Abstract:Asymptomatic visceral leishmaniasis cases increase continuously, particularly among patients with HIV who are at risk to develop further symptoms of leishmaniasis. A simple, sensitive and reliable diagnosis is crucially needed due to risk populations mostly residing in rural communities with limited resources of laboratory equipment. In this study, a highly sensitive and selective determination of Leishmania among asymptomatic patients with Leishmania/HIV co-infection was achieved to simultaneously interpret a… Show more
“…Otherwise, the difference in distance between the negative control using Milli Q water without genomic DNA and the sample (the distance of a sample minus negative reference as a cutoff value) or ΔdPAD is performed to standardize the distance of LAMP reaction mixture between each pre-reaction preparation (2.2). The process of detecting and immobilizing DNA on the cellulose paper owing to the physical adsorption and the charge interaction between DNA and the immobilized cationic polymers has been described by Saengsawang et al 38 and Ruang-areerate et al 41 . Figure 1 Schematic procedure of E. coli screening and quantitative evaluation in urine using distance-based paper device (dPAD) LAMP assay.…”
Section: Resultsmentioning
confidence: 99%
“…Therefore, the technique is feasible and valuable for all levels of hospitals and, especially, point-of-care settings in resource-limited areas to aid in diagnosing UTIs 37 , 38 . In addition, due to its simplicity, LAMP was possibly combined with various methods and devices to increase the sensitivity and feasibility, for example, magnetic separation 31 , microfluidic impedimetric sensing 31 , AuNP colorimetric precipitates 39 , 40 , semi-quantitative dPADs 38 , 41 , 42 and microchips 43 .…”
Uropathogenic Escherichia coli (UPEC) causes up to 90% of urinary tract infections (UTI) which is more prevalent among females than males. In urine, patients with symptomatic UTI usually have a high concentration of bacterial infection, ≥ 105 colony-forming units (CFU) per mL, in which the culture method is regularly the gold standard diagnosis. In this study, a simple and inexpensive distance-based paper device (dPAD) combined with the fluorescent closed tube LAMP assay was validated for simultaneously screening and semi-quantifying the infection level of E. coli in 440 urine samples of patients with UTI. The dPAD could measure the LAMP amplicons and semi-quantify the levels of E. coli infection in heavy (≥ 104 CFU/mL), light (≤ 103 CFU/mL) and no infection. The sensitivity and specificity had reliable performances, achieving as high as 100 and 92.7%, respectively. The one step LAMP assay could be performed within 3 h, which was 7.5 times faster than the culture method. To empower early UTI diagnosis and fast treatment, this inexpensive dPAD tool combined with the fluorescent closed tube LAMP assay is simple, reliably fast and practically portable for point-of-care settings, particularly in resource-limited areas, which can be set up in all levels of healthcare facilities.
“…Otherwise, the difference in distance between the negative control using Milli Q water without genomic DNA and the sample (the distance of a sample minus negative reference as a cutoff value) or ΔdPAD is performed to standardize the distance of LAMP reaction mixture between each pre-reaction preparation (2.2). The process of detecting and immobilizing DNA on the cellulose paper owing to the physical adsorption and the charge interaction between DNA and the immobilized cationic polymers has been described by Saengsawang et al 38 and Ruang-areerate et al 41 . Figure 1 Schematic procedure of E. coli screening and quantitative evaluation in urine using distance-based paper device (dPAD) LAMP assay.…”
Section: Resultsmentioning
confidence: 99%
“…Therefore, the technique is feasible and valuable for all levels of hospitals and, especially, point-of-care settings in resource-limited areas to aid in diagnosing UTIs 37 , 38 . In addition, due to its simplicity, LAMP was possibly combined with various methods and devices to increase the sensitivity and feasibility, for example, magnetic separation 31 , microfluidic impedimetric sensing 31 , AuNP colorimetric precipitates 39 , 40 , semi-quantitative dPADs 38 , 41 , 42 and microchips 43 .…”
Uropathogenic Escherichia coli (UPEC) causes up to 90% of urinary tract infections (UTI) which is more prevalent among females than males. In urine, patients with symptomatic UTI usually have a high concentration of bacterial infection, ≥ 105 colony-forming units (CFU) per mL, in which the culture method is regularly the gold standard diagnosis. In this study, a simple and inexpensive distance-based paper device (dPAD) combined with the fluorescent closed tube LAMP assay was validated for simultaneously screening and semi-quantifying the infection level of E. coli in 440 urine samples of patients with UTI. The dPAD could measure the LAMP amplicons and semi-quantify the levels of E. coli infection in heavy (≥ 104 CFU/mL), light (≤ 103 CFU/mL) and no infection. The sensitivity and specificity had reliable performances, achieving as high as 100 and 92.7%, respectively. The one step LAMP assay could be performed within 3 h, which was 7.5 times faster than the culture method. To empower early UTI diagnosis and fast treatment, this inexpensive dPAD tool combined with the fluorescent closed tube LAMP assay is simple, reliably fast and practically portable for point-of-care settings, particularly in resource-limited areas, which can be set up in all levels of healthcare facilities.
“…The appropriate limit of quantification in these studies can be considered as a result of several factors involved in the preparation of the desired biosensor, including excellent electrical conductivity, structural properties, different marker and high stability of the AuNPs. A recent study using AuNP-probe and molecular methods outlined detection limits of 10 2 parasites/mL (0.0147 ng/µL) for the diagnosis of VL among human immunodeficiency virus (HIV) infected patients [ 29 ]. This method offered promising insights into the Leishmania spp., detection in a reliable and highly specific manner without any cross-reactivity with other similar agents.…”
Nanobiosensor platforms have emerged as convenient and promising approaches with remarkable efficacy for the diagnosis of infectious diseases. Gold nanoparticles (AuNPs) have been widely used due to numerous advantageous properties such as optical, electrical, physicochemical and great biomolecules binding capabilities. This study aimed to apply AuNP-Probe Conjugate for the detection of Leishmania spp., using colorimetric and amplification methods targeting parasitic ITS2 fragment. The first method was carried out by hybridization of 10µL of DNA with 4 µL of probe and addition of 5 µL of 0.2 N HCl (non-amplification method). Second method was followed by polymerase chain reaction (PCR) amplification using thiolated primer, 5 µL of AuNP and 5 µL of 0.2 N HCl. The appearance of red and purple colors indicated positive and negative results, respectively. The minimum of detection for non-amplification and amplification methods for three strains of Leishmania namely L. major, L. tropica and L. infantum were determined to be 32 fg/µL and 16 fg/µL, respectively. Sensitivity for detection of visceral leishmaniasis (VL) for non-amplification and amplification methods included 96% and 100%, respectively and for cutaneous leishmaniasis (CL) included 98% and 100%, respectively. The results of this investigation revealed that sensitivity of amplification method was the same as RT-qPCR, while that of non-amplification method was lower. However, this method was promising because of no need for any equipment, high specificity, enough sensitivity, low cost and rapidity (less than 30 min) to complete after genomic DNA extraction.
“…This method is relatively inexpensive and fast and, at the same time, based on a portable and cost-effective device. In recent years, LAMP has been applied in the diagnosis of other parasitic diseases, such as malaria, trypanosomiasis, schistosomiasis, or leishmaniasis [ 91 , 92 , 93 , 94 ].…”
Section: Diagnostics Of Toxoplasmosis In Hiv-infected Patientsmentioning
Toxoplasma gondii is a worldwide distributed protozoan parasite. This apicomplexan parasite infects one-third of the population worldwide, causing toxoplasmosis, considered one of the neglected parasitic infections. In healthy humans, most infections are asymptomatic. However, in immunocompromised patients, the course of the disease can be life-threatening. Human immunodeficiency virus (HIV)-infected patients have a very high burden of Toxoplasma gondii co-infection. Thus, it is essential to use modern, sensitive, and specific methods to properly monitor the course of toxoplasmosis in immunodeficient patients.
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