tuberculosis vaccine

Diagnosing asymptomatic tuberculosis: current approaches, emerging tools, and persistent challenges.

Wang Mao-Shui MS, Wei Dong-Yan DY, Liu Xu-Hui XH, Zhang Zhong-Fa ZF

Asymptomatic tuberculosis is a major but incompletely defined manifestation of the tuberculosis disease spectrum and an important challenge for active case finding. It is best understood as a symptom-defined and method-dependent phenotype rather than a uniform biological stage. Individuals classified as asymptomatic may have minimal or extensive radiographic abnormalities, low or intermittent bacillary shedding, or clinically inapparent disease that remains stable, regresses, fluctuates, or progresses. Differences in terminology, symptom ascertainment, population risk and diagnostic intensity have therefore led to substantial variation in how asymptomatic or subclinical tuberculosis is recognized and interpreted across studies and programmes. This Review examines current and emerging approaches for diagnosing asymptomatic tuberculosis, with emphasis on the interaction between epidemiological risk, radiological detectability, microbiological confirmation and longitudinal follow-up. Symptom-based screening and passive case finding miss a substantial proportion of bacteriologically or radiographically evident tuberculosis. Conventional sputum-based testing is constrained by difficulty obtaining specimens, paucibacillary disease, intermittent shedding and imperfect sensitivity. Chest radiography and computer-aided detection can expand screening capacity and standardize triage, but they cannot independently establish disease activity or exclude tuberculosis. Computed tomography and positron emission tomography/computed tomography provide more sensitive characterization in selected settings, although their cost, accessibility and limited specificity preclude routine use. Non-sputum pathogen assays and host biomarkers are promising because they may reduce dependence on spontaneous sputum, but most remain insufficiently validated, and their incremental clinical or programmatic value over imaging-based triage and conventional confirmation remains uncertain. The diagnostic challenge of asymptomatic tuberculosis lies not simply in the absence of symptoms, but in the unstable boundary between infection, early disease, radiological abnormality, microbiological detectability and future risk. Clinical and public health practice should therefore move beyond single-test strategies toward staged, risk-stratified diagnostic pathways that integrate symptom ascertainment, exposure risk, imaging, confirmatory microbiology, enhanced specimen collection and longitudinal reassessment. Such pathways should be viewed as flexible clinical-programmatic frameworks for organizing diagnostic uncertainty, guiding multidisciplinary decisions and generating testable hypotheses, rather than as validated treatment algorithms.

Next-Generation Mycobacterium tuberculosis Diagnostics: A Systematic Review of Molecular, CRISPR, and Biosensor Technologies.

Gomase Virendra S VS, Nimje Hemlata M HM, Kale Suraj S, Midathada Anil A et al.

TB (tuberculosis) due to Mycobacterium tuberculosis continues to be a significant worldwide health issue. Timely and reliable diagnostic tests will improve treatment outcomes and reduce the spread of disease. Traditional TB diagnostics currently available, such as smear microscopy and culture, have significant limitations with regard to sensitivity and turnaround times, especially for smear-negative cases and for tuberculosis in extrapulmonary locations. The purpose of this review is to analyze the evolution of TB diagnostics from traditional microbiology to new molecular diagnostic methods (including CRISPR, biosensor technology, and microfluidic methods), including an assessment of their diagnostic testing performance, feasibility, and potential for the future. The systematic narrative review aimed to systematically assess literature published from 2020 to 2025 retrieved from PubMed, Scopus, Web of Science, IEEE Xplore, ScienceDirect, and Google Scholar. The review was carried out according to the PRISMA guidelines and included 89 studies after screening and assessing for eligibility. The data were analysed qualitatively (i.e., through thematic analysis) by comparing data from conventional, molecular, and next-generation diagnostic methods. Molecular tests (e.g., GeneXpert, Line Probe Assays, PCR, and Whole Genome Sequencing) provide greater sensitivity and specificity than traditional methods and allow for faster diagnosis. Additionally, newer CRISPR-based tests, biosensors, and microfluidic devices hold promise for rapid, portable, point-of-care diagnosis of tuberculosis. The findings indicate that molecular diagnostics improve rapid detection and drug-resistance profiling, while CRISPR and biosensor platforms offer potential for rapid point-of-care testing. However, affordability, infrastructure, clinical validation, and scalability remain important barriers. The use of molecular diagnostic testing, CRISPR technology, biosensors, artificial intelligence, and portable platforms will dramatically enhance existing TB surveillance systems and strategies for controlling the disease globally.

Genomic profiling and drug resistance patterns of Mycobacterium tuberculosis in Indonesia: whole-genome sequencing of isolates from the 2017-2018 national Tuberculosis Drug Resistance Survey.

Rukminiati Yuni Y, Pangaribuan Lamria L, Adam Kindi K, Muna Fauzul F et al.

Drug-resistant tuberculosis remains a major public health challenge in Indonesia. This study aimed to characterize the genetic diversity, lineage distribution, and genotypic resistance profiles of Mycobacterium tuberculosis isolates across the Indonesian archipelago using whole-genome sequencing. A cross-sectional study was conducted using 1,281 analyzed MTB isolates derived from the 2017-2018 National Tuberculosis Drug Resistance Survey (DRS TB). Samples were screened via Xpert MTB/RIF and phenotypic drug susceptibility testing using the MGIT 960 system. Genomic DNA was extracted using the CTAB protocol. Whole-genome sequencing (WGS) libraries were prepared using the Nextera XT DNA Library Preparation Kit (Illumina, San Diego, CA, USA). Sequencing was performed on an Illumina MiSeq platform using the MiSeq Reagent Kit v3 (600 cycles), generating paired-end reads of 2 × 300 bp. To identify drug resistance-associated mutations and determine strain lineage/sub-lineages, raw sequencing reads were initially processed with Trimmomatic. The filtered reads were subsequently aligned to the Mycobacterium tuberculosis H37Rv reference genome (ATCC 27294;NC_000962.3) using the MTBseq pipeline, which the BWA-MEM algorithm (v0.7.17) for sequence mapping. Variant calling was carried out with Samtools mpileup (v1.6). Four major MTB lineages were identified: Lineage 4 (43.1%) was dominant, followed by Lineage 2 (30.4%) and Lineage 1 (26.3%), while Lineage 3 was rare, with only 0.16% detected. At the sub-lineage level, L2.2.1 (18.5%), L1.2.1 (11.3%), and L4.1.2.1 (9.7%) were the most prevalent. Resistance to first-line drugs was the most frequent, primarily driven by mutations in the katG p.Ser315Thr (7.5%) and rpoB p.Ser450Leu (5%), conferring isoniazid and rifampicin resistance, respectively. Second-line resistance was highest for Fluoroquinolones (2.03%). Notably, four pre-XDR strains (0.31%) were identified and validated across Java-Bali and Sumatera, all harboring critical gyrA mutations and rpoB mutations (p.Asp435Tyr, p.Asn437Asp, p.Ser450Leu, and p.Ser450Trp). The study confirms a high prevalence of L2 and L4 in Indonesia. The identification of pre-XDR-TB isolates among the national survey samples highlights an urgent need for expanded molecular surveillance. While newer drugs like Bedaquiline remain effective, the presence of specific gyrA mutations underscores the necessity of integrating WGS into national TB control programs to proactively manage resistance and optimize treatment regimens.

Monitoring changes in the prevalence of the Beijing lineage of Mycobacterium tuberculosis in Ecuador: 2018 and 2023.

Rodríguez-Pazmiño Ángel Sebastián ÁS, Pozo-Estupiñán Lilian Paola LP, Cedeño-Vásquez Melany Patricia MP, Trejo Cedeño Irina I et al.