Transcriptomic and proteomic analyses of Mycobacterium tuberculosis strains isolated from tuberculous meningitis patients.

Background: Tuberculous meningitis (TBM) is caused by the dissemination of Mycobacterium tuberculosis (MTB) from the primary site of infection to the central nervous system. However, the bacterial factors associated with the pathogenesis of TBM remain unclear. This study employed transcriptomic and proteomic methods to comprehensively analyze the changes in genes and proteins and their associated pathways in MTB strains isolated from cerebrospinal fluid (CSF) of TBM and sputum of pulmonary TB (PTB) cases. Methodology: Five MTB strains were subjected to OMICs (transcriptomic and proteomic) analysis. Among five MTB strains, two were isolated from CSF and sputum samples of the same patient with PTB and TBM infections, one from the sputum of a different PTB patient, and a strain obtained from the CSF of another TBM patient. H37Rv was used as a reference strain. The reliability of transcriptomic results was validated by real time polymerase chain reaction with selected genes from 100 MTB isolates (CSF, 50 and sputum, 50). Results: The transcriptomic study revealed that overlapping differentially expressed genes of MTB strains isolated from TBM patients showed featured enrichment in benzoate degradation, lysine degradation, tryptophan metabolism, fatty acid degradation, ATP binding cassette transporters, microbial metabolism in diverse environments, biosynthesis of antibiotics, and metabolic pathways. Eleven genes were upregulated, and four were downregulated in MTB strains isolated from TBM compared to PTB. From proteomic analysis, we identified three candidate proteins belonging to plasminogen binding proteins (PBP) (enolase, dnaK, and isocitrate lyase 1) that were significantly upregulated in MTB strains isolated from TBM. Conclusion: Overall, the transcriptomic and proteomic analyses provided an important base for understanding the unique feature of TBM pathogenesis. To the best of our knowledge, this is the first report highlighting the importance of PBPs on TBM pathogenesis.

The new Xpert Mycobacterium tuberculosis/rifampicin (MTB/Rif) Ultra assay in comparison to Xpert MTB/Rif assay for diagnosis of tuberculosis in children and adolescents.

BACKGROUND: Microbiological diagnosis of pediatric tuberculosis (TB) using conventional microbiological techniques has been challenging due to paucibacillary nature of the disease. Molecular methods using cartridge-based tests like Xpert, have immensely improved diagnosis. A novel next-generation cartridge test, Xpert Ultra, incorporates two additional molecular targets and claims to have much lower detection limit. We attempted to compare the two techniques in presumptive pediatric TB patients. OBJECTIVES: The aim of this study was to compare the diagnostic performance of Xpert MTB/Rif Ultra with Xpert MTB/Rif for the detection of pediatric TB. STUDY DESIGN: This is an observational comparative analytical study. METHODS: Children under 15 years of age with presumptive TB were enrolled. Appropriate specimens were obtained (sputum, induced sputum or gastric aspirate for suspected pulmonary TB, cerebrospinal fluid for suspected tubercular meningitis and pleural fluid for suspected tubercular pleural effusion), subjected to smear microscopy, mycobacterial culture, Xpert and Xpert ultra tests and other appropriate diagnostic investigations. RESULTS: Out of 130 enrolled patients, 70 were diagnosed with TB using a composite reference standard (CRS). The overall sensitivity of Xpert was 64.29% [95% confidence interval (CI) 51.93-75.93%] and that of Xpert Ultra was 80% (95% CI 68.73-88.61%) with 100% overall specificity for both. The sensitivity of Xpert and Xpert Ultra in pulmonary specimens (n = 112) was 66.67% and 79.37% and in extrapulmonary specimens (n = 18) was 42.86% and 85.71%, respectively. CONCLUSION: Our study found Ultra to be more sensitive than Xpert for the detection of Mycobacterium tuberculosis in children. Our findings support the use of Xpert Ultra as initial rapid molecular diagnostic test in children under evaluation for TB.

Advancing Diagnosis and Treatment in People Living with HIV and Tuberculosis Meningitis.

PURPOSE OF REVIEW: Tuberculous meningitis (TBM) is the most severe form of tuberculosis. Inadequate diagnostic testing and treatment regimens adapted from pulmonary tuberculosis without consideration of the unique nature of TBM are among the potential drivers. This review focuses on the progress being made in relation to both diagnosis and treatment of TBM, emphasizing promising future directions. RECENT FINDINGS: The molecular assay GeneXpert MTB/Rif Ultra has improved sensitivity but has inadequate negative predictive value to "rule-out" TBM. Evaluations of tests focused on the host response and bacterial components are ongoing. Clinical trials are in progress to explore the roles of rifampin, fluoroquinolones, linezolid, and adjunctive aspirin. Though diagnosis has improved, novel modalities are being explored to improve the rapid diagnosis of TBM. Multiple ongoing clinical trials may change current therapies for TBM in the near future.

Single-cell analysis reveals changes in BCG vaccine-injected mice modeling tuberculous meningitis brain infection.

Tuberculous meningitis (TBM) is the most severe and deadly manifestation of tuberculosis. Neurological complications are observed in up to 50% of patients affected. Here, attenuated Mycobacterium bovis are injected into the cerebellum of mice, and histopathological images and cultured colonies confirm successful brain infection. Then, whole-brain tissue is dissected for 10X Genomics single-cell sequencing, and we acquire 15 cell types. Transcriptional changes of inflammation processes are found in multiple cell types. Specifically, Stat1 and IRF1 are shown to mediate inflammation in macrophages and microglia. For neurons, decreased oxidative phosphorylation activity in neurons is observed, which corresponds to TBM clinical symptoms of neurodegeneration. Finally, ependymal cells present prominent transcriptional changes, and decreased FERM domain containing 4A (Frmd4a) may contribute to TBM clinical symptoms of hydrocephalus and neurodegeneration. This study shows a single-cell transcriptome of M. bovis infection in mice and improves the understanding of brain infection and neurological complications in TBM.

Cerebrospinal fluid lactate as a predictive biomarker for tuberculous meningitis diagnosis.

OBJECTIVES: The definitive diagnosis of tuberculous meningitis (TBM) is achieved by identifying Mycobacterium tuberculosis (MTb) in cerebrospinal fluid (CSF); however, diagnostic confirmation is difficult due to the inability of current tests for an effective diagnosis. Our objective was to retrospectively assess the characteristics of CSF lactate (CSF-LA) as an adjunct biomarker in the diagnosis of TBM. METHODS: 608 CSF laboratory reports were assessed. Of these, 560 had clinically suspected TBM. These were classified as definite (n=36), probable (23), possible (278), or non-TBM (223) according to the international consensus TBM case definitions. An additional 48 CSF samples were negative controls with normal CSF. RESULTS: Against a reference standard of definite TBM, the cut-off value for CSF-LA was 4.0 mmol/L, the area under the ROC curve was 0.88 (95% CI, 0.82-0.94; p=0.0001), sensitivity was 69%, specificity 90%, negative predictive value 98%. These diagnostic parameters decreased when calculated against those of the other categories of TBM. CSF-LA exhibited high specificity, efficiency, negative predictive value, and clinical utility index in all the groups studied. CONCLUSIONS: CSF-LA is a useful diagnostic marker to rule out TBM when associated with conventional microbiology tests, nucleic acid amplification assays, and clinical algorithms, particularly in endemic areas.

Cerebrospinal fluid AFB smear in adults with tuberculous meningitis: A systematic review and diagnostic test accuracy meta-analysis.

BACKGROUND: Cerebrospinal fluid (CSF) Ziehl-Neelsen acid-fast bacilli (AFB) smear is a rapid, cheap, widely available test for tuberculous meningitis (TBM). Yet, reported test sensitivity is highly variable. We performed a systematic review and meta-analysis for CSF AFB smear vs. other mycobacterial tests to diagnose TBM. METHODS: We searched MEDLINE and Embase for studies reporting sensitivity and specificity of AFB smear against mycobacterial tests (reference standard) in adults (≥15 years) with suspected TBM. We used the QUADAS-2 tool to assess risk of bias. We estimated pooled sensitivity and specificity of AFB smear versus the reference standard using random-effects bivariate modeling. We used the I2 statistic to assess heterogeneity between studies. RESULTS: Of 981 articles identified, 11 were eligible for inclusion with a total of 1713 participants. Seven studies were from high-TB burden settings and 4 from low-TB burden settings. The pooled sensitivity and specificity of CSF AFB smear were 8% (95%CI 3-21) and 100% (95%CI 90-100), with substantial heterogeneity in diagnostic performance (I2 >95% for both) and reference standards. CONCLUSION: CSF AFB smear has poor sensitivity in most settings. If other more sensitive tests are available, those should be used preferentially rather than CSF AFB smear.

Utility of cell-free transrenal DNA for the diagnosis of Tuberculous Meningitis: A proof-of-concept study.

Tuberculous Meningitis (TBM) diagnosis remains a grave challenge. We evaluated the utility of extracellular vesicles (EVs) as a source of cell-free transrenal-mycobacterial DNA (cf-Tr-MTB DNA) for TBM diagnosis from urine samples. We developed a qPCR-assay targeting a highly repetitive 36-bp sequence specific to Mycobacterium tuberculosis complex. EVs were isolated from urine samples of suspected TBM groups (n = 44) [categorized using composite reference standard as 'Definite' TBM (n = 8), 'Probable' TBM (n = 15), 'Possible' TBM (n = 21)] and 'Non-TBM' group (n = 26). cf-Tr-MTB DNA-based qPCR assay was applied to DNA isolated from EVs (EV-DNA) and EV-free-fraction (EV-free DNA). ROC-curves were generated using qPCR results of 'Definite' TBM and 'Non-TBM' category in both EV-DNA and EV-free DNA samples and cut-off values were selected to provide 100% (95%CI:69.1-100) specificity. The cf-Tr-MTB DNA assay gave a sensitivity of 54.5% (95%CI:38.8-69.6) for EV-DNA and 77.3% (95%CI:62.1-88.5) for EV-free DNA in the TBM group (n = 44). The combination of EV-DNA and EV-free DNA results (corresponding to performance cf-Tr MTB DNA assay in urine), gave an overall sensitivity of 81.8% (95%CI:67.2-91.8) in the TBM group. Our results confirmed EVs as one of the sources of cf-Tr-MTB DNA and we believe the cf-Tr-MTB DNA-based qPCR assay has a potential application for TBM diagnosis.

NMR based CSF metabolomics in tuberculous meningitis: correlation with clinical and MRI findings.

We report the potential role of 1H Nuclear Magnetic Resonance (NMR) based metabolomics in tuberculous meningitis (TBM). We also correlate the significant metabolites with clinical-radiological parameters. Forty-three patients with TBM were included, and their severity of meningitis was graded as stages I to III, and patients with positive Mycobacterium tuberculosis or its nucleic acid was considered as definite TBM. 1H NMR-based metabolomic study was performed on (CSF) samples, and the significant metabolites compared to healthy controls were identified. Outcome at three months was defined as death, poor and good based on the modified Rankin Scale. These metabolites were compared between definite and probable groups of TBM, and also correlated with MRI findings. About 11 metabolites were found to be significant for distinguishing TBM from the controls. In TBM, lactate, glutamate, alanine, arginine, 2-hydroxyisobutyrate, formate, and cis-aconitate were upregulated, and glucose, fructose, glutamine, and myo-inositol were downregulated compared to the controls. For differentiating TBM from the controls, the AUC of the ROC curve generated using these significant metabolites was 0.99, with a 95% confidence interval from 0.96 to 1, demonstrating that these metabolites were able to classify cases with good sensitivity and specificity. Lactate concentration in CSF correlated with hemoglobin, CSF glucose, and infarction. The outcome did not correlate with metabolomics parameters. NMR-based CSF metabolomics have a potential role in differentiating TBM from the controls.

Targeted Therapy of Tuberculous Meningitis in Rats with Methylprednisolone Composite Nanoparticles.

It was to investigate the targeted therapeutic effect of methylprednisolone (MPS) composite nanoparticles (NPs) on tuberculous meningitis (TBM) in rats. A total of 180 special pathogen-free (SPF) Sprague Dawley (SD) rats (male) were randomly and equally assigned to the normal control group, TBM infection group, and TBM treatment group. Those in the TBM infection group and the TBM treatment group were injected with Mycobacterium tuberculosis suspension via the tail vein. After the TBM model was established, rats in the TBM treatment group were injected intraperitoneally with methylprednisolone-nano sterically stabilized liposomes (MPS-NSSLs), and those in the normal control group were injected with an equal amount of normal saline. MPS-NSSLs were prepared, and their quality evaluation, encapsulation rate, drug-lipid ratio, and stability were detected. The particle size distribution of MPS-NSSLs was 95.4 ± 0.7 nm, showing a complete spherical structure, and the encapsulation rate was 91.24 ± 0.27 %, and the drug-lipid ratio was about 0.4. After 7 days of treatment, the water content of brain tissue in the TBM infection group was drastically superior to that in the control group (P<0.05); Evans blue (EB) content in the TBM infection group was dramatically superior to that in the control group (P<0.05). The TBM rat model was successfully established, and this model verified that MPS-NSSLs had the characteristics of high efficiency and low toxicity in the treatment of TBM rats.

Development and validation of a new scoring system for the early diagnosis of tuberculous meningitis in adults.

We developed and validated a new diagnostic scoring system by simultaneously comparing 28 factors (including clinical, laboratory, and imaging) of HIV uninfected adult tuberculous meningitis (TBM) with viral meningitis (VM), bacterial meningitis (BM), and cryptococcal meningitis (CM). Predictors of TBM diagnosis obtained by logistic regression. A total of 382 patients with intracranial infection participated, and eight factors were independently associated with TBM diagnosis: symptom duration, evidence of extracranial tuberculosis, cerebrospinal fluid (CSF) leukocyte, CSF neutrophil, CSF protein, low serum sodium, meningeal enhancement, and tuberculomas. Factors are assigned according to weight, a score of ≥ 5 was suggestive of TBM with a sensitivity of 85.8% and a specificity of 87.7%, and the area under the receiver operating characteristic curve was 0.923. When applied to a prospective validation cohort, this scoring model showed robust performance. Our study suggests that the application of this score can help diagnose TBM more efficiently.

Diagnostic accuracy of GeneXpert MTB/RIF assay for detection of tubercular pleural effusion.

India has been engaged in tuberculosis (TB) control activities for over 50 years and yet TB continues to remain India's important public health problem. The present study was conducted to compare the performance of GeneXpert MTB/RIF (GXpert) assay with composite reference standard in diagnosing cases of tubercular pleural effusion (TPE) and to evaluate the reliability of rifampicin resistance. A cross-sectional study was performed in a Department of Medicine of a rural teaching tertiary care hospital in central India. In all consecutive patients with pleural effusion on chest radiograph presenting to Department of Medicine, GXpert assay and composite reference standard was performed to evaluate the diagnostic accuracy of GXpert assay for detecting TPE in comparison to composite reference standard. Standard formulae were used to calculate the sensitivity, specificity, positive predictive values (PPV), negative predictive values (NPV), positive likelihood ratios (LR+) and negative likelihood ratios (LR-). Mc-Nemar's test was applied to compare variables. All comparisons were two-tailed. We considered the difference to be statistically significant if the P value was less than 0.05. The sensitivity of the GXpert assay in diagnosing TPE was 16.6% among 158 study participants, the specificity was 100% and diagnostic accuracy was 52.5% which was statistically significant (p value < 0.05). It had a PPV of 100% (95%CI: 88.3% - 100%) and a NPV of 47.5% (95%CI: 39.3% - 55.7%). The LR+ and LR-were 23.5 (95%CI: 1.43-38.6) and 0.83 (95%CI: 0.76-0.91) respectively. GXpert assay has a very high specificity in diagnosing TPE but has a low sensitivity. In comparison to composite reference standard Thus its clinical utility is limited when used as a standalone test. A physician's clinical acumen in combination with routine pleural fluid analysis should be the key factor in the diagnosis of TPE in clinically and radiologically suspected patients, especially in high TB burden countries.

Phenotype of Peripheral NK Cells in Latent, Active, and Meningeal Tuberculosis.

The mechanisms underlying the immunopathology of tuberculous meningitis (TBM), the most severe clinical form of extrapulmonary tuberculosis (TB), are not understood. It is currently believed that the spread of Mycobacterium tuberculosis (Mtb) from the lung is an early event that occurs before the establishment of adaptive immunity. Hence, several innate immune mechanisms may participate in the containment of Mtb infection and prevent extrapulmonary disease manifestations. Natural killer (NK) cells participate in defensive processes that distinguish latent TB infection (LTBI) from active pulmonary TB (PTB). However, their role in TBM is unknown. Here, we performed a cross-sectional analysis of circulating NK cellCID="C008" value="s" phenotype in a prospective cohort of TBM patients (n = 10) using flow cytometry. Also, we addressed the responses of memory-like NK cell subpopulations to the contact with Mtb antigens in vitro. Finally, we determined plasma levels of soluble NKG2D receptor ligands in our cohort of TBM patients by enzyme-linked immunosorbent assay (ELISA). Our comparative groups consisted of individuals with LTBI (n = 11) and PTB (n = 27) patients. We found that NK cells from TBM patients showed lower absolute frequencies, higher CD69 expression, and poor expansion of the CD45RO+ memory-like subpopulation upon Mtb exposure in vitro compared to LTBI individuals. In addition, a reduction in the frequency of CD56brightCD16- NK cells characterized TBM patients but not LTBI or PTB subjects. Our study expands on earlier reports about the role of NK cells in TBM showing a reduced frequency of cytokine-producing cells compared to LTBI and PTB.

Serum and cerebrospinal fluid host proteins indicate stroke in children with tuberculous meningitis.

INTRODUCTION: Stroke is a common complication in children with tuberculous meningitis (TBM). Host proteins may give us insight into the mechanisms of stroke in TBM and serve as biomarkers for detection of stroke, however, they have not been widely explored. In this study, we compared the concentrations of cerebrospinal fluid (CSF) and serum proteins between children who had TBM-related stroke and children with TBM without stroke. METHODS: We collected CSF and serum from 47 children consecutively admitted to the Tygerberg Academic Hospital in Cape Town, South Africa between November 2016, and November 2017, on suspicion of having TBM. A multiplex platform was used to measure the concentrations of 69 host proteins in CSF and serum from all study participants. RESULTS: After classification of study participants, 23 (48.9%) out of the 47 study participants were diagnosed with TBM, of which 14 (60.9%) demonstrated radiological arterial ischemic infarction. The levels of lipocalin-2, sRAGE, IP-10/ CXCL10, sVCAM-1, MMP-1, and PDGF-AA in CSF samples and the levels of D-dimer, ADAMTS13, SAA, ferritin, MCP-1/ CCL2, GDF-15 and IL-13 in serum samples were statistically different between children who had TBM-related stroke and children with TBM without stroke. After correcting for multiple testing, only the levels of sVCAM-1, MMP-1, sRAGE, and IP-10/ CXCL10 in CSF were statistically different between the two groups. CSF and serum protein biosignatures indicated stroke in children diagnosed with TBM with up to 100% sensitivity and 88.9% specificity. CONCLUSION: Serum and CSF proteins may serve as biomarkers for identifying individuals with stroke amongst children diagnosed with TBM at admission and may guide us to understand the biology of stroke in TBM. This was a pilot study, and thus further investigations in larger studies are needed.

Therapeutic drug monitoring of intravenous anti-tuberculous therapy: management of an 8-month-old child with tuberculous meningitis.

Tuberculous meningitis (TBM) is now uncommon in high-income countries. It is the most severe form of extrapulmonary tuberculosis with high rates of mortality and morbidity if diagnosis and treatment are delayed. An 8-month-old girl with TBM who was treated with high-dose intravenous anti-tuberculous drugs (ATD) is reported. Therapeutic drug monitoring (TDM) of isoniazid and rifampicin was undertaken by measuring serial drug concentrations in serum and cerebrospinal fluid (CSF). There was rapid eradication of Mycobacterium tuberculosis from the CSF with a good clinical outcome and no adverse effects. Using high-dose regimens of intravenous ATD to treat TBM is an important option in order to obtain sufficient CSF diffusion. When available, TDM and a multidisciplinary approach are essential for efficient therapeutic management.

A Bayesian analysis of the association between Leukotriene A4 Hydrolase genotype and survival in tuberculous meningitis.

Tuberculous meningitis has high mortality, linked to excessive inflammation. However, adjunctive anti-inflammatory corticosteroids reduce mortality by only 30%, suggesting that inflammatory pathophysiology causes only a subset of deaths. In Vietnam, the survival benefit of anti-inflammatory corticosteroids was most pronounced in patients with a C/T promoter variant in the leukotriene A4 hydrolase (LTA4H) gene encoding an enzyme that regulates inflammatory eicosanoids. LTA4H TT patients with increased expression had increased survival, consistent with corticosteroids benefiting individuals with hyper-inflammatory responses. However, an Indonesia study did not find an LTA4H TT genotype survival benefit. Here using Bayesian methods to analyse both studies, we find that LTA4H TT genotype confers survival benefit that begins early and continues long-term in both populations. This benefit is nullified in the most severe cases with high early mortality. LTA4H genotyping together with disease severity assessment may target glucocorticoid therapy to patients most likely to benefit from it.

Tuberculous meningitis is a serious infection of the lining of the brain, which affects over 100,000 people a year. Without treatment, it is always fatal: even with proper antibiotics, about a quarter of patients do not survive and many will have permanent brain damage. Overactive inflammation is thought to contribute to this process. Corticosteroid drugs, which dampen the inflammatory process, are therefore often used during treatment. However, they merely reduce mortality by 30%, suggesting that only some people benefit from them. Two recent studies have linked the genetic makeup of individuals who have tuberculous meningitis to how they respond to corticosteroids. There were, in particular, differences in the LTA4H gene that codes for an inflammation-causing protein. According to these results, only individuals carrying high-inflammation versions of the LTA4H gene would benefit from the treatment. Yet a third study did not find any effect of the genetic background of patients. All three papers used frequentist statistics to draw their conclusions, only examining the percentage of people who survived in each group. Yet, this type of analysis can miss important details. It also does not work well when the number of patients is small, or when the effectiveness of a drug varies during the course of an illness. Another method, called Bayesian statistics, can perform better under these limitations. In particular, it takes into account the probability of an event based on prior knowledge ­ for instance, that the risk of dying varies smoothly with time. Here, Whitworth et al. used Bayesian statistics to reanalyse the data from these studies, demonstrating that death rates were correlated with the type of LTA4H gene carried by patients. In particular, corticosteroid treatment worked best for people with the high inflammation versions of the gene. However, regardless of genetic background, corticosteroids were not effective if patients were extremely sick before being treated. The work by Whitworth et al. demonstrates the importance of using Bayesian statistics to examine the effectiveness of medical treatments. It could help to design better protocols for tuberculous meningitis treatment, tailored to the genetic makeup of patients.

Evaluation of CSF pyrosequencing to diagnose tuberculous meningitis: A retrospective diagnostic accuracy study.

BACKGROUND: We evaluated the performance of pyrosequencing, a genotypic test which detects TB and XDR-defining mutations within 6 h, directly on CSF samples for diagnosing TB meningitis(TBM). METHODS: This retrospective, diagnostic accuracy study was conducted in Hinduja hospital, Mumbai from May-2017 to May-2019. 107 consecutive patients with physician-suspected TBM for whom CSF pyrosequencing was requested were screened. Seven patients with incomplete data were excluded. Diagnostic accuracy of pyrosequencing was compared with Xpert MTB/Rif and TBMGIT (TB Mycobacterial Growth Indicator Tube) culture against the uniform case definition of definite or probable TBM. Susceptibility concordance rate of pyrosequencing with TBMGIT culture and Xpert MTB/Rif was determined. RESULTS: The study cohort comprised of 100 patients[Definite(n = 33), Probable(n = 20), Possible(n = 30), Alternative(n = 17)] with 50% males[median age(years):38(Range:2-87)]. Against the uniform case definition, pyrosequencing had 98·11%(95%CI 89·93-99·95; n = 52/53) sensitivity and 97·79%(86·31-99·67; n = 44/45) negative predictive value(NPV) compared with 43.39%(29·83-57·72; n = 23/53,p < 0.0001) sensitivity and 61.04%(55·31-66·48; n = 47/77) NPV for Xpert MTB/Rif and 45·28%(31·56-59·55; n = 24/53,p < 0.0001) sensitivity and 61·84%(55·92-67·43; n = 47/76) NPV for TBMGIT culture. Susceptibility concordance rate of pyrosequencing with phenotypic Drug Susceptibility Testing was 91.3%(n = 21/23) and with Xpert MTB/Rif was 95·45%(n = 21/22). CONCLUSION: CSF pyrosequencing is significantly more sensitive than Xpert MTB/Rif and TBMGIT culture for diagnosing TBM. Additionally, it facilitates early therapeutic decision-making by providing information on XDR-defining mutations.

Diagnostic accuracy of Xpert MTB/RIF Ultra for tuberculous meningitis in a clinical practice setting of China.

A comparative performance evaluation of the novel Xpert MTB/RIF Ultra (Xpert Ultra) and MTB/RIF Xpert (Xpert) for tuberculous meningitis (TBM) diagnosis was performed. The cerebrospinal fluids of suspected TBM patients were collected consecutively and subjected to smear microscopy, culture, Xpert, and Xpert Ultra. In total, 160 patients were recruited. Xpert Ultra produced a higher sensitivity (45%, 34 of 76) than Xpert (28%, 21 of 76; P = 0.001) and culture (18%, 14 of 76; P < 0.001), respectively. Inclusion of Xpert Ultra outcomes increased the percentage of definite TBM case from 36% (27 of 76) to 51% (39 of 76). Both Xpert Ultra and Xpert accurately identified the one rifampicin (RIF)-resistant and the 5 RIF-sensitive cases defined by phenotypic drug sensitivity test. The specificities of all of the culture, Xpert and Xpert Ultra were 100% (45 of 45). Xpert Ultra outperformed both Xpert and culture for TBM diagnosis, which may speed up the appropriate treatment of patients in clinical practice.

Comparison of the efficacy of metagenomic next-generation sequencing and Xpert MTB/RIF in the diagnosis of tuberculous meningitis.

Metagenomic next-generation sequencing (mNGS) is an emerging sequence-based method that detects genomic information of pathogenic microorganisms from a wide range of clinical specimens. The mNGS has moderate sensitivity and very high specificity for tuberculous meningitis, and the validity of mNGS was higher than that of Xpert MTB/RIF.

Diagnostic accuracy of Xpert MTB/RIF for tuberculous meningitis: systematic review and meta-analysis.

OBJECTIVE: This systematic review evaluated the diagnostic accuracy of Xpert MTB/RIF to detect tuberculous meningitis (TBM). METHODS: PubMed and five other databases were systematically searched through March 2019. All studies evaluating diagnostic accuracy of Xpert MTB/RIF on cerebrospinal fluid (CSF) samples were included. Reference standards were definitive or definite plus probable TBM. The quality of studies was assessed by the QUADAS-2 tool. We performed bivariate random-effects meta-analysis and calculated summary diagnostic statistics. RESULTS: We identified 30 studies (n = 3972 participants), including 5 cohort studies and 25 cross-sectional studies. Reference standards were definite TB (n = 28 studies) or definite plus probable TBM (n = 6 studies). The pooled Xpert MTB/RIF sensitivity was 85% (95% CI, 70-93%), and specificity was 98% (95% CI, 97-99%) with a negative likelihood ratio of 0.15 (95% CI, 0.04-0.27) for definite TBM. For probable TBM cases, pooled sensitivity was 81% (95% CI, 66-90%), and specificity was 99% (95% CI, 97-99%). For both reference standard types, meta-analyses showed a C-statistic area under the curve of 0.98. The QUADAS-2 tool revealed low risk of bias as well as low concerns regarding applicability. Methodological heterogeneity was high among studies. CONCLUSIONS: Xpert MTB/RIF showed high accuracy for TBM diagnosis, but a negative Xpert MTB/RIF test does not rule out TBM. Repeat Xpert testing may be necessary. In clinical practice, Xpert MTB/RIF adds speed and sensitivity when compared to classic TBM diagnostic methods or previous commercial nucleic acid amplification techniques. More studies and better strategies for rapidly confirming a diagnosis of TBM in children are urgently needed.

OBJECTIF: Cette revue systématique a évalué la précision diagnostique de Xpert MTB/RIF pour détecter la méningite tuberculeuse (MTB). MÉTHODES: PubMed et cinq autres bases de données ont fait l'objet d'une recherche systématique jusqu'en mars 2019. Toutes les études évaluant la précision du diagnostic de Xpert MTB/RIF sur des échantillons de liquide céphalo-rachidien (LCR) ont été incluses. Les étalons de référence étaient des MTB définitives ou définitives et probables. La qualité des études a été évaluée par l'outil QUADAS-2. Nous avons effectué une méta-analyse des effets aléatoires bivariés et calculé des statistiques de résumés diagnostiques. RÉSULTATS: Nous avons identifié 30 études (n = 3.972 participants), dont 5 études de cohorte et 25 études transversales. Les étalons de référence étaient la TB définitive (n = 28 études) ou la MTB définitive et probable (n = 6 études). La sensibilité poolée Xpert MTB/RIF était de 85% (IC95%: 70-93%) et la spécificité était de 98% (IC95%: 97-99%) avec un rapport de vraisemblance négatif de 0,15 (IC95%: 0,04-0,27) pour la MTB définitive. Pour les cas probables de la MTB, la sensibilité poolée était de 81% (IC95%: 66-90%) et la spécificité était de 99% (IC95%: 97-99%). Pour les deux types d'étalons de référence, les méta-analyses ont montré une aire statistique C sous la courbe de 0,98. L'outil QUADAS-2 a révélé un faible risque de biais ainsi que de faibles préoccupations concernant l'applicabilité. L'hétérogénéité méthodologique était élevée parmi les études. CONCLUSIONS: Xpert MTB/RIF a montré une grande précision pour le diagnostic de la MTB, mais un test Xpert MTB/RIF négatif n'exclut pas la MTB. La répétition du tests Xpert peut être nécessaire. Dans la pratique clinique, Xpert MTB/RIF ajoute vitesse et sensibilité par rapport aux méthodes de diagnostic classiques de la MTB ou aux précédentes techniques d'amplification d'acide nucléique commerciales. Des études supplémentaires et de meilleures stratégies pour confirmer rapidement un diagnostic de MTB chez les enfants sont nécessaires d'urgence.

Cerebrospinal fluid IL-1ß is elevated in tuberculous meningitis patients but not associated with mortality.

Inflammation contributes to the pathophysiology and high mortality of tuberculous meningitis. The IL-1ß pathway has been implicated in immunopathology and could be a target for host-directed therapy. IL-1ß was elevated in the cerebrospinal fluid (CSF) of 225 HIV-uninfected tuberculous meningitis patients in Indonesia compared to controls, but did not predict subsequent mortality, nor did IL-6 or IL-1Ra. Furthermore, genetic loci known to regulate IL1B gene expression did not predict mortality in 443 tuberculous meningitis patients, although two of these loci did predict CSF IL-1ß concentrations. Collectively, these data argue against a role for IL-1ß targeted host-directed therapy in tuberculous meningitis.