Development and application of loop-mediated isothermal amplification label-based nanoparticles lateral flow biosensor for detection of Mycobacterium tuberculosis

2019 ◽  
Author(s):  
Xingyun Wang ◽  
Yi Wang ◽  
Weiwei Jiao ◽  
Guirong Wang ◽  
Yacui Wang ◽  
...  

Abstract Tuberculosis is a serious disease with high morbidity and mortality, thus rapid and cost-effective diagnostic test for Mycobacterium tuberculosis (MTB) is urgently needed. Here, a novel detection diagnostic technique, termed as loop-mediated isothermal amplification label-based nanoparticles with lateral flow biosensor (LAMP-LFB), was developed and evaluated for rapid, reliable and objective detection of MTB. Two sets of primers, which targeted IS 6110 and IS 1081 sequences of MTB, were simultaneously designed for establishment of LAMP-LFB assay. The optimal reaction conditions of MTB-LAMP-LFB assay confirmed were 66ºC for only 50min. The analytical sensitivity of MTB-LAMP-LFB is 10fg of genomic templates in pure culture, and the detection results obtained from LFB was in conformity with agarose gel electrophoresis. No cross-reactivity with other common bacteria and non-tuberculous mycobacteria strains (NTM) was obtained. A total of 158 clinical samples were collected from presumptive 158 TB patients, were used for evaluating the feasibility of MTB-LAMP-LFB assay. Among 98 TB patients diagnosed with composite reference standard, the positive rate for MTB detection using liquid culture, Xpert MTB/RIF and LAMP-LFB were 40.0% (39/98), 50.0% (48/98), and 86.7% (85/98), respectively. Among 39 culture confirmed samples, 84.6% (33/39) cases were Xpert MTB/RIF-positive and 92.3% (36/39) were LAMP-LFB-positive. For the 59 clinically diagnosed TB cases 25.4% (15/59) and 83.0% (49/59) were Xpert MTB/RIF-positive and LAMP-LFB positive, respectively. Therefore, MTB-LAMP-LFB assay is a simple, reliable, and sensitive method for MTB detection and maybe prospective in early diagnosis of MTB.

Author(s):  
Xingyun Wang ◽  
Guirong Wang ◽  
Yacui Wang ◽  
Shuting Quan ◽  
Hui Qi ◽  
...  

The aim of this study was to develop a simple and reliable method to detect Mycobacterium tuberculosis complex (MTBC) and verify its clinical application preliminarily. A loop-mediated isothermal amplification method coupled with lateral flow biosensor (LAMP-LFB) assay, was developed and evaluated for detection of MTBC. Two sets of primers, which targeted IS6110 and IS1081 sequences of MTBC, were designed for establishment of multiplex LAMP-LFB assay. The amplicons were labelled with biotin and fluorescein isothiocyanate (FITC) by adding FITC labelled primer and biotin-14-dATP and biotin-14-dCTP and could be visualized using LFB. The optimal reaction conditions of multiplex LAMP-LFB assay confirmed were 66°C for 50 min. The analytical sensitivity of multiplex LAMP-LFB is 10 fg of genomic templates using pure culture, and no cross-reactivity with other common bacteria and non-tuberculous mycobacteria strains was obtained. A total of 143 clinical samples collected from 100 TB patients (62 definite TB cases and 38 probable TB cases) and 43 non-TB patients were used for evaluating the feasibility of multiplex LAMP-LFB assay. The multiplex LAMP-LFB (82.0%, 82/100) showed higher sensitivity than culture (47.0%, 47/100, P < 0.001) and Xpert MTB/RIF (54.0%, 54/100, P < 0.001). Importantly, the multiplex LAMP-LFB assay detected additional 28 probable TB cases, which increased the percentage of definite TB cases from 62.0% (62/100) to 90.0% (90/100). The specificity of multiplex LAMP-LFB assay in patients without TB was 97.7% (42/43). Therefore, multiplex LAMP-LFB assay is a simple, reliable, and sensitive method for MTBC detection, especially in probable TB cases and resource limited settings.


PLoS ONE ◽  
2021 ◽  
Vol 16 (1) ◽  
pp. e0244753
Author(s):  
Jeeyong Kim ◽  
Borae G. Park ◽  
Da Hye Lim ◽  
Woong Sik Jang ◽  
Jeonghun Nam ◽  
...  

Introduction The rapid and accurate diagnosis of tuberculosis (TB) is important to reduce morbidity and mortality rates and risk of transmission. Therefore, molecular detection methods such as a real-time PCR–based assay for Mycobacterium tuberculosis (MTB) have been commonly used for diagnosis of TB. Loop-mediated isothermal amplification (LAMP) assay was believed to be a simple, quick, and cost-effective isothermal nucleic acid amplification diagnostic test for infectious diseases. In this study, we designed an in-house multiplex LAMP assay for the differential detection of MTB and non-tuberculosis mycobacterium (NTM), and evaluated the assay using clinical samples. Material and methods For the multiplex LAMP assay, two sets of specific primers were designed: the first one was specific for IS6110 genes of MTB, and the second one was universal for rpoB genes of mycobacterium species including NTM. MTB was confirmed with a positive reaction with both primer sets, and NTM was identified with a positive reaction by only the second primer set without a MTB-specific reaction. Total 333 clinical samples were analyzed to evaluate the multiplex LAMP assay. Clinical samples were composed of 195 positive samples (72 MTB and 123NTM) and 138 negative samples. All samples were confirmed positivity or negativity by real-time PCR for MTB and NTM. Analytical sensitivity and specificity were evaluated for the multiplex LAMP assay in comparison with acid fast bacilli staining and the culture method. Results Of 123 NTM samples, 121 were identified as NTM and 72/72 MTB were identified as MTB by the multiplex LAMP assay. False negative reactions were seen only in two NTM positive samples with co-infection of Candida spp. All 138 negative samples were identified as negative for MTB and NTM. Analytical sensitivity of the multiplex LAMP assay was 100% (72/72) for MTB, and 98.4% (121/123) for NTM. And the specificity of assay was 100% (138/138) for all. Conclusions Our newly designed multiplex LAMP assay for MTB and NTM showed relatively good sensitivity in comparison with previously published data to detect isolated MTB. This multiplex LAMP assay is expected to become a useful tool for detecting and differentiating MTB from NTM rapidly at an acceptable sensitivity.


2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Wansadaj Jaroenram ◽  
Jantana Kampeera ◽  
Narong Arunrut ◽  
Sarawut Sirithammajak ◽  
Sarinya Jaitrong ◽  
...  

Abstract Mycobacterium tuberculosis (Mtb) is an insidious scourge that has afflicted millions of people worldwide. Although there are many rapid methods to detect it based on loop-mediated isothermal amplification (LAMP) and a lateral flow dipstick (LFD), this study made further improvements using a new set of primers to enhance LAMP performance and a novel DNA probe system to simplify detection and increase specificity. The new probe system eliminates the post-LAMP hybridization step typically required for LFD assays by allowing co-hybridization and amplification of target DNA in one reaction while preventing self-polymerization that could lead to false-positive results. The improved assay was named Probe-Triggered, One-Step, Simultaneous DNA Hybridization and LAMP Integrated with LFD (SH-LAMP-LFD). SH-LAMP-LFD was simpler to perform and more sensitive than previously reported LAMP-LFD and PCR methods by 100 and 1000 times, respectively. It could detect a single cell of Mtb. The absence of cross-reactivity with 23 non-TB bacteria, and accurate test results with all 104 blind clinical samples have highlighted its accuracy. Its robustness and portability make SH-LAMP-LFD suitable for users in both low and high resource settings.


2018 ◽  
Vol 2018 ◽  
pp. 1-9 ◽  
Author(s):  
Timothy S. Mamba ◽  
Cecilia K. Mbae ◽  
Johnson Kinyua ◽  
Erastus Mulinge ◽  
Gitonga Nkanata Mburugu ◽  
...  

Background. Cryptosporidiumis a protozoan parasite and a major cause of diarrhea in children and immunocompromised patients. Current diagnostic methods for cryptosporidiosis such as microscopy have low sensitivity while techniques such as PCR indicate higher sensitivity levels but are seldom used in developing countries due to their associated cost. A loop-mediated isothermal amplification (LAMP) technique, a method with shorter time to result and with equal or higher sensitivity compared to PCR, has been developed and applied in the detection ofCryptosporidiumspecies. The test has a detection limit of 10 pg/µl (~100 oocysts/ml) indicating a need for more sensitive diagnostic tools. This study developed a more sensitive lateral flow dipstick (LFD) LAMP test based on SAM-1 gene and with the addition of a second set of reaction accelerating primers (stem primers).Results. The stem LFD LAMP test showed analytical sensitivity of 10 oocysts/ml compared to 100 oocysts/ml (10 pg/ul) for each of the SAM-1 LAMP test and nested PCR. The stem LFD LAMP and nested PCR detected 29/39 and 25/39 positive samples of previously identifiedC. parvumandC. hominisDNA, respectively. The SAM-1 LAMP detected 27/39. On detection ofCryptosporidiumDNA in 67 clinical samples, the stem LFD LAMP detected 16 samples and SAM-2 LAMP 14 and nested PCR identified 11. Preheating the templates increased detection by stem LFD LAMP to 19 samples. Time to results from master mix preparation step took ~80 minutes. The test was specific, and no cross-amplification was recorded with nontarget DNA.Conclusion.The developed stem LFD LAMP test is an appropriate method for the detection ofC. hominis, C. parvum,andC. meleagridisDNA in human stool samples. It can be used in algorithm with other diagnostic tests and may offer promise as an effective diagnostic tool in the control of cryptosporidiosis.


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.


2020 ◽  
Author(s):  
Mohammed A Rohaim ◽  
Emily Clayton ◽  
Irem Sahin ◽  
Julianne Vilela ◽  
Manar E Khalifa ◽  
...  

Until vaccines and effective therapeutics become available, the practical way to transit safely out of the current 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 result, 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 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. The system could provide an efficient and cost-effective platform to detect SARS-CoV-2 in resource-limited laboratories.


2019 ◽  
Vol 13 (12) ◽  
pp. 1135-1141 ◽  
Author(s):  
Yihong Hu ◽  
Zhenzhou Wan ◽  
Yonglin Mu ◽  
Yi Zhou ◽  
Jia Liu ◽  
...  

Introduction: Human respiratory syncytial virus (hRSV) is a common respiratory virus closely related to respiratory tract infection (RTI). Rapid and accurate detection of hRSV is urgently needed to reduce the high morbidity and mortality due to hRSV infection. Methodology: Here, we established a highly sensitive and specific reverse-transcription loop-mediated isothermal amplification (RT-LAMP) assay for the rapid detection of A and B group hRSV simultaneously. The specific primer sets for hRSV A and B groups were designed in the M and M2-2 gene, respectively. SYTO 9 was used as the fluorescent dye for real-time monitoring of the amplification of hRSV RNA without cross reaction between hRSV A and B. Results: The limit of detection (LOD) of our new method was 281.17 50% tissue culture infective doses (TCID50)/mL for hRSV A and 1.58 TCID50/mL for hRSV B. Using 90 clinical samples, a comparison to traditional RT-PCR was performed to validate this assay. The positivity rate of RT-LAMP and RT-PCR were 67.8% and 55.6%, respectively, and the positivity rate of RT-LAMP was significantly higher than RT-PCR (χ2 test, P < 0.01). Conclusions: Compared with traditional RT-PCR method, the newly developed fluorescent RT-LAMP combined with well-designed primers and SYTO 9 is quite sensitive, specific, rapid and well applicable to hRSV clinical diagnosis.


2016 ◽  
Vol 2016 ◽  
pp. 1-8 ◽  
Author(s):  
Jutturong Ckumdee ◽  
Thongchai Kaewphinit ◽  
Kosum Chansiri ◽  
Somchai Santiwatanakul

Multidrug resistant tuberculosis (MDR-TB) is Mycobacterium tuberculosis that does not respond to isoniazid and rifampicin, so the condition worsens continuously and creates difficulties for treatment by public health control programmes, especially in developing countries. The real time polymerase chain reaction (PCR) combined with agarose gel electrophoresis or strip tests is useful molecular tools for diagnosis of MDR-TB. Novel loop-mediated isothermal amplification (LAMP) can also detect drug resistance, which is a one-point mutation, by designing inner primers of 5′ end specific with the mutant. Au-nanoprobes on hybridisation with LAMP products containing target-specific sequences remain red, whereas test samples without specific sequences in the probe turn purple due to salt-induced aggregation of the Au-nanoprobes. In this study, a strategy was designed based on the LAMP of a DNA sample coupled to specific Au-nanoprobes, which showed the potential to provide a rapid and sensitive method for detecting isoniazid resistance at katG gene position 315 (G→C). 46 clinical samples were tested and showed 100% specificity and sensitivity compared with Genotype® MDR-TB Plus. This method was advantageous because it is rapid, cheap, specific, and sensitive. Further, it does not require thermal cycles for MDR-TB detection.


2021 ◽  
Author(s):  
Luxi Jiang ◽  
Xiaomeng Li ◽  
Rumeng Gu ◽  
Ziling Shi ◽  
Meijun Song ◽  
...  

Abstract Legionella pneumophila ( L. pneumophila ) is the most pathogenic species of Legionella , which can cause Legionella disease. It can cause pneumonia, or Pontiac fever. In severe cases, it can lead to respiratory failure and kidney failure, with a high fatality rate. Here, a novel molecular diagnosis method, a loop-mediated isothermal amplification coupled with lateral flow biosensor (LFB) method (LAMP-LFB) was successfully established and evaluated for the identification of L. pneumophila . A set of 6 primers was designed specifically based on the L. pneumophila -specific gene mip. The optimized time and temperature conditions for the LAMP was 50 min and 64◦C respectively. The minimum concentration that can be detected by this method was 100fg. Using the protocol, we could observe the LAMP amplification within 2min by LFB. The whole process, including the preparation of DNA (20 min), LAMP reaction (50 min) and results reporting (2 min), could be finished within 75 min. Among 50 alveolar lavage fluid samples, 5(10%) were L. pneumophila -positive by the LAMP-LFB, and the diagnostic accuracy was 100% when compared to the culture method. While only 4 samples were positive using PCR method. In a word, the LAMP-LFB assay is a rapid, sensitive and specific detection method that can detect Legionella pneumophila , and it can be used as a new molecular method for the detection of target pathogens in water, environmental and clinical samples.


2021 ◽  
Vol 12 ◽  
Author(s):  
Xinggui Yang ◽  
Junfei Huang ◽  
Xu Chen ◽  
Ziyu Xiao ◽  
Xiaojuan Wang ◽  
...  

Tuberculosis (TB) is a chronic infectious disease mainly caused by Mycobacterium tuberculosis (MTB), but other members of the Mycobacterium tuberculosis complex (MTBC), especially Mycobacterium bovis (pyrazinamide-resistant organisms), may also be involved. Thus, the ability to rapidly detect and identify MTB from other MTBC members (e.g., M. bovis, Mycobacterium microti, Mycobacterium africanum) is essential for the prevention and treatment of TB. A novel diagnostic method for the rapid detection and differentiation of MTB, which employs multiplex loop-mediated isothermal amplification (mLAMP) combined with a nanoparticle-based lateral flow biosensor (LFB), was established (mLAMP-LFB). Two sets of specific primers that target the IS6110 and mtp40 genes were designed according to the principle of LAMP. Various pathogens were used to optimize and evaluate the mLAMP-LFB assay. The optimal conditions for mLAMP-LFB were determined to be 66°C and 40 min, and the amplicons were directly verified by observing the test lines on the biosensor. The LAMP assay limit of detection (LoD) was 125 fg per vessel for the pure genomic DNA of MTB and 4.8 × 103 CFU/ml for the sputum samples, and the analytical specificity was 100%. In addition, the whole process, including the clinical specimen processing (35 min), isothermal amplification (40 min), and result confirmation (1–2 min), could be completed in approximately 80 min. Thus, mLAMP-LFB is a rapid, reliable, and sensitive method that is able to detect representative members of MTBC and simultaneously differentiate MTB from other MTBC members, and it can be used as a potential screening tool for TB in clinical, field, and basic laboratory settings.


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