The study, published in BMC Infectious Diseases, drew on patients clinically diagnosed with cervical tuberculous lymphadenitis who were sampled at a single center between January 15, 2020, and February 24, 2025. Cervical tuberculous lymphadenitis is an infection of the neck’s lymph nodes by Mycobacterium tuberculosis, and Xpert positivity in this condition may depend on lesion characteristics and the composition of the specimen collected.

Among the positive results, 217 samples indicated rifampin-susceptible tuberculosis, 12 showed rifampin resistance, and 2 were rifampin-indeterminate. The test therefore provided information about rifampin susceptibility from the same sample used to confirm the diagnosis.

To find out which characteristics predicted a positive result, the team analyzed clinical variables, ultrasound findings, and specimen types using univariable and multivariable logistic regression. After adjusting for other factors, two determinants remained independently significant. Lymph nodes measuring at least 1.5 centimeters in diameter were associated with roughly double the odds of Xpert positivity, with an adjusted odds ratio of 2.20 and a 95 percent confidence interval of 1.26 to 3.94 (P = 0.006). Pus specimens carried far stronger weight, with an adjusted odds ratio of 6.38 and a 95 percent confidence interval of 3.39 to 12.83 (P < 0.001).

The raw positivity rates underscored the pattern. Xpert MTB/RIF detected tuberculosis in 81.5 percent of patients whose lymph nodes exceeded 1.5 centimeters. Pus specimens were even more striking, yielding positive results in 90.2 percent of cases.

The authors’ conclusion follows directly from these associations: during ultrasound-guided sampling, liquefactive necrotic areas should be preferentially targeted when they can be safely accessed. The study did not directly test whether such targeting improves detection rates, but the strong link between pus specimens and positive results supports that approach in this cohort.

The findings are grounded in the design of the study itself. As a single-center retrospective analysis, it reflects the patient population, equipment, and sampling practices of one institution, and patients were classified against clinical diagnoses rather than a single microbiological reference standard. The associations describe which sample characteristics accompanied positive tests in this cohort; they do not establish that targeting necrotic areas will raise detection rates in every setting.

Even so, the results give clinicians concrete guidance drawn from real-world practice: when tuberculosis of the neck lymph nodes is suspected and sampling is performed under ultrasound guidance, pus specimens and larger nodes were the characteristics most strongly linked to a positive Xpert MTB/RIF result. With 12 rifampin-resistant detections among the 231 positive cases, the study also illustrates how a single specimen can simultaneously confirm the diagnosis and provide rifampin susceptibility information.

Subject of Research: Clinical and sonographic determinants of Xpert MTB/RIF positivity in cervical tuberculous lymphadenitis

Article Title: Clinical and sonographic determinants of Xpert MTB/RIF positivity in cervical tuberculous lymphadenitis: a retrospective study

Article References: Zhang, W., Chen, P., Tang, W., Zhang, Y., Yu, X., & Wang, C. (2026). Clinical and sonographic determinants of Xpert MTB/RIF positivity in cervical tuberculous lymphadenitis: a retrospective study. BMC Infectious Diseases. https://doi.org/10.1186/s12879-026-14705-5

Image Credits: AI Generated

DOI: 10.1186/s12879-026-14705-5

Keywords: tuberculosis, Xpert MTB/RIF, cervical lymphadenitis, ultrasound-guided biopsy, rifampin resistance, liquefactive necrosis, pus specimen, retrospective study, Mycobacterium tuberculosis, diagnostic testing, Clinical, sonographic

Neither outcome had a significant annual difference or linear trend across the study period. The study, published in BMC Infectious Diseases , examined laboratory records generated from January 2020 through December 2024. The investigators used descriptive statistics and logistic regression to assess MTB detection, rifampicin resistance and associated factors.

Chi-square tests evaluated annual proportions, while continuous-year logistic regression assessed whether calendar year was associated with either outcome. A case-mix-adjusted sensitivity analysis examined temporal changes in MTB detection after accounting for age, sex, previous TB treatment, specimen type and referring facility. Firth-penalized logistic regression was used to assess the robustness of associations with rifampicin resistance in the presence of sparse resistant cases.

The records represented a hospital testing population rather than a population-based sample, so the results describe facility-level testing patterns and cannot directly establish trends in community TB incidence or drug resistance. Calendar year was not significantly associated with MTB detection in the continuous-year model. The estimated odds ratio was 1.007 per year, with a 95% confidence interval of 0.946 to 1.071.

Year was likewise not significantly associated with rifampicin resistance, for which the odds ratio was 1.089 and the 95% confidence interval was 0.848 to 1.399. Adjustment for the measured case-mix factors did not change the finding for MTB detection: the adjusted odds ratio per year was 1.025, with a 95% confidence interval of 0.957 to 1.097 and a p value of 0.481. The lack of a statistically detectable trend does not demonstrate that the underlying burden or resistance level remained constant.

Previous TB treatment had strong associations with both outcomes in the adjusted analyses. Compared with people without a reported history of prior TB treatment, those previously treated had an adjusted odds ratio of 13.99 for MTB detection, with a 95% confidence interval of 7.85 to 24.95. For rifampicin resistance, the corresponding adjusted odds ratio was 49.72, with a 95% confidence interval of 18.60 to 132.90.

These retrospective estimates represent associations among the tested records rather than causal effects or direct measures of individual risk. Male sex was also associated with rifampicin resistance, with an adjusted odds ratio of 4.59 and a 95% confidence interval of 1.32 to 16.00. HIV positivity was associated with MTB detection in univariable analysis, yielding a crude odds ratio of 7.03 and a 95% confidence interval of 1.99 to 24.77, but extensive missing HIV data constrained the interpretation of that result.

Only 28 rifampicin-resistance events were identified, contributing to wide confidence intervals, particularly for the association between previous TB treatment and resistance. The findings are also limited to one hospital, its recorded testing population and the five-year period from 2020 through 2024. A null temporal association in these records does not establish the absence of trends in other settings or at other times.

Overall, the analysis identified MTB in approximately one in nine tested records and rifampicin resistance in 5.6% of MTB-detected records with determinate results. Previous TB treatment was the factor most strongly associated with both outcomes, while the study detected no significant year-to-year shift in either MTB detection or Xpert-detected rifampicin resistance during the study period.

Subject of Research: Temporal patterns in tuberculosis detection and rifampicin resistance among Xpert-tested records at a northeastern Ethiopian hospital

Article Title: Trends in Mycobacterium tuberculosis detection and rifampicin resistance using Xpert MTB/RIF assay at Woldia comprehensive specialized hospital, Northeastern Ethiopia: a 5-year retrospective study

Article References: Tamrat, E., Kassanew, B., Mollaw, N. G., Girma, T., Asfaw, T., Habtamu, T., Jemal, A., Gashaw, M., Bazezew, A., Damtie, A. A., Gedfie, S., Gashaw, Y., Asmare, Z., Biset, S., & Reta, M. A. (2026). Trends in Mycobacterium tuberculosis detection and rifampicin resistance using Xpert MTB/RIF assay at Woldia comprehensive specialized hospital, Northeastern Ethiopia: a 5-year retrospective study. BMC Infectious Diseases. https://doi.org/10.1186/s12879-026-14670-z

Image Credits: AI Generated

DOI: 10.1186/s12879-026-14670-z

Keywords: tuberculosis, rifampicin resistance, Xpert MTB/RIF, Ethiopia, retrospective study, hospital records, Mycobacterium tuberculosis, diagnostic testing, Trends, Mycobacterium, detection, rifampicin

The two sequencing approaches represent different philosophies for reading genetic material from a patient sample. Targeted next-generation sequencing, often abbreviated tNGS, uses panels of primers or probes to enrich and amplify DNA from a predefined list of pathogens, which concentrates sequencing capacity on organisms that clinicians already suspect. Metagenomic next-generation sequencing, or mNGS, takes the opposite approach: it sequences all nucleic acid in a sample without any preselection, allowing the laboratory to detect virtually any microbe present, including unexpected or fastidious organisms that no one thought to test for. That breadth comes at a cost, both financially and computationally, because vast amounts of background human and environmental DNA must be filtered out before a pathogen signal emerges. The question facing hospitals is whether mNGS’s unbounded scope translates into measurably better care for patients with suspected pulmonary tuberculosis.

To answer that question fairly, the researchers confronted a familiar obstacle in observational medicine: patients are not assigned to tests at random. In routine practice, physicians choose mNGS or tNGS based on how sick a patient appears, what previous tests have shown, and what the patient can afford, which means simple comparisons between the two groups can be badly skewed. The team therefore turned to propensity score matching, a statistical technique that pairs patients from each group who share similar baseline characteristics, effectively simulating the balance of a randomized trial. After this matching procedure, the analysis rested on 403 patients with confirmed pulmonary infections, of whom 304 had undergone tNGS and 99 had received mNGS.

The headline diagnostic finding was one of statistical equivalence. In the matched cohorts, the final rate of tuberculosis diagnosis was 17.4 percent in the tNGS group versus 23.2 percent in the mNGS group, a difference that did not reach statistical significance, with a p value of 0.257. Similarly, the proportion of samples in which the Mycobacterium tuberculosis complex was directly detected by sequencing was 20.4 percent for tNGS and 28.3 percent for mNGS, again without a significant difference at p equals 0.134. When the researchers plotted receiver operating characteristic curves to summarize overall diagnostic accuracy, the area under the curve came to 0.936 for tNGS, with a 95 percent confidence interval of 0.898 to 0.975, and 0.967 for mNGS, with a confidence interval of 0.939 to 0.995. The comparison between these two areas yielded a p value of 1.000, about as close to a tie as statistics allows.

Beneath that tie, however, lay one of the study’s most striking results. Within the matched mNGS cohort of 99 patients, metagenomic sequencing achieved 100 percent sensitivity and a 100 percent negative predictive value for tuberculosis, meaning that in this dataset a negative mNGS result reliably ruled the disease out. That figure deserves careful interpretation: in the larger unmatched full cohort of 104 patients who received mNGS, sensitivity slipped to 95.8 percent and the negative predictive value to 98.7 percent, a reminder that perfect performance in a small matched subset can be fragile. Even so, the authors argue that such a high negative predictive value, if confirmed in larger studies, could make mNGS a powerful tool for excluding tuberculosis in diagnostically challenging cases, where every additional day of uncertainty carries clinical and emotional weight.

The sequencing tests were also benchmarked against the established tuberculosis diagnostic arsenal. In subset-specific area-under-the-curve analyses performed after propensity score matching, sequencing targeting the Mycobacterium tuberculosis complex, referred to as MTBC-NGS, outperformed the interferon-gamma release assay, the tuberculosis DNA test, and acid-fast staining, three workhorses of mycobacterial diagnosis that respectively measure immune response, detect bacterial DNA by conventional amplification, and visualize acid-fast bacilli under the microscope. Notably, MTBC-NGS also showed an advantage over the Xpert MTB/RIF assay, the World Health Organization-endorsed rapid molecular test that has transformed tuberculosis detection worldwide, although that advantage was smaller and only became statistically significant after the researchers applied a Bonferroni correction to account for multiple comparisons. The pattern suggests that while newer sequencing platforms do not render existing tools obsolete, they can extract additional diagnostic signal in the right clinical subsets.

Diagnostic performance, however, is only half the story, because healthcare systems must also weigh what each test costs and how it shapes the patient’s journey through the hospital. Here the study delivered a clear verdict: the mNGS group incurred substantially higher healthcare costs than the tNGS group. Metagenomic sequencing’s untargeted design requires deeper sequencing, more intensive bioinformatics, and greater laboratory infrastructure, expenses that are inevitably passed on to patients and payers. Targeted sequencing, by focusing resources on a curated panel of pathogens, achieves comparable diagnostic accuracy for tuberculosis at a lower price point, a distinction that matters enormously in the high-burden settings where tuberculosis testing decisions are made most often.

One widely held assumption did not survive the study’s statistical scrutiny. Earlier comparisons had suggested that patients who received mNGS experienced longer hospital stays, an observation that seemed intuitive given the turnaround time and complexity of untargeted sequencing. But when the researchers adjusted their analysis for the calendar period in which patients were tested, that difference in length of stay lost its statistical significance. The authors conclude that the apparent prolongation of hospitalization may have been attributable in part to temporal changes in clinical practice over the course of the study rather than to the test modality itself. It is a subtle but important methodological lesson: in fast-evolving fields like clinical genomics, when a test was ordered can matter as much as which test was ordered.

The study, led by Xinle Liang and colleagues in the Department of Respiratory and Critical Care Medicine at Yan’an University Affiliated Hospital, was approved by the hospital’s ethics committee and conducted in accordance with the Declaration of Helsinki. The team acknowledged the Xi’an Regional Medical Laboratory Center, which provided both tNGS and mNGS testing services, and the hospital’s clinical laboratory for supporting the work. As a retrospective, single-center analysis, the investigation carries inherent limitations that the authors themselves flag, most notably the modest size of the mNGS group even after matching, and the possibility that unmeasured differences between patients influenced both test selection and outcomes. The 100 percent sensitivity and negative predictive value observed in the matched mNGS cohort, in particular, is explicitly presented as a finding that requires validation in larger studies before it can guide practice.

For clinicians wrestling with suspected pulmonary tuberculosis, the practical message is one of complementarity rather than replacement. Metagenomic sequencing offers unmatched breadth and, in this cohort, an exceptional ability to rule tuberculosis out when results are negative, making it attractive for critically ill or diagnostically perplexing patients in whom the causative pathogen could be almost anything. Targeted sequencing delivers essentially equivalent accuracy for tuberculosis at lower cost, positioning it as the rational first-line genomic option when the clinical question is narrower. As sequencing costs continue to fall and bioinformatics pipelines mature, studies like this one, grounded in real-world propensity-matched cohorts rather than idealized trial conditions, will be essential for deciding which patients truly benefit from the most expensive diagnostic technology and which can be served just as well by its leaner cousin.

Subject of Research: Comparative diagnostic performance of targeted and metagenomic next-generation sequencing for pulmonary tuberculosis

Article Title: Clinical value of targeted next-generation sequencing and metagenomic next-generation sequencing in the diagnosis of pulmonary tuberculosis: a real-world propensity score matching study

Article References: Liang, X., Sun, Y., Sun, J., Zhao, J., He, F., & Bai, Z. (2026). Clinical value of targeted next-generation sequencing and metagenomic next-generation sequencing in the diagnosis of pulmonary tuberculosis: a real-world propensity score matching study. BMC Infectious Diseases. https://doi.org/10.1186/s12879-026-14537-3

Image Credits: AI Generated

DOI: 10.1186/s12879-026-14537-3

Keywords: pulmonary tuberculosis, targeted next-generation sequencing, metagenomic next-generation sequencing, propensity score matching, Mycobacterium tuberculosis complex, Xpert MTB/RIF, diagnostic accuracy, negative predictive value, healthcare costs, BMC Infectious Diseases, molecular diagnostics, retrospective study

The study, conducted by Bao Linh Nguyen and Thanh Binh Ngo of the University of Medicine and Pharmacy at Ho Chi Minh City, enrolled adults with HIV and microbiologically confirmed pulmonary tuberculosis at a tertiary referral hospital for tuberculosis and lung diseases between December 2022 and September 2023. Rather than averaging findings across the cohort, the researchers deliberately stratified patients by CD4 count, the standard laboratory measure of immune destruction, and tracked how three separate axes of the disease shifted across those strata: the radiographic appearance of the lungs on chest X-ray, the microbiological yield of sputum tests, and the presence of additional pulmonary pathogens sharing the same airways.

The patients themselves tell much of the story. The median CD4 count in the cohort was a startling 40.5 cells per microliter of blood, a level at which the immune system is barely functional; healthy counts sit above 500. Most patients were not yet taking antiretroviral therapy, and many were learning of their HIV diagnosis for the first time when they arrived at the hospital. This is the face of late presentation, and it is common in settings where HIV stigma, fragmented testing services and limited access to care delay diagnosis until opportunistic infections force patients through the door. Vietnam’s HIV epidemic, concentrated in certain regions and populations, continues to feed such late presentations into its tuberculosis wards.

The radiographic findings were the study’s most striking result. Among patients in the highest CD4 stratum, every single patient showed cavitation on chest radiography, and nearly nine in ten showed consolidation, the dense opacities that mark the body’s attempt to wall off infection with an intact inflammatory response. Large nodules appeared in two-thirds of this group. In the lowest CD4 stratum, the picture inverted almost completely: cavitation was seen in just 3.8 percent of patients, consolidation in 30.8 percent, and large nodules in 9.6 percent. Instead, half of the most immunosuppressed patients displayed ground-glass opacity, a hazy, frosted-glass pattern that in this population strongly evokes Pneumocystis jirovecii pneumonia or other non-tuberculous pathology. All four of these radiographic trends remained statistically significant after correction for multiple comparisons, with adjusted q-values of 0.025 or lower.

The biological explanation is straightforward but consequential. Cavitation in tuberculosis is not the work of the bacterium alone; it is the work of the immune response to it. Caseous necrosis, the destruction of lung tissue into a cheese-like core that can liquefy and drain into airways, depends on a vigorous CD4 T-cell driven inflammatory reaction. When CD4 cells are scarce, the lung cannot mount that reaction, so the bacilli multiply diffusely without forming cavities, and the radiograph shows vague haziness rather than the textbook cavity. The practical implication is that clinicians who dismiss tuberculosis because the X-ray lacks classic features may be precisely wrong in the patients at greatest risk, since atypical, ground-glass-predominant disease is a marker of the deepest immunosuppression.

That overlap with Pneumocystis is where the study becomes clinically urgent. Ground-glass opacity showed an unadjusted association with Pneumocystis positivity, with an odds ratio of 5.67, meaning patients with this pattern were more than five times as likely to harbor the fungus. Yet the diagnostic workup for Pneumocystis was strikingly incomplete: among patients with CD4 counts at or above 200 cells per microliter, only four of nine were ever tested, and none of those tested was positive. Overall, at least one additional pulmonary organism was documented in 28 of 92 patients, or 30.4 percent of the cohort. In other words, nearly a third of these patients were fighting more than one lung infection simultaneously, a reality that complicates every treatment decision, from empiric antibiotic choices to the timing and composition of antiretroviral initiation, where immune reconstitution inflammatory syndrome looms as a hazard.

On the microbiological axis, the study delivered a clear verdict on diagnostics. Sputum smear microscopy, the century-old workhorse of tuberculosis diagnosis in high-burden countries, detected acid-fast bacilli in only 63.3 percent of patients. The molecular Xpert MTB/RIF assay, which amplifies Mycobacterium tuberculosis DNA and simultaneously screens for rifampicin resistance, was positive in 91.1 percent. The paired comparison, analyzed with exact McNemar testing, produced a p-value below 0.0001, leaving little doubt that the molecular assay outperforms smear across every level of immunosuppression. Notably, neither test showed a significant ordered trend across CD4 strata, suggesting that the well-known paucibacillary appearance of tuberculosis in advanced HIV does not translate into a simple, predictable gradient of test positivity in real-world sputum samples.

Perhaps the most pragmatic finding concerns a test that almost any district laboratory can perform. The researchers explored whether the absolute lymphocyte count, a routine component of a complete blood count, could serve as a proxy for CD4 depletion. In exploratory receiver-operating-characteristic analysis, the absolute lymphocyte count discriminated patients with CD4 counts below 200 cells per microliter with an area under the curve of 0.89, with a 95 percent confidence interval of 0.79 to 0.96. An AUC near 0.9 represents strong discriminatory power, approaching the threshold often considered excellent. The authors are careful to frame this correctly: the lymphocyte count may provide a supportive indicator of advanced immunosuppression where CD4 testing infrastructure is unavailable, but it must not substitute for direct CD4 measurement, which remains the gold standard for staging HIV disease and guiding prophylaxis against opportunistic infections.

The study’s limitations deserve honest weight, and the authors acknowledge them directly. This was a single-center, cross-sectional investigation at a specialized referral hospital, which means the patients may not represent the broader population of people with HIV and tuberculosis in Vietnam or elsewhere. The design captures a snapshot rather than a trajectory, so it can describe associations but cannot establish how individual patients’ disease evolves as immune function changes. The Pneumocystis findings rest on microscopy, an insensitive method, and the testing gaps among higher-CD4 patients make the true prevalence of coinfection uncertain. The lymphocyte count analysis was explicitly exploratory. The authors describe their conclusions as hypothesis-generating and call for prospective confirmation, a framing that reflects appropriate scientific caution rather than weakness.

Even with those caveats, the findings land at a consequential moment. Tuberculosis remains the leading cause of death among people with HIV worldwide, and the World Health Organization’s targets for ending the dual epidemic depend on finding cases earlier and treating them correctly the first time. This study from Ho Chi Minh City distills that challenge into concrete clinical rules of thumb: in a patient with advanced HIV, a hazy chest X-ray without cavitation should raise, not lower, suspicion of tuberculosis; molecular testing should replace smear wherever possible; a substantial fraction of patients harbor secondary pulmonary pathogens that demand broader diagnostic thinking; and where CD4 counters are scarce, a simple lymphocyte count can flag the patients most likely to be dangerously immunosuppressed. For the clinicians working on the front lines of the HIV-tuberculosis collision, these are not abstractions. They are the difference between a diagnosis made in time and one made too late.

Subject of Research: Clinical, radiographic and microbiological presentation of HIV-associated pulmonary tuberculosis across CD4 count strata

Article Title: Clinical, radiographic and microbiological manifestations of newly diagnosed pulmonary tuberculosis across CD4 strata in adults with advanced HIV disease: a real-world cross-sectional study in southern Vietnam

Article References: Nguyen, B. L., & Ngo, T. B. (2026). Clinical, radiographic and microbiological manifestations of newly diagnosed pulmonary tuberculosis across CD4 strata in adults with advanced HIV disease: a real-world cross-sectional study in southern Vietnam. BMC Infectious Diseases. https://doi.org/10.1186/s12879-026-14507-9

Image Credits: AI Generated

DOI: 10.1186/s12879-026-14507-9

Keywords: pulmonary tuberculosis, HIV, advanced HIV disease, CD4 count, chest radiography, ground-glass opacity, Xpert MTB/RIF, sputum smear microscopy, Pneumocystis jirovecii, coinfection, absolute lymphocyte count, Vietnam