediated isothermal amplification (RT-LAMP) assay for SARS-CoV-2 detection based on its N gene. The assay has a high specificity and sensitivity, and robust reproducibility, and its results can be monitored using a real-time PCR machine or visualized via colorimetric change from red to yellow. The limit of detection (LOD) of the assay is 118.6 copies of SARS-CoV-2 RNA per 25 μL reaction. The reaction can be completed within 30 min for real-time fluorescence monitoring, or 40 min for visual detection when the template input is more than 200 copies per 25 μL reaction. To evaluate the viability of the assay, a comparison between the RT-LAMP and a commercial RT-qPCR assay was made using 56 clinical samples. The SARS-CoV-2 RT-LAMP assay showed perfect agreement in detection with the RT-qPCR assay. The newly-developed SARS-CoV-2 RT-LAMP assay is a simple and rapid method for COVID-19 surveillance.


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