Early Diagnosis Of Tuberculosis Research Articles

Toward the early diagnosis of tuberculosis: A gold particle-decorated graphene-modified paper-based electrochemical biosensor for Hsp16.3 detection

Tuberculosis (TB) currently remains a major life-threatening disease as it can be fatal if not treated properly or in a timely manner. Herein, we first describe a disposable and cost-effective paper-based electrochemical biosensor based on a gold particle-decorated carboxyl graphene (AuPs/GCOOH)-modified electrode for detecting heat shock protein (Hsp16.3), which is a specific biomarker indicating the onset of TB infection. The device pattern was first engineered to facilitate detection procedures and printed on low-cost filter paper to create hydrophobic and hydrophilic regions using a wax printing technique. Immunoassays proceeded in a half-sandwich format because it is a reagent-less approach and requires no labeling step. The fabrication of the immunosensor began with GCOOH drop casting, the electrochemical deposition of AuPs, and the establishment of a biorecognition layer against Hsp16.3 utilizing 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC)/N-hydroxysuccinimide (NHS)-sulfo standard chemistry. The appearance of Hsp16.3 resulted in a substantial decrease in the electrochemical signal response of the redox probe employed [Fe (CN)6]3−/4− due to the created immunocomplexes that possess insulation properties. GCOOH enables direct antibody immobilization, and AuPs enhance the electrochemical properties of the sensor. This proposed immunosensor, while requiring only a miniscule sample volume (5 μL), achieved superior performance in terms of the limit of detection, measuring at 0.01 ng/mL. Our platform was confirmed to be highly specific to Hsp16.3 and can rapidly detect TB-infected sera without necessitating any pre-enrichment (20 min), making it an alternative and particularly suitable for the early diagnosis of TB in resource-scarce countries.

CARTRIDGE-BASED NUCLEIC ACID AMPLIFICATION TEST, AN IMPORTANT DIAGNOSTIC TOOL FOR TUBERCULOSIS BOTH PULMONARY AND EXTRA-PULMONARY TUBERCULOSIS

Background and Aims: Tuberculosis (TB) is severe infectious disease caused by Mycobacterium tuberculosis and imposes significant morbidity and mortality. Early diagnosis of active TB forms pulmonary and extrapulmonary is very important and the diagnostic methods such as culture test and Ziehl-Neelsen (ZN) stain displayed low diagnostic accuracy. Cartridge-based nucleic acid amplification test (CBNAAT) is widely used for the diagnosis of TB with good accuracy rate. Hence, the current study was commenced to assess the diagnostic usefulness of CBNAAT for the diagnosis of mycobacterium TB (MTB) and compared with ZN staining. Methods: This was a prospective study conducted on 250 sputum samples of pulmonary TB (new cases) and also patients who were receiving the treatment for TB. 5 mL of sputum sample including CSF, pericardial or ascitic fluid, pus, or lymph nodes aspirates were collected and subjected to ZN staining and CBNAAT. Results: Mean age observed was 48.12±8.76 years. 30 (12%) showed smear positive and 220 (88%) were smear negative for ZN staining. Further, samples have been subjected to CBNAAT showed 60 (24%) MTB positive, and 190 (74%) showed MTB negative. CBNAAT showed sensitivity and specificity of 91.5% and 89%. Out of 60 positives for MTB by CBNAAT, MTB has been identified in 28 patients. Conclusion: CBNAAT is a great tool in the early diagnosis of pulmonary and extrapulmonary TB.

Tuberculosis revisted: classic imaging findings in childhood

Tuberculosis (TB) remains one of the major public health threats worldwide, despite improved diagnostic and therapeutic methods. Tuberculosis is one of the main causes of infectious disease in the chest and is associated with substantial morbidity and mortality in paediatric populations, particularly in low- and middle-income countries. Due to the difficulty in obtaining microbiological confirmation of pulmonary TB in children, diagnosis often relies on a combination of clinical and radiological findings. The early diagnosis of central nervous system TB is challenging with presumptive diagnosis heavily reliant on imaging. Brain infection can present as a diffuse exudative basal leptomeningitis or as localised disease (tuberculoma, abscess, cerebritis). Spinal TB may present as radiculomyelitis, spinal tuberculoma or abscess or epidural phlegmon. Musculoskeletal manifestation accounts for 10% of extrapulmonary presentations but is easily overlooked with its insidious clinical course and non-specific imaging findings. Common musculoskeletal manifestations of TB include spondylitis, arthritis and osteomyelitis, while tenosynovitis and bursitis are less common. Abdominal TB presents with a triad of pain, fever and weight loss. Abdominal TB may occur in various forms, as tuberculous lymphadenopathy or peritoneal, gastrointestinal or visceral TB. Chest radiographs should be performed, as approximately 15% to 25% of children with abdominal TB have concomitant pulmonary infection. Urogenital TB is rare in children. This article will review the classic radiological findings in childhood TB in each of the major systems in order of clinical prevalence, namely chest, central nervous system, spine, musculoskeletal, abdomen and genitourinary system.Graphical

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According to WHO, the frequency of infertility in different countries varies widely and has no tendency to decrease. Taking into account the fact that the structure and frequency of infertile marriage in all countries is determined by application, which does not provide clear data about the real picture of infertility in a given country, countries are recommended to conduct epidemiological studies within the framework of the human reproduction program, that would allow determining the incidence of infertility in a given country, causal structure, contributing factors, existing experience and methods of research and treatment of couples suffering from infertility, effectiveness of research and treatment to develop and implement national strategies and programs to overcome the problem of infertility. Therefore, for the diagnosis, treatment and overcoming of infertility, it is very important to study its causality and prevalence. Tuberculosis of the reproductive system is neglected as a causal factor in most cases and they come to this only after denying the rest of infectious and non-infectious diseases. However, studying the morphofunctional features of tuberculosis, we are convinced that unlike many other causal factors, they are irreversible in this case. Therefore, early diagnosis of tuberculosis is the key to infertility treatment. And tuberculosis prevention, in addition to medical problems and approaches, should also have a social component that prevents poverty, possible malnutrition, unemployment and emigration.

Expedited diagnosis of pediatric tuberculosis using Truenat MTB-Rif Dx and GeneXpert MTB/RIF

Rapid, cost-effective, and sensitive diagnostic assays are essential for global tuberculosis (TB) control, especially in high TB burden, resource-limited settings. The current study was designed to evaluate diagnostic accuracy of Truenat MTB-Rif Dx (MolBio) in children less than 18 years of age, with symptoms suggestive of TB. Gastric aspirate, induced sputum, and broncho-alveolar lavage samples were subjected simultaneously to AFB-smear, GeneXpert MTB/RIF, liquid culture (MGIT-960) and Truenat MTB-Rif Dx. The index-test results were evaluated against microbiological reference standards (MRS). Truenat MTB-Rif Dx had a sensitivity of 57.1%, specificity of 92% against MRS. The sensitivity and specificity of the Truenat MTB-RIF Dx compared with liquid culture was 58.7% and 87.5% while GeneXpert MTB/RIF was 56% and 91.4%. The performance of both GeneXpert MTB/RIF and Truenat MTB-Rif Dx are comparable. Result of our study demonstrates that Truenat MTB-Rif can aid in early and efficient diagnosis of TB in children.

Ferritin as proinflamatory biomarker of iron metabolism in tuberculosis patients (review)

Traditional methods of tuberculosis (TB) diagnosis, including sputum microscopy and culture for Mycobacterium tuberculosis detection, are time-consuming or have unsatisfactory sensitivity. However, early diagnosis of TB with high accuracy and sensitivity is very important for disease outcomes and prevention. Therefore, there is an urgent need for new TB diagnostic methods based on TB-associated biomarkers, with rapid availability of results that do not require sputum analysis, are inexpensive, and have high sensitivity and specificity. Objective — to study the mechanisms of ferritin participation in the pathogenesis of tuberculosis basing on the literature data. Materials and methods. 242 literature sources were found in the PubMed system by the query «Ferritin AND Tuberculosis» and 40 of them were selected for further detailed study. Results and discussion. Studies have shown that serum iron and transferrin concentrations are lower and ferritin levels are higher in patients with TB compared to those without TB. These deviations in the concentration of ferritin and transferrin usually normalize after treatment. Lower transferrin levels are associated with both early and late TB progression, and higher ferritin and hepcidin levels are associated with a higher risk of early TB progression in TB contacts. In addition, the status of biomarkers of iron metabolism can be used as an indicator of treatment failure (low ferritin) and mortality (high ferritin). Finally, low levels of transferrin and serum iron, as well as high ferritin concentrations in HIV-infected patients predict an increased risk of TB disease and relapse. Conclusions. Iron metabolism between M. tuberculosis and the host organism is closely related and plays an important role in the pathogenesis of tuberculosis. Parameters of iron metabolism are promising markers of both the course and effectiveness of tuberculosis treatment. In particular, changes in the level of ferritin can be predictors of both the ineffectiveness of tuberculosis treatment and mortality from this disease, so the prognostic value of this marker requires further detailed study.

Reduced Graphene Oxide-Polydopamine-Gold Nanoparticles: A Ternary Nanocomposite-Based Electrochemical Genosensor for Rapid and Early Mycobacterium tuberculosis Detection.

Tuberculosis (TB) has been a devastating human illness for thousands of years. According to the WHO, around 10.4 million new cases of tuberculosis are identified every year, with 1.8 million deaths. To reduce these statistics and the mortality rate, an early and accurate TB diagnosis is essential. This study offers a highly sensitive and selective electrochemical biosensor for Mycobacterium tuberculosis (MTB) detection based on a ternary nanocomposite of reduced graphene oxide, polydopamine, and gold nanoparticles (rGO-PDA-AuNP). Avidin-biotin coupling was used to bind the MTB probe DNA onto the rGO-PDA-AuNP modified glassy carbon electrode (ssDNA/avidin/rGO-PDA-AuNP). UV-Visible, Raman, XRD, and TEM were used to evaluate the structural and morphological characteristics of rGO-PDA-AuNP. Furthermore, DNA immobilization is validated using FESEM and FT-IR techniques. The modified electrodes were electrochemically analyzed using cyclic voltammetry (CV) and linear sweep voltammetry (LSV), and the results indicate that the produced electrode can detect target DNA up to 0.1 × 10-7 mM with 2.12 × 10-3 mA µM-1 sensitivity and a response time of 5 s. The constructed genosensor displayed high sensitivity and stability, and it also provides a unique strategy for diagnosing MTB at an early stage. Furthermore, our rGO-PDA-AuNP/GCE-based electrochemical platform has broad potential for creating biosensor systems for detecting various infectious pathogens and therapeutically significant biomarkers.

Diagnostic Dilemma of Chest Wall Tuberculosis Masquerading Breast Lump and Sarcoma

Chest wall tuberculosis (TB) is rare and can often masquerade as a tumour. Diagnostic confirmation is made by bacteriological findings of acid-fast bacilli and culture of Mycobacterium tuberculosis or histopathological findings. This is a 37-year-old immunocompetent lady who presented with a 3-month history of gradually increasing right breast lump with suspicious characteristics during clinical examinations. Ultrasound of the breast showed normal breast tissue with a well-defined hypoechoic lesion within the anterior inferior pectoralis muscle. CT scan of the thorax revealed a right anterior chest wall lesion with multiple lung nodules and consolidations. Thus, there was a high suspicion of chest wall tumour and an initial diagnosis of soft tissue sarcoma was made. Biopsy of the lesion showed necrotising granulomatous inflammation but no acid-fast bacilli. A revised diagnosis of chest wall tuberculosis was made. She attended follow-up complaining of shortness of breath and pleuritic chest pain with signs of right pleural effusion. Her symptoms improved after the initiation of anti-TB treatment. This case demonstrated the challenge in making an early diagnosis of chest wall TB and commencement of anti-TB treatment.

Detection of Mycobacterium tuberculosis Complex in Sputum Samples Using Droplet Digital PCR Targeting mpt64.

Tuberculosis (TB) is one of the top 10 causes of death worldwide. It is challenging to find methods of diagnosis of active pulmonary TB that are sensitive enough to detect cases for proper treatment before unintentional transmission. Droplet digital PCR (ddPCR) is a highly sensitive method to detect genetic material of pathogens, but it has rarely been used for diagnosis of TB. This study compared the sensitivity of ddPCR with that of GeneXpert and AFB smear microscopy in 180 leftover sputum samples from patients suspected of having TB on the basis of clinical symptoms and radiography. Absolute quantification of copy numbers of MTB-specific genes was possible using ddPCR targeting the mpt64 gene. Among the 180 samples, 41.1% were diagnosed as having TB using ddPCR. The sensitivities of AFB smear microscopy, GeneXpert and ddPCR were 41.9%, 82.4% and 100%, respectively. AFB smear microscopy and GeneXpert both had a specificity of 100%, and the specificity of ddPCR was 95.3%. The accuracy of ddPCR (97.2%) is higher than that of GeneXpert (92.7%). This robust ddPCR system could potentially be used as a method for early diagnosis of TB.

Immunological depiction of synthetic B-cell epitopes of Mycobacterium tuberculosis.

To combat the tuberculosis (TB) epidemic, the development of a better and faster diagnosis or more effective vaccine is essential. Pulmonary TB (PTB) is one of the major causes of morbidity and mortality. Early diagnosis of TB is difficult. Serological assays have been performed with several antigens of laboratory strains such as Mycobacterium tuberculosis H37Rv which have not been found to be highly sensitive. In the present study, various peptides were synthesized which were predicted on the basis of immunoreactivity and differential expression in clinical isolates of M. tuberculosis compared to their expression in a laboratory strain of M. tuberculosis. Therefore, the aim of this study was to compare the antibody levels in PTB and healthy controls against these peptides. An effort was made to evaluate antibody response to peptides derived from proteins Rv2588c, Rv0512, Rv0148, Rv0896, and Rv0635 of M. tuberculosis in PTB patients and healthy individuals through enzyme-linked immunosorbent assay. Five milliliters of venous blood samples was collected from each participant, and serum was separated and stored until use. Antibody levels against these peptides, Rv2588c, Rv0512, Rv0148, Rv0896. and Rv0635 in 139 PTB patients and 52 healthy controls were evaluated. Higher immune response was observed in PTB patients when compared with healthy individuals. Strong immunoglobulin G responses with high percentage, considerable difference among patients and healthy controls was observed with P < 0.0001. In our study, we found significant statistical differences in antibody levels in PTB patients and healthy individuals against these peptides. These peptides are suggestive of being a potential new candidate (s) for early diagnosis of TB.

An Improved Densenet Deep Neural Network Model for Tuberculosis Detection Using Chest X-Ray Images

Tuberculosis (TB) is a highly contagious and life-threatening infectious disease that affects millions of people worldwide. Early diagnosis of TB is essential for prompt treatment and control of the spread of the disease. In this paper, a new deep learning model called CBAMWDnet is proposed for the detection of TB in chest X-ray (CXR) images. The model is based on the Convolutional Block Attention Module (CBAM) and the Wide Dense Net (WDnet) architecture, which has been designed to effectively capture spatial and contextual information in the images. The performance of the proposed model is evaluated based on a large dataset of chest X-ray images and it is compared to several state-of-the-art models. The results show that the proposed model outperforms the other models in terms of accuracy (98.80%), sensitivity (94.28%), precision (98.50%), specificity (95.7%) and F1 score (96.35%). Additionally, our model demonstrates excellent generalization ability, with consistent performance on different datasets. In conclusion, the proposed CBAMWDnet model is a promising tool for the early diagnosis of TB, with superior performance compared to other state-of-the-art models, as evidenced by the evaluation metrics of accuracy, sensitivity, and specificity.

Usage of artificial intelligence tools in community-level X-ray triaging for tuberculosis in Chennai, Tamil Nadu

Background: The end tuberculosis (TB) strategy emphasises early and correct diagnosis of TB. Chest X-ray (CXR) is an essential tool for triaging and screening TB and confirming the diagnosis in fewer situations. Greater Chennai Corporation (GCC) implemented Mobile Diagnostic Units (MDUs) retrofitted with X-rays with artificial intelligence (AI). Objectives: The study’s objectives were to determine the X-ray triaging performance in MDU vans using AI tools in GCC, Tamil Nadu. Materials and Methods: AI is to increase access to quality TB screening diagnostics in high-risk locations. Genki AI-powered Public Health Screening Solution from Deeptek used for TB triaging after uploading CXR images from MDU. X-ray has been uploaded in AI software once taken, and the results were available immediately after uploading. The radiologist reports helped to take further courses of action. Results: A total of 79,462 CXR was taken from April 2019 to April 2022 from 7 MDU vans. Amongst 3.4% were identified as suggestive of TB, 1.4% old TB, 0.89% COVID (from 2020) and 7.2% other chest abnormalities. The sensitivity of CXR-AI was 0.98 (95% confidence interval [CI]: 0.97, 0.98), and the specificity was 0.96 (95% CI: 0.96, 0.97). Conclusion: AI helps in faster triage for further public health action and eliminates the challenges of the availability of functional X-rays, interpretation and reporting.

Utility of laboratory diagnostic tests in women suspected of genital tuberculosis attending a tertiary care teaching hospital.

Genital Tuberculosis is a form of extrapulmonary tuberculosis, which if not diagnosed early can lead to complications. The objective of this study was to determine the sensitivity and specificity of Xpert Mycobacterium tuberculosis/rifampin (MTB/RIF) assay in genital tuberculosis (TB) in comparison with culture as a gold standard. The results of the Xpert MTB/RIF assay performed from January 2020 to August 2021 were compared with the results of culture by Mycobacterium Growth Indicator Tube (MGIT) 960. Out of 75 specimens, fluorescent microscopy and liquid culture using MGIT and Xpert assay were positive in 3 (4%), 21 (28%), and 14 (18%), respectively. The sensitivity and specificity of the Xpert MTB/RIF assay were 66.67% and 100%. All smear-positive specimens were positive by culture and Xpert assay. Three specimens were positive by all the tests, i.e., microscopy, culture, and Xpert assay. Fifty-four specimens were negative by microscopy, culture, and Xpert assay. Discordance between the results of culture and Xpert assay was observed in seven specimens which were culture positive and Xpert assay negative. Three (21.42%) out of 21 culture-positive specimens showed monoresistance to rifampicin by Xpert MTB/RIF assay and culture drug susceptibility testing. Xpert MTB/RIF assay showed good sensitivity and specificity compared to liquid culture in genital TB. This test is easy to perform, provides results in 2 h, and can also detect rifampicin resistance, which is a surrogate marker for multidrug-resistant TB. Hence, the Xpert assay can be used under the National TB Elimination Program for early and rapid diagnosis of TB in endometrial specimens to prevent complications like infertility.

Active Case Finding for Tuberculosis among Health Care Workers in a Teaching Hospital, Puducherry, India.

Health care workers (HCWs) are at risk of acquiring tuberculosis (TB) infection and disease due to occupational exposure. But there are no national guidelines on routine screening for TB (active case finding (ACF)) among HCWs and understand its implementation and feasibility. This study was conducted among HCWs in a teaching hospital in India. We used symptom screening to identify those with presumptive TB and were further evaluated for diagnosis of TB. A total of 1,001 HCWs were screened over a period of 18 months. In our study, 51 (5.1%) HCWs were found to have presumptive TB and on further evaluation, 5 (0.5%) of these patients were diagnosed with active TB. The number needed to screen (NNS) for one active TB among the HCWs was 200. Alcohol use was significantly associated with both presumptive TB (P = 0.037) and active TB (P = 0.035) among HCWs, and exposure to active TB patients (P = 0.014) in the family and workplace and increased frequency of exposures (P = <0.001) were associated with presumptive TB. ACF for TB among HCWs had a good yield in our study. ACF utilizing routine national TB program guidelines is feasible to be implemented among HCWs to aid in the early diagnosis and treatment of TB in this high-risk group.

Early detection of tuberculosis using hybrid feature descriptors and deep learning network.

To detect tuberculosis (TB) at an early stage by analyzing chest X-ray images using a deep neural network, and to evaluate the efficacy of proposed model by comparing it with existing studies. For the study, an open-source X-ray images were used. Dataset consisted of two types of images, i.e., standard and tuberculosis. Total number of images in the dataset was 4,200, among which, 3,500 were normal chest X-rays, and the remaining 700 X-ray images were of tuberculosis patients. The study proposed and simulated a deep learning prediction model for early TB diagnosis by combining deep features with hand-engineered features. Gabor filter and Canny edge detection method were applied to enhance the performance and reduce computation cost. The proposed model simulated two scenarios: without filter and edge detection techniques and only a pre-trained model with automatic feature extraction, and filter and edge detection techniques. The results achieved from both the models were 95.7% and 97.9%, respectively. The proposed study can assist in the detection if a radiologist is not available. Also, the model was tested with real-time images to examine the efficacy, and was better than other available models.

Comparison of Genexpert MTB/RIF Assay and AFB Smear Microscopy in Diagnosis of Pulmonary Tuberculosis among HIV Patients at a Tertiary Care Hospital

Introduction: Tuberculosis (TB) has been the most common acute opportunistic infection in HIV positive patients and accounts for more than half of all AIDS cases in underdeveloped nations. Hence, rapid laboratory diagnosis of M. tuberculosis is needed for vulnerable patients. Methodology: In this study, 72 sputum samples were collected from ART-naive and patients using ART for 6 months. The samples were tested with the GeneXpert MTB / RIF assay to diagnose TB and drug resistance and AFB smear microscopy as per NTP guidelines. Results: Among 72 sputum samples studied, males were more diagnosed with TB than females. People aged 25-56 years were more infected with HIV-TB co-infection. Four patients (5.56%) were found to be TB positive with both techniques, 7 (9.72%) were GeneXpert MTB/RIF positive but smear-negative and 61 patients (84.72%) were negative with both methods. The positivity for MTB detected for GeneXpert MTB/RIF method in females was 3 (15%) and the males were 8 (15.38%), while for the ZN staining method the positivity in females was 2 (10%) and the males were 2 (3.85%). The GeneXpert MTB/RIF assay was also capable of detecting TB in smear-negative cases. Conclusion: This study showed that the GeneXpert MTB/RIF assay is an effective tool for the early diagnosis of TB among HIV patients as compared to AFB smear staining method.

THE MOLECULAR STUDY OF LncRNA “NEAT2” FOR EARLY DIAGNOSIS OF TB IN POPULATION OF MADHYA PRADESH

One of the deadliest infectious diseases in the world is tuberculosis (TB), a chronic disease brought on by the bacteria Mycobacterium tuberculosis. There is still no viable method for early screening, despite substantial advancements in tuberculosis detection methods and therapeutic strategies. Different cellular processes can hinder the growth of TB due to dysregulation of gene expression patterns connected to particular substances. Long non-coding RNAs (lncRNAs) are molecules that have been found to control the expression of protein-coding genes and take part in processes like cell cycle control, gene silencing, and cellular differentiation. It has been discovered that dysregulation of lncRNAs is linked to a variety of illnesses, including cancer and infectious diseases. Therefore, it is encouraging that lncRNAs have been identified as potential molecular indicators and therapeutic targets for tuberculosis. In present study. Human blood samples from the TB patients and healthy individuals from Sidhi District of Madhya Pradesh were collected. Total RNA were extracted from blood samples of using TRIzol Reagent (Takara) according to the manufacturer’s protocol. cDNA were prepared using synthesis kit (Biorad), In the present investigation gene expression of LncRNA “NEAT2” and IFNG were assessed in WBCs of TB Patients and Healthy individuals, using Real Time PCR technique. This study reported Lnc RNA NEAT2 up-regulation, which reflect significant involvement of this LncRNA in pathogenesis of TB and it may be one of the potential marker for the early diagnosis of TB.

Host biomarker-based quantitative rapid tests for detection and treatment monitoring of tuberculosis and COVID-19

Diagnostic services for tuberculosis (TB) are not sufficiently accessible in low-resource settings, where most cases occur, which was aggravated by the COVID-19 pandemic. Early diagnosis of pulmonary TB can reduce transmission. Current TB-diagnostics rely on detection of Mycobacterium tuberculosis (Mtb) in sputum requiring costly, time-consuming methods, and trained staff. In this study, quantitative lateral flow (LF) assays were used to measure levels of seven host proteins in sera from pre-COVID-19 TB-patients diagnosed in Europe and latently Mtb-infected individuals (LTBI), and from COVID-19 patients and healthy controls. Analysis of host proteins showed significantly lower levels in LTBI versus TB (AUC:0·94) and discriminated healthy individuals from COVID-19 patients (0·99) and severe COVID-19 from TB. Importantly, these host proteins allowed treatment monitoring of both respiratory diseases. This study demonstrates the potential of non-sputum LF assays as adjunct diagnostics and treatment monitoring for COVID-19 and TB based on quantitative detection of multiple host biomarkers.

Implementing molecular tuberculosis diagnostic methods in limited-resource and high-burden countries.

Tuberculosis (TB) is one of the deadliest infectious diseases in the world with more than a million people dying of TB each year. Accurate and timely TB diagnosis has the potential to alleviate the global TB burden; therefore, one of the pillars of the End TB Strategy developed by the World Health Organization (WHO) is the early diagnosis of TB, including universal drug-susceptibility testing (DST). The WHO emphasises the importance of DST before treatment initiation, using molecular WHO-recommended rapid diagnostic tests (mWRDs). Currently available mWRDs are nucleic acid amplification tests, line probe assays, whole genome sequencing, and targeted next-generation sequencing. However, implementing the sequencing mWRDs in routine laboratories in low-income countries is constrained by the existing infrastructure, high cost, the specialised skills needed, data storage, and the current delay in results compared with other routine methods. These limitations are pronounced in resource-limited settings, which often have a high TB burden and need for innovative TB diagnostic technologies. In this article we propose several possible solutions, like adapting infrastructure capacity to needs, advocating for lowering costs, building bioinformatics and laboratory capacity, and increasing the use of open-access resources for software and publications.

Multiple signal amplification and selective recognition reactions-assisted homogeneous binary visual aptasensor of tuberculosis interferon γ in clinical samples

Interferon-γ (IFN-γ) analysis is critical for tuberculosis (TB) diagnosis. However, the existing conventional immunoassay methods are less sensitive and laborious. We describe cadmium telluride quantum dots (CdTe QDs) and calcein-based binary visual and fluorescence homogeneous aptamer sensing strategy for IFN-γ analysis. This strategy integrates enzyme-free catalytic hairpin assembly (CHA) amplification, selective recognition properties of QDs and calcein for Ag+ and C-Ag+-C structures, and ink-jet printing technology for making test strips. Using QDs- and calcein-based fluorescence modes, respectively, IFN-γ with limits of detection (LODs) as low as 0.3 ag/mL and 0.25 ag/mL were obtained at optimum conditions. Color and distance reading modes enabled the analysis of 100 ag/mL IFN-γ with naked eyes. Quantitative findings of IFN-γ analysis in 51 clinical plasma samples using dual fluorescence modes were in line with those obtained by enzyme-linked immunosorbent assay (ELISA), sputum culture, polymerase chain reaction (PCR), Xpert MTB/rifampin (RIF) and computed tomography (CT). Additionally, findings from IFN-γ analysis in 12 clinical samples obtained using QDs- and calcein-based distance reading strips were highly consistent with those of ELISA. Therefore, our analytical system may provide an additional and more sensitive tool for early diagnosis of TB.