Tuberculosis diagnostics: overcoming ancient challenges with modern solutions

Diagnostic utility of microRNA profiles in cavitatory and non-cavitatory pulmonary tuberculosis: Research protocol

BACKGROUND

Tuberculosis (TB) is a common infection causing huge morbidity and mortality to mankind. The analytical methods used in diagnosing TB are not sensitive in paucibacillary infections and also require trained technical personnel. MicroRNAs are stable in serum and other body fluids, and hold great potential in the diagnosis of TB.

AIM

To analyze the dysregulated microRNA profiles among patients with cavitatory and non-cavitatory pulmonary TB.

METHODS

The prospective study will be conducted in a tertiary care center in India. Adult patients with newly diagnosed pulmonary TB will be included. There will be two groups: Patients with sputum positive pulmonary TB with cavity and without cavity (group1), and apparently healthy individuals (group 2). The participants will undergo sputum examination, Xpert Mycobacterium TB complex/resistance to rifampin (Mtb/RIF) assay, chest X-ray, and blood investigations and serum microRNA detection. Ethics approval has been obtained. Written informed consent will be obtained. Appropriate statistical analyses will be used.

RESULTS

MicroRNAs will be correlated with sputum positivity, Xpert Mtb/RIF assay, radiological involvement, inflammatory markers, and course of the disease among cases and controls.

CONCLUSION

MicroRNAs could serve as potential diagnostic biomarkers in diagnostically challenging TB patients.

Applicability of TB-LAMP test for diagnosis of pulmonary TB among HIV-positive individuals

BACKGROUND

The loop-mediated isothermal amplification for TB (TB-LAMP) assay is more cost-effective and accessible than the Xpert® MTB/RIF assay. This study aimed to evaluate the diagnostic performance of the TB-LAMP assay in individuals with and without HIV infection.

METHODS

Patients aged ≥15 years presenting with symptoms of TB were included in the study. The TB-LAMP assay was performed alongside routine TB diagnostic methods, including the Xpert assay and smear microscopy, to evaluate discrepancies in test results and associated factors.

RESULTS

A total of 903 patients were enrolled in the study. The positive percentage agreement for smear microscopy and TB-LAMP compared with the Xpert assay was respectively 54.3% (95% CI 46.6-61.8) and 76.6% (95% CI 69.9-82.6). Among HIV-positive individuals, the positive percentage agreement was 42.5% (95% CI 32.9-52.4) for smear microscopy and 68.9% (95% CI 59.1-77.5) for TB-LAMP. Factors such as age >60 years (adjusted OR 3.29, 95% CI 0.32-33.83), loss of appetite (aOR 0.30, 95% CI 0.13-0.70), and HIV-positive status (aOR 3.29, 95% CI 1.12-9.63) were associated with discrepancies between TB-LAMP and Xpert results.

CONCLUSIONS

TB-LAMP demonstrated better agreement with the Xpert assay compared with smear microscopy in detecting TB among HIV-positive patients, suggesting that TB-LAMP could effectively replace smear microscopy.

Decoding differentially expressed genes to identify potential immunity associated biomarkers in Tuberculosis: An integrative bioinformatics approach

Tuberculosis (TB) poses a significant threat to the Indian population, with India accounting for 20 % of the global TB cases. The current study aims to identify molecular biomarkers for better diagnostics by comparing the transcriptome signatures of healthy individuals against TB-affected individuals. Next-generation sequencing (NGS) tools were used to identify critical differentially expressed genes (DEGs). 302 DEGs were identified based on a logFC threshold of |3| and adjusted p-value < 0.05. STRING database was used to plot the interactions amongst the 302 DEGs. The DEGs were functionally annotated, highlighting numerous physiological functions affected due to the dysregulation of the identified hub genes. TLR4, FCGR1A, ITGAM, LTF, and CXCR2 were the hub genes identified and observed to dysregulate crucial physiological functions. TLR4 has been implicated in the progression of TB in various populations, and the findings of this study will enable researchers to improve the current landscape of diagnostics for TB.

Association Between Pulmonary Tuberculosis and Bronchial Anthracosis

Introduction Anthracosis is black discoloration of the bronchi, which can sometimes cause anthracofibrosis. Usually, exposure to biomass fuel, air pollution, or smoke at the workplace causes it. The objective of the current study was to determine the association between tuberculosis and anthracosis. Methods Patients with chronic dyspnea, dry cough, and infiltrates or mass lesions on chest X-rays underwent bronchoscopic lavage and biopsy where needed. Patients were divided into two groups on the basis of anthracosis on bronchoscopy. Diagnosis of tuberculosis was made on bronchial wash acid-fast bacilli smear, mycobacterial culture, or Xpert Mycobacterium tuberculosis (MTB) rifampicin (RIF) assay. Results Tuberculosis was diagnosed by bronchoscopy in 68/173 (39.30%) patients with anthracosis which was significantly higher (p-value 0.020) than the control group (43/159, 27.04%). Most of the cases (54/68, 79.41%) had positive Xpert assay. The male-to-female ratio was 3:1, and all the females with anthracosis were homemakers and used biomass fuel. Conclusion Patients with exposure to smoke are prone to develop anthracosis. The presence of anthracosis is associated with the development of tuberculosis. Appropriate investigations for tuberculosis must be done in subjects undergoing bronchoscopy who are found to have anthracosis. Expanding understanding among the masses regarding the hazards of using biomass fuel in closed spaces can be a crucial measure toward diminishing the chance of developing anthracosis and the concomitant risk of tuberculosis.

Advancing against drug-resistant tuberculosis: an extensive review, novel strategies and patent landscape

Drug-resistant tuberculosis (DR-TB) represents a pressing global health issue, leading to heightened morbidity and mortality. Despite extensive research efforts, the escalation of DR-TB cases underscores the urgent need for enhanced prevention, diagnosis, and treatment strategies. This review delves deep into the molecular and genetic origins of different types of DR-TB, highlighting recent breakthroughs in detection and diagnosis, including Rapid Diagnostic Tests like Xpert Ultra, Whole Genome Sequencing, and AI-based tools along with latest viewpoints on diagnosis and treatment of DR-TB utilizing newer and repurposed drug molecules. Special emphasis is given to the pivotal role of novel drugs and discusses updated treatment regimens endorsed by governing bodies, alongside innovative personalized drug-delivery systems such as nano-carriers, along with an analysis of relevant patents in this area. All the compiled information highlights the inherent challenges of current DR-TB treatments, discussing their complexity, potential side effects, and the socioeconomic strain they impose, particularly in under-resourced regions, emphasizing the cost-effective and accessible solutions. By offering insights, this review aims to serve as a compass for researchers, healthcare practitioners, and policymakers, emphasizing the critical need for ongoing R&D to improve treatments and broaden access to crucial TB interventions.

Research priorities and trends in pulmonary tuberculosis in Latin America: A bibliometric analysis

Tuberculosis (TB) poses a significant global public health challenge, particularly in developing countries. Over the years, scientific research has played a pivotal role in addressing this disease. In this study, we aimed to analyze and outline the trends in scientific output on TB and identify research priorities in Latin America (LA) from 1990 to 2021. Scientific production was analyzed, and the number of publications, financing sources, and journal characteristics were evaluated. Collaboration networks and keywords were visualized using mapping analysis with VOSviewer software. Research themes were prioritized by country based on co-occurrence frequency. In total, 4399 documents were identified, a significant trend was evident in the number of publications per year (R2 = 0.981), and research substantially contributed to the reduction of TB-related mortality (R2 = -0.876). Most publications were original articles (83.8 %). The International Journal of Tuberculosis and Lung Disease had the highest publication and citation rates per document. International collaboration was predominantly with the United States, France, and Canada. Brazil, Argentina, and Mexico had the highest number of publications and external collaborations. In LA, interest in researching studies related to treatment and diagnosis (32.5 %) was notably high, followed by epidemiology and screening (26.9 %). Among the 20 countries in LA, research priorities varied, with the highest emphasis on HIV/AIDS (14/20), epidemiology (9/20), anti-TB agents (6/20), and mortality (5/20). TB resistance was only considered a research priority in Brazil, Peru, and Haiti. Therefore, LA experienced significant growth in its scientific output, playing a crucial role in TB control. Strategic adaptation to the region's specific challenges was observed, particularly in HIV/AIDS coinfection, epidemiological studies, and drug resistance. This progress was achieved by outstanding international scientific collaboration. This holistic approach emphasizes the importance of research in the fight against TB in LA.

Recombinant YopE and LcrV vaccine candidates protect mice against plague and yersiniosis

No licensed vaccine exists for the lethal plague and yersiniosis. Therefore, a combination of recombinant YopE and LcrV antigens of Yersinia pestis was evaluated for its vaccine potential in a mouse model. YopE and LcrV in formulation with alum imparted a robust humoral immune response, with isotyping profiles leaning towards the IgG1 and IgG2b subclasses. It was also observed that a significantly enhanced expression of IFN-γ, TNF-α, IL-6, IL-2, and IL-1β from the splenic cells of vaccinated mice, as well as YopE and LcrV-explicit IFN-γ eliciting T-cells. The cocktail of YopE + LcrV formulation conferred complete protection against 100 LD50Y. pestis infection, while individually, LcrV and YopE provided 80 % and 60 % protection, respectively. Similarly, the YopE + LcrV vaccinated animal group had significantly lower colony forming unit (CFU) counts in the spleen and blood compared to the groups administered with YopE or LcrV alone when challenged with Yersinia pseudotuberculosis and Yersinia enterocolitica. Histopathologic evidence reinforces these results, indicating the YopE + LcrV formulation provided superior protection against acute lung injury as early as day 3 post-challenge. In conclusion, the alum-adjuvanted YopE + LcrV is a promising vaccine formulation, eliciting a robust antibody response including a milieu of pro-inflammatory cytokines and T-cell effector functions that contribute to the protective immunity against Yersinia infections. YopE and LcrV, conserved across all three human-pathogenic Yersinia species, provide cross-protection. Therefore, our current vaccine (YopE + LcrV) targets all three pathogens: Y. pestis, Y. pseudotuberculosis, and Y. enterocolitica. However, the efficacy should be tested in other higher mammalian models.

Mycobacterium tuberculosis latent infection in healthcare students: systematic review of prevalence

OBJECTIVE

The aim of this study was to synthesize the evidence on the prevalence of latent Mycobacterium tuberculosis infection (LTBI) among undergraduate health care students.

METHODS

A systematic review of prevalence with meta-analysis was conducted. Prospective and retrospective cohorts and cross-sectional studies involving probable exposure to M. tuberculosis during undergraduate education, along with the tuberculin skin test (TST) or interferon-γ release assay (IGRA) for investigation of latent tuberculosis were searched. Searches were conducted in MEDLINE, CINAHL, EMBASE, LILACS, Scopus, and Web of Science databases. Independent reviewers were responsible for the selection and inclusion of studies. Data were extracted, critically appraised, and synthesized using the JBI approach. PRISMA was used to report the study.

RESULTS

Twenty-two studies were analyzed. The overall prevalence in healthcare undergraduate students was 12.53%.

CONCLUSION

The prevalence of LTBI in undergraduate health students was high for such a highly educated population. Screening with TST and/or IGRA and chemoprophylaxis, when necessary, should be provided to undergraduate health students when in contact with respiratory symptomatic patients.

Hybrid use of Raman spectroscopy and artificial neural networks to discriminate Mycobacterium bovis BCG and other Mycobacteriales

Even in the face of the COVID-19 pandemic, Tuberculosis (TB) continues to be a major public health problem and the 2nd biggest infectious cause of death worldwide. There is, therefore, an urgent need to develop effective TB diagnostic methods, which are cheap, portable, sensitive and specific. Raman spectroscopy is a potential spectroscopic technique for this purpose, however, so far, research efforts have focused primarily on the characterisation of Mycobacterium tuberculosis and other Mycobacteria, neglecting bacteria within the microbiome and thus, failing to consider the bigger picture. It is paramount to characterise relevant Mycobacteriales and develop suitable analytical tools to discriminate them from each other. Herein, through the combined use of Raman spectroscopy and the self-optimising Kohonen index network and further multivariate tools, we have successfully undertaken the spectral analysis of Mycobacterium bovis BCG, Corynebacterium glutamicum and Rhodoccocus erythropolis. This has led to development of a useful tool set, which can readily discern spectral differences between these three closely related bacteria as well as generate a unique spectral barcode for each species. Further optimisation and refinement of the developed method will enable its application to other bacteria inhabiting the microbiome and ultimately lead to advanced diagnostic technologies, which can save many lives.

Diagnostic challenge of tuberculosis in systemic lupus erythematosus: a case report and literature review

Patients with systemic lupus erythematosus (SLE) are at increased risk of tuberculosis (TB) infection due to immune dysfunction and immunosuppressive therapy. We present a case study of a 40-year-old woman with systemic lupus erythematosus (SLE). Initially, she was diagnosed with a lupus flare based on her clinical symptoms and laboratory results. However, upon further investigation, positive polymerase-chain reaction results for M. tuberculosis in the cerebrospinal fluid and lung parenchymal changes on chest computed tomography scan were indicative of TB infection. There was initial uncertainty regarding whether TB had triggered a flare-up of SLE or if TB was merely mimicking the symptoms of a SLE flare-up. However, as increasing the prednisolone dose did not have a positive effect and the patient's condition improved significantly with anti-TB treatment alone, it became clearer that the deterioration observed upon admission was primarily due to TB progression rather than an SLE flare-up. Additionally, we review the current literature on TB and SLE, including risk factors, diagnostic challenges, and treatment considerations, highlighting the importance of considering TB infection in patients with SLE who present with overlapping manifestations. Prompt diagnosis and treatment are essential for improving outcomes in these patients.

Accessing Properties of Molecular Compounds Involved in Cellular Metabolic Processes with Electron Paramagnetic Resonance, Raman Spectroscopy, and Differential Scanning Calorimetry

In this work, we review some physical methods of macroscopic experiments, which have been recently argued to be promising for the acquisition of valuable characteristics of biomolecular structures and interactions. The methods we focused on are electron paramagnetic resonance spectroscopy, Raman spectroscopy, and differential scanning calorimetry. They were chosen since it can be shown that they are able to provide a mutually complementary picture of the composition of cellular envelopes (with special attention paid to mycobacteria), transitions between their molecular patterning, and the response to biologically active substances (reactive oxygen species and their antagonists-antioxidants-as considered in our case study).

Evolution of tuberculosis diagnostics: From molecular strategies to nanodiagnostics

Tuberculosis has remained a global concern for public health affecting the lives of people for ages. Approximately 10 million people are affected by the disease and 1.5 million succumb to the disease worldwide annually. The COVID-19 pandemic has highlighted the role of early diagnosis to win the battle against such infectious diseases. Thus, advancement in the diagnostic approaches to provide early detection forms the foundation to eradicate and manage contagious diseases like tuberculosis. The conventional diagnostic strategies include microscopic examination, chest X-ray and tuberculin skin test. The limitations associated with sensitivity and specificity of these tests demands for exploring new techniques like probe-based assays, CRISPR-Cas and microRNA detection. The aim of the current review is to envisage the correlation between both the conventional and the newer approaches to enhance the specificity and sensitivity. A significant emphasis has been placed upon nanodiagnostic approaches manipulating quantum dots, magnetic nanoparticles, and biosensors for accurate diagnosis of latent, active and drug-resistant TB. Additionally, we would like to ponder upon a reliable method that is cost-effective, reproducible, require minimal infrastructure and provide point-of-care to the patients.

Epidemiology of Tuberculosis Among People Living With HIV in the African Cohort Study From 2013 to 2021

BACKGROUND

The prevalence and incidence of tuberculosis (TB) is high among people living with HIV (PLWH) but is often underdiagnosed in HIV programmatic settings.

SETTING

President's Emergency Plan for AIDS Relief (PEPFAR)-supported research sites in Uganda, Kenya, Tanzania, and Nigeria.

METHODS

All patients underwent molecular testing at entry into a longitudinal cohort of PLWH and annually thereafter. We assessed the prevalence and incidence of TB and identified clinical and demographic factors associated with prevalent and incident TB using logistic regression and Cox proportional hazard models.

RESULTS

From 21 January, 2013, to 1 December 2021, 3171 PLWH were enrolled with a TB prevalence of 3% (n = 93). Of the cases with prevalent TB, 66% (n = 61) were bacteriologically confirmed. The adjusted odds of prevalent TB were significantly higher among those with higher educational attainment, PLWH for 1-5 years since their HIV diagnosis, those who were underweight, and those with CD4 counts <200 cells/mm 3 . The overall TB incidence rate was 600 per 100,000 person-years (95% CI: 481-748). We found that shorter time since HIV diagnosis, being underweight, taking antiretroviral therapy <6 months, and having a CD4 count <200 cells/mm 3 were significantly associated with incident TB. PLWH on dolutegravir/lamivudine/tenofovir had a 78% lower risk of incident TB compared with those on tenofovir/lamivudine/efavirenz (hazard ratio: 0.22; 95% CI: 0.08-0.63).

CONCLUSION

The prevalence and incidence of TB was notably high in this cohort sourced from PEPFAR clinics. Aggressive efforts to enhance HIV diagnosis and optimize treatment in programmatic settings are warranted to reduce the risk of HIV-TB co-occurrence in this cohort.

A Comparative Study on Visual Detection of Mycobacterium tuberculosis by Closed Tube Loop-Mediated Isothermal Amplification: Shedding Light on the Use of Eriochrome Black T

Loop-mediated isothermal amplification is a promising candidate for the rapid detection of Mycobacterium tuberculosis. However, the high potential for carry-over contamination is the main obstacle to its routine use. Here, a closed tube LAMP was intended for the visual detection of Mtb to compare turbidimetric and two more favorable colorimetric methods using calcein and hydroxy naphthol blue (HNB). Additionally, a less studied dye (i.e., eriochrome black T (EBT)) was optimized in detail in the reaction for the first time. Mtb purified DNA and 30 clinical specimens were used to respectively determine the analytical and diagnostic sensitivities of each method. The turbidimetric method resulted in the best analytical sensitivity (100 fg DNA/reaction), diagnostic sensitivity and specificity (100%), and time-to-positivity of the test (15 min). However, this method is highly prone to subjective error in reading the results. Moreover, HNB-, calcein-, and EBT-LAMP could respectively detect 100 fg, 1 pg, and 1 pg DNA/reaction (the analytical sensitivities) in 30, 15, and 30 min, while the diagnostic sensitivity and specificity were respectively 93.3% and 100% for them all. Interestingly, EBT-LAMP showed the lowest potential for subjective error in reading the results. This report helps judiciously choose the most appropriate visual method, taking a step forward toward the field applicability of LAMP for the detection of Mtb, particularly in resource-limited settings.

Improved Conventional and New Approaches in the Diagnosis of Tuberculosis

Tuberculosis (TB) is a life-threatening infectious disease caused by Mycobacterium tuberculosis (M. tuberculosis). Timely diagnosis and effective treatment are essential in the control of TB. Conventional smear microscopy still has low sensitivity and is unable to reveal the drug resistance of this bacterium. The traditional culture-based diagnosis is time-consuming, since usually the results are available after 3–4 weeks. Molecular biology methods fail to differentiate live from dead M. tuberculosis, while diagnostic immunology methods fail to distinguish active from latent TB. In view of these limitations of the existing detection techniques, in addition to the continuous emergence of multidrug-resistant and extensively drug-resistant TB, in recent years there has been an increase in the demand for simple, rapid, accurate and economical point-of-care approaches. This review describes the development, evaluation, and implementation of conventional diagnostic methods for TB and the rapid new approaches for the detection of M. tuberculosis.

Epidemiological Characteristics and Risk Factors Related to Drug-resistant Tuberculosis in Luanda, Angola

Tuberculosis (TB) is a major cause of illness and public health concern, especially in resource-limited countries. This study analyzed the characteristics related to anti-TB drug resistance. Moreover, we examined the evidence-based indications for the treatment of active TB in Angola. This study evaluated the medical records of 176 patients screened for TB from January to September 2016 in Luanda, the capital city of Angola. Approximately 66.5% of the patients were newly diagnosed with active TB. The residence area showed a significant relationship with TB (P = 0.025), whereas age group (P = 0.272), gender (P = 0.853), and HIV status (P = 0.284) did not showed any relationship with TB. Overall, 72.4% of TB patients had resistance to at least one of the anti-TB drugs. The risk of anti-TB drug resistance was higher in males (odds ratio [OR]: 1.22; 95% confidence interval [CI]: 0.42-3.58, P = 0.685] and in TB-HIV coinfected patients [OR: 1.39; (95% CI: 0.26-7.28), P = 0.700], whereas it was lower in patients aged 30 years or older (OR: 0.56; 95% CI: 0.18-1.69) P = 0.303) and in patients living in urbanized areas (OR: 0.74; 95% CI: 0.17-3.25; P = 0.685). Our findings showed that drug-resistant TB is emerging in Angola. Further studies on factors related to anti-TB drug resistance are urgently needed to ascertain the magnitude of the problem and to proffer strategies toward TB control in Angola.

Machine learning analysis of SERS fingerprinting for the rapid determination of Mycobacterium tuberculosis infection and drug resistance

•

Handheld Raman spectrometer is able to generate SERS spectra with sufficient quality for Mycobacterium tuberculosis detection.

•

It is feasible to accurately discriminate Mtb-positive sputum from Mtb-negative sputum through SERS spectrometry.

•

Pulmonary and extra-pulmonary Mtb strains were able to be accurately distinguished via SERS spectral analysis.

•

Profiling of antibiotic resistance of Mtb strains was successfully achieved through machine learning analysis of SERS spectra.

Over the past decades, conventional methods and molecular assays have been developed for the detection of tuberculosis (TB). However, these techniques suffer limitations in the identification of Mycobacterium tuberculosis (Mtb), such as long turnaround time and low detection sensitivity, etc., not even mentioning the difficulty in discriminating antibiotics-resistant Mtb strains that cause great challenges in TB treatment and prevention. Thus, techniques with easy implementation for rapid diagnosis of Mtb infection are in high demand for routine TB diagnosis. Due to the label-free, low-cost and non-invasive features, surface enhanced Raman spectroscopy (SERS) has been extensively investigated for its potential in bacterial pathogen identification. However, at current stage, few studies have recruited handheld Raman spectrometer to discriminate sputum samples with or without Mtb, separate pulmonary Mtb strains from extra-pulmonary Mtb strains, or profile Mtb strains with different antibiotic resistance characteristics. In this study, we recruited a set of supervised machine learning algorithms to dissect different SERS spectra generated via a handheld Raman spectrometer with a focus on deep learning algorithms, through which sputum samples with or without Mtb strains were successfully differentiated (5-fold cross-validation accuracy = 94.32%). Meanwhile, Mtb strains isolated from pulmonary and extra-pulmonary samples were effectively separated (5-fold cross-validation accuracy = 99.86%). Moreover, Mtb strains with different drug-resistant profiles were also competently distinguished (5-fold cross-validation accuracy = 99.59%). Taken together, we concluded that, with the assistance of deep learning algorithms, handheld Raman spectrometer has a high application potential for rapid point-of-care diagnosis of Mtb infections in future.