Tuberculous meningitis: more questions, still too few answers

18FDG-Positron Emission Tomography in patients with Tuberculous Meningitis: A Prospective Evaluation

Lower yield of available diagnostic tests for tuberculous meningitis (TBM) frequently causes delay in diagnosis. Recently, 18F-fluorodeoxyglucose positron emission tomography (FDG PET) has been used in infectious disorders such as pulmonary tuberculosis; however, it is rarely used in TBM. This study was aimed to ascertain the role of FDG PET in the diagnosis and determination of the extent of disease and prognosis in patients with TBM. After excluding unsuitable patients, 25 patients were subjected to whole-body PET-computed tomography (CT) image acquisition along with separate brain protocol with an integrated PET-CT device. FDG PET was found to be abnormal in 92% patients. Extracranial FDG uptake was observed in 80% patients. Most common extracranial site of involvement was lymph nodes (60%), followed by lung (56%), vertebral body (8%), genitourinary organs (8%), and spleen (4%). FDG PET observed extracranial involvement had 80% sensitivity and 20% specificity in detecting definite TBM cases. In conclusion, FDG PET may be a useful test in TBM evaluation.

Real-time Polymerase Chain Reaction for Mycobacterium tuberculosis Meningitis is More Sensitive in Patients with HIV Co-Infection

BACKGROUND

Tuberculous meningitis (TbM) is the most severe complication of extra pulmonary tuberculosis (Tb). There is a higher frequency of positive cerebrospinal fluid (CSF) cultures for Mycobacterium tuberculosis (MTb) in samples from human immunodeficiency virus (HIV) co-infected patients than in those from HIV-negative patients. We hypothesized that real time PCR assays for MTb (MTb qPCR) using CSF would be more sensitive in HIV co-infected patients owing to a greater MTb burden. The present study aimed to verify the diagnostic performance of MTb qPCR in CSF of TbM patients who either were co-infected with HIV or were HIVnegative.

METHODS

A total of 334 consecutive participants with suspected TbM were divided into two groups: HIV co-infected and HIV-negative; each group was categorized into definite TbM, probable TbM, possible TbM, and TbM-negative subgroups based on clinical, laboratory and imaging data. We evaluated the diagnostic characteristics of MTb qPCR analysis to detect TbM in CSF by comparing the results to those obtained for definite TbM (i.e., positive MTb culture) and/or probable TbM in CSF, as gold standard.

RESULTS

The sensitivity of MTb qPCR in the definite and probable subgroups of the HIV coinfected participants (n = 14) was 35.7%, with a specificity of 93.8%, negative predictive value (NPV) of 94.4%, and negative clinical utility index (CUI-) of 0.89. Results of the HIV-negative group (n = 7) showed lower sensitivity (14.3%) and similar specificity, NPV, and CUI-.

CONCLUSION

The findings confirmed our hypothesis, despite the low sensitivity. MTb qPCR may significantly contribute to diagnosis when associated with clinical criteria and complementary examinations.

The association between serum sodium level and tuberculous meningitis compared with viral and bacterial meningitis

We evaluated the association between hyponatremia and tuberculous meningitis (TBM) with the aim of providing additional information for differential diagnosis from other types of infectious meningitis, especially viral meningitis (VM). Cross-sectional and longitudinal data involving 5026 participants older than 18 years were analyzed in the total population and a propensity-matched population. The initial and lowest sodium levels and longitudinal changes in TBM, bacterial meningitis (BM), and VM patients were compared. Participants in the TBM group were enrolled when they were diagnosed as possible, probable, or definite TBM according to the Marais' criteria. The initial serum sodium level was significantly lower in TBM patients than in BM and VM patients (136.9 ± 5.9 vs. 138.3 ± 4.7 mmol/L, p < 0.001 for TBM vs. BM, and 139.0 ± 3.1, p < 0.001 for TBM vs. VM), and it decreased significantly more steeply to lower levels in both the TBM and BM patients compared with VM patients. The lowest serum sodium level was in the order of TBM < BM < VM patients, and the change was statistically significant in all subgroups (131.8 ± 6.4, 133.1 ± 5.1, 137.4 ± 3.7, respectively, p < 0.001). Participants with lower serum sodium level were more likely to have a diagnosis of TBM rather than VM, and this association was more pronounced for the lowest sodium level than the initial sodium level [OR 4.6 (95% CI 2.4-8.8, p < 0.001)]. These findings indicate that baseline and longitudinal evaluation of serum sodium level can provide information for differential diagnosis of TBM from BM or VM.

Feasibility and usefulness of tele-follow-up in the patients with tuberculous meningitis

Background

Tuberculous meningitis (TBM) is the most severe form of tuberculosis and these patients need close follow-up because of a high frequency of complications. The coronavirus disease 2019 pandemic and lockdown resulted in an interruption in physical follow-up. In this situation, tele-follow-up may be helpful. We report the feasibility and usefulness of a telephonic follow-up in patients with TBM.

Methods

Patients with TBM managed by us from January 2017 to March 2020 were included from the TBM registry. Their presenting symptoms, and clinical and investigation findings were noted. We contacted these patients telephonically and their clinical status was obtained using a questionnaire. Based on the telephonic information, outcomes were categorized as death, poor or good. Patients with the new medical problems were advised as to relevant investigations and the reports were obtained through WhatsApp for prescribing treatment.

Results

The telephone numbers of 103 of 144 (71.5%) patients were viable. Twenty-seven (26.2%) patients died, 15 (19.7%) had a poor outcome and 61 (80.2%) had a good outcome. Twenty-five (32.9%) patients had new medical problems: 18 TBM related and 7 TBM unrelated. The medical problems of 23 patients could be managed telephonically and only 3 (4%) patients needed a physical visit. Sixty-five (85.5%) patients happily answered the questionnaire and willing responders needed a treatment modification more frequently than the reluctant responders (p=0.008). Patients on active antitubercular treatment needed treatment modification more frequently (80% vs 21.3%).

Conclusions

Tele-follow-up is feasible in 96% of TBM patients and is beneficial, cost effective and overcomes the barrier of distance.

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.

Defeating Paediatric Tuberculous Meningitis: Applying the WHO "Defeating Meningitis by 2030: Global Roadmap"

Children affected by tuberculous meningitis (TBM), as well as their families, have needs that lie at the intersections between the tuberculosis and meningitis clinical, research, and policy spheres. There is therefore a substantial risk that these needs are not fully met by either programme. In this narrative review article, we use the World Health Organization (WHO) “Defeating Meningitis by 2030: global roadmap” as a starting point to consider key goals and activities to specifically defeat TBM in children. We apply the five pillars outlined in the roadmap to describe how this approach can be adapted to serve children affected by TBM. The pillars are (i) prevention; (ii) diagnosis and treatment; (iii) surveillance; (iv) support and care for people affected by meningitis; and (v) advocacy and engagement. We conclude by calling for greater integration between meningitis and TB programmes at WHO and at national levels.

Comparative analysis between tuberculous meningitis and other forms of extrapulmonary tuberculosis

Introduction

Tuberculosis is a multisystem disease that may affect any organ or tissue. Tuberculous meningitis (TBM) is the most severe form of tuberculosis and commonly affects the brain. We aimed to study the epidemiological, clinical, therapeutic and evolutionary features of TBM among adults and to compare them with other forms of extrapulmonary tuberculosis.

Methods

We conducted a retrospective study including all patients hospitalized for extrapulmonary tuberculosis in the infectious disease department in Sfax, Tunisia between 1993 and 2018. We specified the particularities of TBM cases, and we compared them with other extrapulmonary tuberculosis cases.

Results

We encountered 78 patients diagnosed with TBM, among 519 patients with extrapulmonary tuberculosis (15%). The median age was 36 years (23-50) years. There were 44 females (56.4%). In comparison with other forms of extrapulmonary tuberculosis, fever [odds ratio (OR)=4.4; p<0.001], asthenia (OR=3.4; p<0.001) and anorexia (OR=2.3; p=0.001) were significantly more frequent in TBM patients. Adverse effects of antitubercular therapy were more frequent among TBM patients (OR=3.1; p<0.001). The mean duration of antitubercular therapy was 15 (12-20) months. Recovery occurred in 66 cases (84.6%), complications in 44 cases (56.4%) and death in 7 cases (9%). Comparison of the disease evolution showed that complications (OR=7.4; p<0.001) and mortality rates (OR=10.7; p<0.001) were significantly more frequent in TBM patients, while recovery was significantly more frequent in other sites of extrapulmonary tuberculosis patients (OR=0.5; p=0.02).

Conclusions

In our country, TBM remains a disabling disease. Despite antitubercular therapy, the prognosis was more severe with the occurrence of not only complications but also a high mortality rate in comparison with other forms of extrapulmonary tuberculosis. When clinical and laboratory features suggest the diagnosis of TBM, clinicians should look for tuberculosis elsewhere in the body.

MR vessel wall imaging in tubercular meningitis

PURPOSE

Tubercular meningitis (TBM) has the propensity to cause secondary vasculitis through various mechanisms leading to development of cerebrovascular complications. These vascular involvements can be detected by vessel wall imaging (VWI). In this study, we aimed to study detailed findings of vessel wall imaging in cases of tubercular meningitis.

METHODS

All consecutive patients of suspected tubercular meningitis in whom diagnosis of TBM could be made according to diagnostic criteria given by Ahuja et al. were included in the study. High-resolution MR VWI and time of flight (TOF) magnetic resonance angiography (MRA) were done along with routine MRI sequences. Arteries up to second-order branches were studied, and statistical analyses were done with respect to stage of tubercular meningitis, infarctions and TOF MRA findings.

RESULTS

Out of all 101 cases of TBM, infarctions were found in 49 cases (48.5%), and vessel wall enhancement was seen in 67 cases (66.3%). With increasing severity of disease, more severe vascular involvement was seen on VWI. There was significant association between enhancement of individual arteries and infarctions in their territories. VWI had better sensitivity than the MRA, while MRA had better specificity than VWI for detection of vascular complications.

CONCLUSION

Tubercular vasculitis can be detected by VWI in the form of nodular or smooth segmental enhancement of vessel wall with or without stenosis. Incorporation of VWI in routine MR imaging can play a greater role in early detection and management of cerebrovascular complications which can help to improve prognosis of the disease.

Tuberculous Meningitis: Pathogenesis, Immune Responses, Diagnostic Challenges, and the Potential of Biomarker-Based Approaches

Tuberculous meningitis (TBM) is the most devastating form of tuberculosis (TB), causing high mortality or disability. Clinical management of the disease is challenging due to limitations of the existing diagnostic approaches. Our knowledge on the immunology and pathogenesis of the disease is currently limited. More research is urgently needed to enhance our understanding of the immunopathogenesis of the disease and guide us toward the identification of targets that may be useful for vaccines or host-directed therapeutics.

Tuberculous meningitis (TBM) is the most devastating form of tuberculosis (TB), causing high mortality or disability. Clinical management of the disease is challenging due to limitations of the existing diagnostic approaches. Our knowledge on the immunology and pathogenesis of the disease is currently limited. More research is urgently needed to enhance our understanding of the immunopathogenesis of the disease and guide us toward the identification of targets that may be useful for vaccines or host-directed therapeutics. In this review, we summarize the current knowledge about the immunology and pathogenesis of TBM and summarize the literature on existing and new, especially biomarker-based, approaches that may be useful in the management of TBM. We identify research gaps and provide directions for research which may lead to the development of new tools for the control of the disease in the near future.

Caloric Restriction Promotes Immunometabolic Reprogramming Leading to Protection from Tuberculosis

There is a strong relationship between metabolic state and susceptibility to Mycobacterium tuberculosis (MTB) infection, with energy metabolism setting the basis for an exaggerated immuno-inflammatory response, which concurs with MTB pathogenesis. Herein, we show that controlled caloric restriction (CR), not leading to malnutrition, protects susceptible DBA/2 mice against pulmonary MTB infection by reducing bacterial load, lung immunopathology, and generation of foam cells, an MTB reservoir in lung granulomas. Mechanistically, CR induced a metabolic shift toward glycolysis, and decreased both fatty acid oxidation and mTOR activity associated with induction of autophagy in immune cells. An integrated multi-omics approach revealed a specific CR-induced metabolomic, transcriptomic, and proteomic signature leading to reduced lung damage and protective remodeling of lung interstitial tightness able to limit MTB spreading. Our data propose CR as a feasible immunometabolic manipulation to control MTB infection, and this approach offers an unexpected strategy to boost immunity against MTB.

Xpert MTB/RIF Ultra and Xpert MTB/RIF assays for extrapulmonary tuberculosis and rifampicin resistance in adults

BACKGROUND

Xpert MTB/RIF Ultra (Xpert Ultra) and Xpert MTB/RIF are World Health Organization (WHO)-recommended rapid nucleic acid amplification tests (NAATs) widely used for simultaneous detection of Mycobacterium tuberculosis complex and rifampicin resistance in sputum. To extend our previous review on extrapulmonary tuberculosis (Kohli 2018), we performed this update to inform updated WHO policy (WHO Consolidated Guidelines (Module 3) 2020).

OBJECTIVES

To estimate diagnostic accuracy of Xpert Ultra and Xpert MTB/RIF for extrapulmonary tuberculosis and rifampicin resistance in adults with presumptive extrapulmonary tuberculosis.

SEARCH METHODS

Cochrane Infectious Diseases Group Specialized Register, MEDLINE, Embase, Science Citation Index, Web of Science, Latin American Caribbean Health Sciences Literature, Scopus, ClinicalTrials.gov, the WHO International Clinical Trials Registry Platform, the International Standard Randomized Controlled Trial Number Registry, and ProQuest, 2 August 2019 and 28 January 2020 (Xpert Ultra studies), without language restriction.

SELECTION CRITERIA

Cross-sectional and cohort studies using non-respiratory specimens. Forms of extrapulmonary tuberculosis: tuberculous meningitis and pleural, lymph node, bone or joint, genitourinary, peritoneal, pericardial, disseminated tuberculosis. Reference standards were culture and a study-defined composite reference standard (tuberculosis detection); phenotypic drug susceptibility testing and line probe assays (rifampicin resistance detection).

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted data and assessed risk of bias and applicability using QUADAS-2. For tuberculosis detection, we performed separate analyses by specimen type and reference standard using the bivariate model to estimate pooled sensitivity and specificity with 95% credible intervals (CrIs). We applied a latent class meta-analysis model to three forms of extrapulmonary tuberculosis. We assessed certainty of evidence using GRADE.

MAIN RESULTS

69 studies: 67 evaluated Xpert MTB/RIF and 11 evaluated Xpert Ultra, of which nine evaluated both tests. Most studies were conducted in China, India, South Africa, and Uganda. Overall, risk of bias was low for patient selection, index test, and flow and timing domains, and low (49%) or unclear (43%) for the reference standard domain. Applicability for the patient selection domain was unclear for most studies because we were unsure of the clinical settings. Cerebrospinal fluid Xpert Ultra (6 studies) Xpert Ultra pooled sensitivity and specificity (95% CrI) against culture were 89.4% (79.1 to 95.6) (89 participants; low-certainty evidence) and 91.2% (83.2 to 95.7) (386 participants; moderate-certainty evidence). Of 1000 people where 100 have tuberculous meningitis, 168 would be Xpert Ultra-positive: of these, 79 (47%) would not have tuberculosis (false-positives) and 832 would be Xpert Ultra-negative: of these, 11 (1%) would have tuberculosis (false-negatives). Xpert MTB/RIF (30 studies) Xpert MTB/RIF pooled sensitivity and specificity against culture were 71.1% (62.8 to 79.1) (571 participants; moderate-certainty evidence) and 96.9% (95.4 to 98.0) (2824 participants; high-certainty evidence). Of 1000 people where 100 have tuberculous meningitis, 99 would be Xpert MTB/RIF-positive: of these, 28 (28%) would not have tuberculosis; and 901 would be Xpert MTB/RIF-negative: of these, 29 (3%) would have tuberculosis. Pleural fluid Xpert Ultra (4 studies) Xpert Ultra pooled sensitivity and specificity against culture were 75.0% (58.0 to 86.4) (158 participants; very low-certainty evidence) and 87.0% (63.1 to 97.9) (240 participants; very low-certainty evidence). Of 1000 people where 100 have pleural tuberculosis, 192 would be Xpert Ultra-positive: of these, 117 (61%) would not have tuberculosis; and 808 would be Xpert Ultra-negative: of these, 25 (3%) would have tuberculosis. Xpert MTB/RIF (25 studies) Xpert MTB/RIF pooled sensitivity and specificity against culture were 49.5% (39.8 to 59.9) (644 participants; low-certainty evidence) and 98.9% (97.6 to 99.7) (2421 participants; high-certainty evidence). Of 1000 people where 100 have pleural tuberculosis, 60 would be Xpert MTB/RIF-positive: of these, 10 (17%) would not have tuberculosis; and 940 would be Xpert MTB/RIF-negative: of these, 50 (5%) would have tuberculosis. Lymph node aspirate Xpert Ultra (1 study) Xpert Ultra sensitivity and specificity (95% confidence interval) against composite reference standard were 70% (51 to 85) (30 participants; very low-certainty evidence) and 100% (92 to 100) (43 participants; low-certainty evidence). Of 1000 people where 100 have lymph node tuberculosis, 70 would be Xpert Ultra-positive and 0 (0%) would not have tuberculosis; 930 would be Xpert Ultra-negative and 30 (3%) would have tuberculosis. Xpert MTB/RIF (4 studies) Xpert MTB/RIF pooled sensitivity and specificity against composite reference standard were 81.6% (61.9 to 93.3) (377 participants; low-certainty evidence) and 96.4% (91.3 to 98.6) (302 participants; low-certainty evidence). Of 1000 people where 100 have lymph node tuberculosis, 118 would be Xpert MTB/RIF-positive and 37 (31%) would not have tuberculosis; 882 would be Xpert MTB/RIF-negative and 19 (2%) would have tuberculosis. In lymph node aspirate, Xpert MTB/RIF pooled specificity against culture was 86.2% (78.0 to 92.3), lower than that against a composite reference standard. Using the latent class model, Xpert MTB/RIF pooled specificity was 99.5% (99.1 to 99.7), similar to that observed with a composite reference standard. Rifampicin resistance Xpert Ultra (4 studies) Xpert Ultra pooled sensitivity and specificity were 100.0% (95.1 to 100.0), (24 participants; low-certainty evidence) and 100.0% (99.0 to 100.0) (105 participants; moderate-certainty evidence). Of 1000 people where 100 have rifampicin resistance, 100 would be Xpert Ultra-positive (resistant): of these, zero (0%) would not have rifampicin resistance; and 900 would be Xpert Ultra-negative (susceptible): of these, zero (0%) would have rifampicin resistance. Xpert MTB/RIF (19 studies) Xpert MTB/RIF pooled sensitivity and specificity were 96.5% (91.9 to 98.8) (148 participants; high-certainty evidence) and 99.1% (98.0 to 99.7) (822 participants; high-certainty evidence). Of 1000 people where 100 have rifampicin resistance, 105 would be Xpert MTB/RIF-positive (resistant): of these, 8 (8%) would not have rifampicin resistance; and 895 would be Xpert MTB/RIF-negative (susceptible): of these, 3 (0.3%) would have rifampicin resistance.

AUTHORS' CONCLUSIONS

Xpert Ultra and Xpert MTB/RIF may be helpful in diagnosing extrapulmonary tuberculosis. Sensitivity varies across different extrapulmonary specimens: while for most specimens specificity is high, the tests rarely yield a positive result for people without tuberculosis. For tuberculous meningitis, Xpert Ultra had higher sensitivity and lower specificity than Xpert MTB/RIF against culture. Xpert Ultra and Xpert MTB/RIF had similar sensitivity and specificity for rifampicin resistance. Future research should acknowledge the concern associated with culture as a reference standard in paucibacillary specimens and consider ways to address this limitation.

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.

Value of next-generation sequencing in early diagnosis of patients with tuberculous meningitis

OBJECTIVES

To assess the value of next-generation sequencing (NGS) technology in early diagnosis of patients with tuberculous meningitis (TBM).

METHODS

56 patients with clinically suspected TBM who came to Shandong Provincial Chest Hospital from February 2, 2018 to August 2, 2018 were prospectively included, and the clinical diagnosis and treatment outcomes were followed up. NGS was performed for the cerebrospinal fluid specimens submitted for test on the BGISEQ-100 platform of Tianjin Huada Gene Research Institute and the obtained pathogen sequences were compared with the pathogen data to get the final results. The NGS results were positive for detecting the unique matching sequence of the Mycobacterium tuberculosis (MTB) complex and negative for no unique matching sequence. Patients confirmed with TBM should have at least one of the following four items: cerebrospinal fluid MTB culture positive, smear positive, Xpert MTB/RIF test positive, or MTB nucleic acid polymerase chain reaction (PCR) test positive; clinically diagnosed patients were those with clinically suspected TBM and effective anti-tuberculosis treatment; non-TBM patients were those with other pathogenic basis or clinical exclusion of TBM. The sensitivity and specificity of NGS in early diagnosis of TBM were analyzed.

RESULTS

22 patients were confirmed with TBM, of which 13 were positive for Xpert MTB/RIF test, 6 were positive for cerebrospinal fluid MTB culture, 5 were positive for MTB nucleic acid PCR test, 12 patients were clinically diagnosed with TBM, and there were 16 cases of non-TBM patients. Among confirmed and clinically diagnosed patients, 20 cases of MTB complex were detected by NGS technology, with a sensitivity of 58.8% (20/34) and specificity of 100% (16/16). Among confirmed patients, the sensitivity of NGS was 63.6% (14/22). Of the 50 specimens that were simultaneously subjected to traditional methods, Xpert MTB/RIF test and NGS, the specificity of the three methods was 100% (16/16) based on clinical diagnosis, and the sensitivity was 29.4% (10/34), 38.2% (13/34), and 58.8% (20/34) respectively. The difference of sensitivity between the first two detection methods and NGS was statistically significant (McNemar test, p = 0.013, x² = 5.786 and p = 0.065, x² = 3.273). The sensitivity of traditional methods combined with NGS was as high as 82.4% (28/34).

CONCLUSIONS

NGS technology could rapidly detect the MTB complex in cerebrospinal fluid with significant sensitivity and specificity, which could be used as an early diagnosis index of TBM. NGS combined with MTB culture could increase the detection rate.

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.

The diagnosis of tuberculous meningitis in adults and adolescents: protocol for a systematic review and individual patient data meta-analysis to inform a multivariable prediction model

Background: Tuberculous meningitis (TBM) is the most lethal and disabling form of tuberculosis. Delayed diagnosis and treatment, which is a risk factor for poor outcome, is caused in part by lack of availability of diagnostic tests that are both rapid and accurate. Several attempts have been made to develop clinical scoring systems to fill this gap, but none have performed sufficiently well to be broadly implemented. We aim to identify and validate a set of clinical predictors that accurately classify TBM using individual patient data (IPD) from published studies. Methods: We will perform a systematic review and obtain IPD from studies published from the year 1990 which undertook diagnostic testing for TBM in adolescents or adults using at least one of, microscopy for acid-fast bacilli, commercial nucleic acid amplification test for Mycobacterium tuberculosis or mycobacterial culture of cerebrospinal fluid.  Clinical data that have previously been shown to be associated with TBM, and can inform the final diagnosis, will be requested. The data-set will be divided into training and test/validation data-sets for model building. A predictive logistic model will be built using a training set with patients with definite TBM and no TBM. Should it be warranted, factor analysis may be employed, depending on evidence for multicollinearity or the case for including latent variables in the model. Discussion: We will systematically identify and extract key clinical parameters associated with TBM from published studies and use a 'big data' approach to develop and validate a clinical prediction model with enhanced generalisability. The final model will be made available through a smartphone application. Further work will be external validation of the model and test of efficacy in a randomised controlled trial.

The diagnosis of tuberculous meningitis in adults and adolescents: protocol for a systematic review and individual patient data meta-analysis to inform a multivariable prediction model

Background: Tuberculous meningitis (TBM) is the most lethal and disabling form of tuberculosis. Delayed diagnosis and treatment, which is a risk factor for poor outcome, is caused in part by lack of availability of diagnostic tests that are both rapid and accurate. Several attempts have been made to develop clinical scoring systems to fill this gap, but none have performed sufficiently well to be broadly implemented. We aim to identify and validate a set of clinical predictors that accurately classify TBM using individual patient data (IPD) from published studies. Methods: We will perform a systematic review and obtain IPD from studies published from the year 1990 which undertook diagnostic testing for TBM in adolescents or adults using at least one of, microscopy for acid-fast bacilli, commercial nucleic acid amplification test for Mycobacterium tuberculosis or mycobacterial culture of cerebrospinal fluid.  Clinical data that have previously been shown to be associated with TBM, and can inform the final diagnosis, will be requested. The data-set will be divided into training and test/validation data-sets for model building. A predictive logistic model will be built using a training set with patients with definite TBM and no TBM. Should it be warranted, factor analysis may be employed, depending on evidence for multicollinearity or the case for including latent variables in the model. Discussion: We will systematically identify and extract key clinical parameters associated with TBM from published studies and use a 'big data' approach to develop and validate a clinical prediction model with enhanced generalisability. The final model will be made available through a smartphone application. Further work will be external validation of the model and test of efficacy in a randomised controlled trial.

The global burden of tuberculous meningitis in adults: A modelling study

Tuberculous meningitis (TBM) is the most lethal form of tuberculosis. The incidence and mortality of TBM is unknown due to diagnostic challenges and limited disaggregated reporting of treated TBM by existing surveillance systems. We aimed to estimate the incidence and mortality of TBM in adults (15+ years) globally. Using national surveillance data from Brazil, South Africa, the United Kingdom, the United States of America, and Vietnam, we estimated the fraction of reported tuberculosis that is TBM, and the case fatality ratios for treated TBM in each of these countries. We adjusted these estimates according to findings from a systematic review and meta-analysis and applied them to World Health Organization tuberculosis notifications and estimates to model the global TBM incidence and mortality. Assuming the case detection ratio (CDR) for TBM was the same as all TB, we estimated that in 2019, 164,000 (95% UI; 129,000-199,000) adults developed TBM globally; 23% were among people living with HIV. Almost 60% of incident TBM occurred in males and 20% were in adults 25-34 years old. 70% of global TBM incidence occurred in Southeast Asia and Africa. We estimated that 78,200 (95% UI; 52,300-104,000) adults died of TBM in 2019, representing 48% of incident TBM. TBM case fatality in those treated was on average 27%. Sensitivity analysis assuming improved detection of TBM compared to other forms of TB (CDR odds ratio of 2) reduced estimated global mortality to 54,900 (95% UI; 32,200-77,700); assuming instead worse detection for TBM (CDR odds ratio of 0.5) increased estimated mortality to 125,000 (95% UI; 88,800-161,000). Our results highlight the need for improved routine TBM monitoring, especially in high burden countries. Reducing TBM incidence and mortality will be necessary to achieve the End TB Strategy targets.

Recapitulating the Bayesian framework for neurosurgical outpatient care and a cost-benefit analysis of telemedicine for socioeconomically disadvantaged patients in the Philippines during the pandemic

OBJECTIVE

In the Philippines during recent months, a neurosurgical center that caters primarily to socioeconomically disadvantaged patients has encountered unprecedented changes in practice patterns brought about by the COVID-19 pandemic. In particular, the usual task of outpatient care has shifted to the telemedicine format, bringing along all of its attendant advantages and gargantuan challenges. The authors sought to determine the responsiveness of this telemedicine setup to the needs of their disadvantaged patients and explored the application of Bayesian inference to enhance the use of teleconsultation in daily clinical decision-making.

METHODS

The authors used the following methods to assess the telemedicine setup used in a low-resource setting during the pandemic: 1) a cross-sectional survey of patients who participated in a medical consultation via telemedicine during the 16-week period from March 16, 2020, to July 15, 2020; 2) a cost-benefit analysis of the use of telemedicine by patients; and 3) a case illustration of a Bayesian approach application unique to the teleconsultation scenario.

RESULTS

Of the 272 patient beneficiaries of telemedicine in a 16-week period, 57 responded to the survey. The survey responses regarding neurosurgical outpatient care through telemedicine yielded high ratings of utility for the patients and their caregivers. According to 64% of respondents, the affordability of the telemedicine setup also prevented them from borrowing money from others, among other adverse life events prevented. There were realized financial gains on the part of the patients in terms of cost savings and protection from further impoverishment. The benefit-cost ratio was 3.51 for the patients, signifying that the benefits outweighed the costs. An actual teleconsultation case vignette was reported that is meant to be instructive and contributory to the preparedness of the neurosurgeon on the provider end of the service delivery.

CONCLUSIONS

Telemedicine holds promise as a viable and safe method for health service delivery during the pandemic. In the setting of a health system that is continually challenged by shortages of resources, this study shows that an effective telemedicine setup can come with high benefit-cost ratios and quality of care, along with the assurance of patient satisfaction. The potential for high-quality care can be enhanced by the inclusion of the Bayesian framework to the basic toolkit of remote clinical assessment. When confronted with choices in terms of differential diagnosis and tests, the rigor of a simple application of the Bayesian framework can minimize costs arising from uncertainties.

Tuberculous Otitis Media Complicated by Meningitis-Induced Bilateral Sensorineural Hearing Loss: A Case Report

Tuberculosis of the middle ear is a rare but treatable disease; however, delays in diagnosis and treatment usually lead to complications. Diagnosis is made difficult by most physicians being unfamiliar with the typical presenting features and special cultural and pathologic studies being required for diagnosis. A case report and literature review are presented, illustrating typical clinical, epidemiologic, and laboratory features, as well as complications and the treatment of tuberculous otitis media.

Metagenomic next generation sequencing for the diagnosis of tuberculosis meningitis: A systematic review and meta-analysis

Background

Tuberculous meningitis (TBM) is a severe form of extrapulmonary tuberculosis and its early diagnosis is very difficult leading to present with severe disability or die. The current study aimed to assess the accuracy of metagenomic next generation sequencing (mNGS) for TBM, and to identify a new test for the early diagnosis of TBM.

Methods

We searched for articles published in Embase, PubMed, Cochrane Library, China National Knowledge Infrastructure, and Wanfang Data up to June 30, 2020 for studies that assessed the efficacy of mNGS for the diagnosis of TBM. Then, the accuracy between mNGS and a composite reference standard (CRS) in these articles was compared using the meta-analysis approach.

Results

Four independent studies with 342 samples comparing mNGS and a CRS were included in this study. The sensitivity of mNGS for TBM diagnosis ranged from 27% to 84%. The combined sensitivity of mNGS was 61%, and the I² value was 92%. Moreover, the specificity of mNGS for TBM diagnosis ranged from 96% to 100%. The combined specificity of mNGS was 98%, and the I² value was 74%. The heterogeneity between studies in terms of sensitivity and specificity was significant. The area under the curve (AUC) of the summary receiver operating characteristic curve (SROC) of mNGS for TBM was 0.98.

Conclusions

The sensitivity of mNGS for TBM diagnosis was moderate. Furthermore, the specificity was extremely high, and the AUC of the SROC indicated a very good diagnostic efficacy. mNGS could be used as an early diagnostic method for TBM, however, the results should be treated with caution for the heterogeneity between studies was extremely significant.

Systematic review registration

INPLASY202070100.

Clinical features of adult patients with a definite diagnosis of central nervous system tuberculosis in an endemic country: A 13-year retrospective review

Rationale

Objectives

Methods

Measurements and main results

Conclusions

Model-Based Meta-analysis of Rifampicin Exposure and Mortality in Indonesian Tuberculous Meningitis Trials

BACKGROUND

Intensified antimicrobial treatment with higher rifampicin doses may improve outcome of tuberculous meningitis, but the desirable exposure and necessary dose are unknown. Our objective was to characterize the relationship between rifampicin exposures and mortality in order to identify optimal dosing for tuberculous meningitis.

METHODS

An individual patient meta-analysis was performed on data from 3 Indonesian randomized controlled phase 2 trials comparing oral rifampicin 450 mg (~10 mg/kg) to intensified regimens including 750-1350 mg orally, or a 600-mg intravenous infusion. Pharmacokinetic data from plasma and cerebrospinal fluid (CSF) were analyzed with nonlinear mixed-effects modeling. Six-month survival was described with parametric time-to-event models.

RESULTS

Pharmacokinetic analyses included 133 individuals (1150 concentration measurements, 170 from CSF). The final model featured 2 disposition compartments, saturable clearance, and autoinduction. Rifampicin CSF concentrations were described by a partition coefficient (5.5%; 95% confidence interval [CI], 4.5%-6.4%) and half-life for distribution plasma to CSF (2.1 hours; 95% CI, 1.3-2.9 hours). Higher CSF protein concentration increased the partition coefficient. Survival of 148 individuals (58 died, 15 dropouts) was well described by an exponentially declining hazard, with lower age, higher baseline Glasgow Coma Scale score, and higher individual rifampicin plasma exposure reducing the hazard. Simulations predicted an increase in 6-month survival from approximately 50% to approximately 70% upon increasing the oral rifampicin dose from 10 to 30 mg/kg, and predicted that even higher doses would further improve survival.

CONCLUSIONS

Higher rifampicin exposure substantially decreased the risk of death, and the maximal effect was not reached within the studied range. We suggest a rifampicin dose of at least 30 mg/kg to be investigated in phase 3 clinical trials.

Presentations and outcomes of central nervous system TB in a UK cohort: The high burden of neurological morbidity

OBJECTIVES

Most data for Central Nervous System Tuberculosis (CNS-TB) derive from high-incidence, resource-limited countries. We sought to determine the presentation, management and outcomes of CNS-TB in a low-incidence setting with accessible healthcare.

METHODS

We undertook a retrospective, observational study of CNS-TB in adults at a single tertiary-referral London hospital (2001-2017). Cases were categorised as either TB meningitis (TBM) or TB mass lesions without meningitis (TBML), applying novel criteria for definite, probable, and possible TBML.

RESULTS

We identified sixty-two cases of TBM (37% definite; 31% probable; 32% possible) alongside 14 TBML cases (36% definite; 29% probable; and 36% possible). Clinical presentation was highly variable. Among CSF parameters, hypoglycorrhachia proved most discriminatory for "definite" TBM. Neurosurgical intervention was required for mass-effect or hydrocephalus in 16%. Mortality was higher in TBM versus TBML (16% vs. 0%) but overall morbidity was significant; 33% of TBM and 29% of TBML survivors suffered persisting neurological disability at 12-months. In TBM, hydrocephalus, infarct, basal enhancement and low CSF white cell count were independently associated with worse neurological outcomes.

CONCLUSION

Although mortality was lower than previously reported in other settings, morbidity was significant, highlighting the need for improved CNS-TB diagnostics, therapeutics and interventions to mitigate neurological sequelae.

Tumor necrosis factor antagonists for paradoxical inflammatory reactions in the central nervous system tuberculosis: Case report and review

RATIONALE

Paradoxical reaction/immune reconstitution inflammatory syndrome is common in patients with central nervous system tuberculosis. Management relies on high-dose corticosteroids and surgery when feasible.

PATIENT CONCERN

We describe 2 cases of HIV-negative patients with corticosteroid-refractory paradoxical reactions of central nervous system tuberculosis.

DIAGNOSES

The 2 patients experienced clinical impairment shortly after starting therapy for TB, and magnetic resonance imaging showed the presence of tuberculomas, leading to the diagnosis of a paradoxical reaction.

INTERVENTIONS

We added infliximab, an anti-tumor necrosis factor (TNF)-alpha monoclonal antibody, to the dexamethasone.

OUTCOMES

Both patients had favorable outcomes, 1 achieving full recovery but 1 suffering neurologic sequelae.

LESSONS

Clinicians should be aware of the risk of paradoxical reactions/immune reconstitution inflammatory syndrome when treating patients with tuberculosis of the central nervous system and should consider the prompt anti-TNF-α agents in cases not responding to corticosteroids.

Disseminated Mycobacterium bovis Infection Complicated by Meningitis and Stroke: A Case Report

We describe a case of a 19-year-old female presenting with Mycobacterium bovis meningitis, a rarely encountered infection. We discuss the use of pyrosequencing to aid in prompt diagnosis of M. bovis infection, as well as treatment strategies and challenges given the organism’s intrinsic resistance to pyrazinamide.

High dose oral rifampicin to improve survival from adult tuberculous meningitis: A randomised placebo-controlled double-blinded phase III trial (the HARVEST study)

Background: Tuberculous meningitis (TBM), the most severe form of tuberculosis (TB), results in death or neurological disability in >50%, despite World Health Organisation recommended therapy. Current TBM regimen dosages are based on data from pulmonary TB alone. Evidence from recent phase II pharmacokinetic studies suggests that high dose rifampicin (R) administered intravenously or orally enhances central nervous system penetration and may reduce TBM associated mortality. We hypothesize that, among persons with TBM, high dose oral rifampicin (35 mg/kg) for 8 weeks will improve survival compared to standard of care (10 mg/kg), without excess adverse events.

Protocol: We will perform a parallel group, randomised, placebo-controlled, double blind, phase III multicentre clinical trial comparing high dose oral rifampicin to standard of care. The trial will be conducted across five clinical sites in Uganda, South Africa and Indonesia. Participants are HIV-positive or negative adults with clinically suspected TBM, who will be randomised (1:1) to one of two arms: 35 mg/kg oral rifampicin daily for 8 weeks (in combination with standard dose isoniazid [H], pyrazinamide [Z] and ethambutol [E]) or standard of care (oral HRZE, containing 10 mg/kg/day rifampicin). The primary end-point is 6-month survival. Secondary end points are: i) 12-month survival ii) functional and neurocognitive outcomes and iii) safety and tolerability. Tertiary outcomes are: i) pharmacokinetic outcomes and ii) cost-effectiveness of the intervention. We will enrol 500 participants over 2.5 years, with follow-up continuing until 12 months post-enrolment.

Discussion: Our best TBM treatment still results in unacceptably high mortality and morbidity. Strong evidence supports the increased cerebrospinal fluid penetration of high dose rifampicin, however conclusive evidence regarding survival benefit is lacking. This study will answer the important question of whether high dose oral rifampicin conveys a survival benefit in TBM in HIV-positive and -negative individuals from Africa and Asia.

Trial registration: ISRCTN15668391 (17/06/2019)

High dose oral rifampicin to improve survival from adult tuberculous meningitis: A randomised placebo-controlled double-blinded phase III trial (the HARVEST study)

Background: Tuberculous meningitis (TBM), the most severe form of tuberculosis (TB), results in death or neurological disability in >50%, despite World Health Organisation recommended therapy. Current TBM regimen dosages are based on data from pulmonary TB alone. Evidence from recent phase II pharmacokinetic studies suggests that high dose rifampicin (R) administered intravenously or orally enhances central nervous system penetration and may reduce TBM associated mortality. We hypothesize that, among persons with TBM, high dose oral rifampicin (35 mg/kg) for 8 weeks will improve survival compared to standard of care (10 mg/kg), without excess adverse events. Protocol: We will perform a parallel group, randomised, placebo-controlled, double blind, phase III multicentre clinical trial comparing high dose oral rifampicin to standard of care. The trial will be conducted across five clinical sites in Uganda, South Africa and Indonesia. Participants are HIV-positive or negative adults with clinically suspected TBM, who will be randomised (1:1) to one of two arms: 35 mg/kg oral rifampicin daily for 8 weeks (in combination with standard dose isoniazid [H], pyrazinamide [Z] and ethambutol [E]) or standard of care (oral HRZE, containing 10 mg/kg/day rifampicin). The primary end-point is 6-month survival. Secondary end points are: i) 12-month survival ii) functional and neurocognitive outcomes and iii) safety and tolerability. Tertiary outcomes are: i) pharmacokinetic outcomes and ii) cost-effectiveness of the intervention. We will enrol 500 participants over 2.5 years, with follow-up continuing until 12 months post-enrolment. Discussion: Our best TBM treatment still results in unacceptably high mortality and morbidity. Strong evidence supports the increased cerebrospinal fluid penetration of high dose rifampicin, however conclusive evidence regarding survival benefit is lacking. This study will answer the important question of whether high dose oral rifampicin conveys a survival benefit in TBM in HIV-positive and -negative individuals from Africa and Asia. Trial registration: ISRCTN15668391 (17/06/2019).

Challenges in the diagnosis of tuberculous meningitis

Tuberculosis (TB) continues to pose a significant public health problem. Tuberculous meningitis (TBM) is the most severe form of extra-pulmonary TB. TBM carries a high mortality rate, including for those receiving treatment for TB. Diagnosis of TBM is difficult for clinicians as it can clinically present similarly to other forms of meningitis. The difficulty in diagnosis often leads to a delay in treatment and subsequent mortality. Those who survive are left with long-term sequelae leading to lifelong disability. The microbiologic diagnosis of TBM requires the isolation of Mycobacterium tuberculosis from the cerebrospinal fluid (CSF) of an infected patient. The diagnosis of tuberculous meningitis continues to be challenging for clinicians. Unfortunately, many cases of TBM cannot be confirmed based on clinical and imaging findings as the clinical findings are nonspecific, while laboratory techniques are largely insensitive or slow. Until recently, the lack of accessible and timely tests has contributed to a delay in diagnosis and subsequent morbidity and mortality for many patients, particularly those in resourcelimited settings. The availability of Xpert Ultra and point-of-care lipoarabinomannan (LAM) testing could represent a new era of prompt diagnosis and early treatment of tuberculous meningitis. However, clinicians must be cautious when ruling out TBM with Xpert Ultra due to its low negative predictive value. Due to the limitations of current diagnostics, clinicians should utilize a combination of diagnostic modalities in order to prevent morbidity in patients with TBM.

Recent Developments in Tuberculous Meningitis Pathogenesis and Diagnostics

The pathogenesis of Tuberculous meningitis (TBM) is poorly understood, but contemporary molecular biology technologies have allowed for recent improvements in our understanding of TBM. For instance, neutrophils appear to play a significant role in the immunopathogenesis of TBM, and either a paucity or an excess of inflammation can be detrimental in TBM. Further, severity of HIV-associated immunosuppression is an important determinant of inflammatory response; patients with the advanced immunosuppression (CD4+ T-cell count of <150 cells/μL) having higher CSF neutrophils, greater CSF cytokine concentrations and higher mortality than those with CD4+ T-cell counts > 150 cells/μL. Host genetics may also influence outcomes with LT4AH genotype predicting inflammatory phenotype, steroid responsiveness and survival in Vietnamese adults with TBM. Whist in Indonesia, CSF tryptophan level was a predictor of survival, suggesting tryptophan metabolism may be important in TBM pathogenesis. These varying responses mean that we must consider whether a "one-size-fits-all" approach to anti-bacillary or immunomodulatory treatment in TBM is truly the best way forward. Of course, to allow for proper treatment, early and rapid diagnosis of TBM must occur. Diagnosis has always been a challenge but the field of TB diagnosis is evolving, with sensitivities of at least 70% now possible in less than two hours with GeneXpert MTB/Rif Ultra. In addition, advanced molecular techniques such as CRISPR-MTB and metagenomic next generation sequencing may hold promise for TBM diagnosis. Host-based biomarkers and signatures are being further evaluated in childhood and adult TBM as adjunctive biomarkers as even with improved molecular assays, cases are still missed. A better grasp of host and pathogen behaviour may lead to improved diagnostics, targeted immunotherapy, and possibly biomarker-based, patient-specific treatment regimens.

Magnetic bead flocculation test: Improving the diagnosis of tuberculous meningitis (TBM) in low-resource settings

BACKGROUND

Despite several recent advances in detection techniques, there is still an unmet need for simple tests for the diagnosis of tuberculous meningitis (TBM). Therefore, in an effort towards developing a simple and rapid diagnostic test for resource-poor settings, we designed an assay in which magnetic bead flocculation test (MBF) was used to detect the amplified DNA. Multi-targeted (using two multicopy gene targets IS6110 and IS1081) loop-mediated isothermal amplification (MLAMP) was used for amplification.

METHODS

MLAMP-MBF assay was performed on CSF samples of 600 patients, out of which 120 were definite TBM (culture confirmed), 280 were probable TBM and 200 were non-TB controls, based on Marais's criteria. The performance of assay was evaluated by comparing the result of definite TBM with culture and that of probable TBM with composite reference standard consisting of clinical, microbiological(smear/culture) and radiological parameters.

RESULTS

The overall sensitivity of MLAMP-MBF (using any of the two gene targets) was 89.5% and specificity was 100%. The sensitivity was 96.6% (116/120) in diagnosing definite TBM and 86.4% (242/280) in diagnosing probable TBM. The sensitivity of IS1081 was 88% and that of IS6110 was 83% in diagnosing TBM. Specificity of both the gene targets was 100%. There were 20 cases positive only by IS1081 LAMP and 6 cases positive only by IS6110; thus 26 of 400 (6.5%) TBM cases could be additionally detected following multi-targeted approach.

CONCLUSION

MLAMP-MBF is a sensitive, robust, cost-effective and promising technique for diagnosis of TBM in low-resource high-endemic settings.

Derivation of a bedside score (MASH-P) to predict 6-month mortality in tuberculous meningitis

BACKGROUND

Tuberculous meningitis is commonly associated with a poor outcome. Simple bedside prognostic scores can help immensely in predicting the outcome.

MATERIALS AND METHOD

A total of 721 patients, from 5 of our previous studies, were included. With primary outcome measure as death, a prognostic model was derived using binary logistic regression. The model was assessed using discrimination and calibration, and internally validated using the bootstrap method. A bedside prognostic score was derived by rounding of the regression coefficients to the nearest integers.

RESULTS

A total of 126 (17.48%) patients died. The final model found that higher age, stage III disease, baseline MBI ≤ 12, papilledema and hydrocephalus were significant predictors of death. The final model showed good discrimination as evident by an AUC = 83.1% (95% confidence interval 79.5%-86.7%, P < .001) and good calibration (Hosmer and Lemeshow test P = .579). The model remained valid after internal validation by boot strapping. A simple bedside score with the acronym MASH-P to denote variables baseline MBI (M), age (A), stage (S), hydrocephalus (H) and papilledema (P), was thus derived. The score can range from 0 to 10. Higher the score, higher is the probability of death; a score of 0 carries a predicted probability of just 1.7% while a score of 10 corresponds to a predicted probability of 65%. An electronic ready reckoner has also been developed to aid prognostication on the go.

CONCLUSION

MASH-P is a simple prognostic scoring model that can be used at bedside and aid in decision making as well as counselling.

Metagenomic Next-Generation Sequencing (mNGS) in cerebrospinal fluid for rapid diagnosis of Tuberculosis meningitis in HIV-negative population

OBJECTIVE

Metagenomic Next-Generation Sequencing (mNGS) has been applied as a novel method of detection pathogens for infectious diseases, but its value in the rapid diagnosis of tuberculous meningitis(TBM)has not been clarified based on large samples.

METHODS

A retrospective analysis was conducted on 51 inpatients with suspected TBM who underwent mNGS and four other tests in cerebrospinal fluid (CSF).

RESULTS

Among 51 included patients, 45 cases were diagnosed as TBM (38 definite, 5 probable, 2 possible) and 6 cases as non-TBM. Using final diagnosis as reference standard, the sensitivity, specificity, PPV (positive predictive value), and NPV (negative predictive value) of mNGS in CSF for TBM were 84.44%(38/45, 69.94%-93.01%), 100%(6/6, 51.68%-100%), 100%(40/40, 88.57%-100%) and 46.15%(6/13, 20.40%-73.88%). The diagnostic sensitivity of mNGS(84.4%)was significantly higher than that of AFB (0%, P = 0.000), MGIT960 culture(22.2%, P = 0.000), MTB PCR(24.4%, P = 0.000) and Xpert MTB/RIF(40%, P = 0.000). The ROC curve showed that CSF protein quantification and CSF cell count might be valuable in the prediction of NGS positive detection of MTB (Mycobacterium tuberculosis).

CONCLUSION

CSF mNGS had high sensitivity, specificity and PPV in the diagnosis of TBM. Patients with a significant increase in CSF cell number and protein quantification might have a higher likelihood of positive MTB detection of NGS.

Preclinical models to optimize treatment of tuberculous meningitis - A systematic review

Tuberculous meningitis (TBM) is the most devastating form of TB, resulting in death or neurological disability in up to 50% of patients affected. Treatment is similar to that of pulmonary TB, despite poor cerebrospinal fluid (CSF) penetration of the cornerstone anti-TB drug rifampicin. Considering TBM pathology, it is critical that optimal drug concentrations are reached in the meninges, brain and/or the surrounding CSF. These type of data are difficult to collect in TBM patients. This review aims to identify and describe a preclinical model representative for human TBM which can provide the indispensable data needed for future pharmacological characterization and prioritization of new TBM regimens in the clinical setting. We reviewed existing literature on treatment of TBM in preclinical models: only eight articles, all animal studies, could be identified. None of the animal models completely recapitulated human disease and in most of the animal studies key pharmacokinetic data were missing, making the comparison with human exposure and CNS distribution, and the study of pharmacokinetic-pharmacodynamic relationships impossible. Another 18 articles were identified using other bacteria to induce meningitis with treatment including anti-TB drugs (predominantly rifampicin, moxifloxacin and levofloxacin). Of these articles the pharmacokinetics, i.e. plasma exposure and CSF:plasma ratios, of TB drugs in meningitis could be evaluated. Exposures (except for levofloxacin) agreed with human exposures and also most CSF:plasma ratios agreed with ratios in humans. Considering the lack of an ideal preclinical pharmacological TBM model, we suggest a combination of 1. basic physicochemical drug data combined with 2. in vitro pharmacokinetic and efficacy data, 3. an animal model with adequate pharmacokinetic sampling, microdialysis or imaging of drug distribution, all as a base for 4. physiologically based pharmacokinetic (PBPK) modelling to predict response to TB drugs in treatment of TBM.

Role of Aspirin in Tuberculous Meningitis: A Systematic Review and Meta-analysis

Objectives

Aspirin is a drug that has been found to be useful in reducing the incidence of infarctions. This systemic is aimed at review evaluating the benefits of aspirin in the management of tuberculous meningitis.

Methods

A systematic literature search was performed using PubMed, Cochrane Central Register of Controlled Trials, and SCOPUS for articles published on or before September 22, 2018. The meta-register of controlled trials and bibliography was also searched. Randomized controlled trials wherein aspirin was used were included in the systematic review. The data was extracted using a predetermined format. The risk ratio (RR) for dichotomous data was calculated and a random-effects model was used to combine the data. Death and occurrence of new infarctions were considered as primary outcomes. The quality of evidence was assessed using the GRADE approach.

Results

Four trials including 546 patients were found eligible. The addition of aspirin to anti-tuberculosis drug regimens did not significantly reduce mortality [RR = 0.66 (0.42-1.02); low-quality evidence] but significantly reduced the risk of new infarctions [RR = 0.52 (0.29-0.92); moderate-quality evidence]. Aspirin did not differ from the placebo with regard to the adverse event outcome.

Conclusion

Aspirin reduces the risk of new infarctions in patients with tuberculous meningitis but does not affect mortality (moderate-to-low level of evidence).

Metagenomic Next-Generation Sequencing for Diagnosis of Infectious Encephalitis and Meningitis: A Large, Prospective Case Series of 213 Patients

Purpose: We assessed the performance of metagenomic next-generation sequencing (mNGS) in the diagnosis of infectious encephalitis and meningitis.

Methods: This was a prospective multicenter study. Cerebrospinal fluid samples from patients with viral encephalitis and/or meningitis, tuberculous meningitis, bacterial meningitis, fungal meningitis, and non-central nervous system (CNS) infections were subjected to mNGS.

Results: In total, 213 patients with infectious and non-infectious CNS diseases were finally enrolled from November 2016 to May 2019; the mNGS-positive detection rate of definite CNS infections was 57.0%. At a species-specific read number (SSRN) ≥2, mNGS performance in the diagnosis of definite viral encephalitis and/or meningitis was optimal (area under the curve [AUC] = 0.659, 95% confidence interval [CI] = 0.566–0.751); the positivity rate was 42.6%. At a genus-specific read number ≥1, mNGS performance in the diagnosis of tuberculous meningitis (definite or probable) was optimal (AUC=0.619, 95% CI=0.516–0.721); the positivity rate was 27.3%. At SSRNs ≥5 or 10, the diagnostic performance was optimal for definite bacterial meningitis (AUC=0.846, 95% CI = 0.711–0.981); the sensitivity was 73.3%. The sensitivities of mNGS (at SSRN ≥2) in the diagnosis of cryptococcal meningitis and cerebral aspergillosis were 76.92 and 80%, respectively.

Conclusion: mNGS of cerebrospinal fluid effectively identifies pathogens causing infectious CNS diseases. mNGS should be used in conjunction with conventional microbiological testing.

Trial Registration: Chinese Clinical Trial Registry, ChiCTR1800020442.

Diagnostic Usefulness of Cytokine and Chemokine Levels in the Cerebrospinal Fluid of Patients with Suspected Tuberculous Meningitis

In this study, we investigated the diagnostic utility of the cytokine profile of the cerebrospinal fluid (CSF) and enzyme-linked immunospot (ELISPOT) assays of patients with suspected tuberculous meningitis (TBM). We prospectively enrolled adult patients with suspected TBM, and CSF specimens were analyzed for 18 cytokines/chemokines and soluble programmed death protein 1 (PD-1) and programmed death ligand 1 (PD-L1). Enzyme-linked immunospot assays were performed on mononuclear cells from the CSF (CSF-MCs) and peripheral blood (PBMCs). A total of 87 patients with meningitis, including 42 TBM-suspected patients and 45 non-TBM patients, were enrolled. Excluding the 32 patients with possible TBM, 10 patients with TBM and 45 patients with non-TBM were finally analyzed. Levels of adenosine deaminase (ADA), interleukin 12 subunit β (IL-12p40), IL-13, macrophage inflammatory protein α (MIP-1α), and soluble PD-1 and PD-L1 in the CSF were significantly higher in the TBM group than in the non-TBM group (P < 0.05). The optimal cutoff values for the sensitivities and specificities of the test methods for diagnosing TBM with small samples of 10 cases of definite or probable TBM were as follows: ADA > 6.95 U/L, 70% and 81%; IL-12p40 > 52.04 pg/mL, 80% and 73%; IL-13 > 0.44 pg/mL, 90% and 47%; MIP-1α > 8.83 pg/mL, 80% and 62%; soluble PD-1 > 35.87 pg/mL, 80% and 63%; soluble PD-L1 > 24.19 pg/mL, 80% and 61%; CSF-MC ELISPOT > 13.5 spots/250,000 CSF-MC, 30% and 91%; and PBMC ELISPOT > 14 spots/250,000 PBMCs, 50% and 78%, respectively. Therefore, CSF IL-12p40, IL-13, MIP-1α, and soluble PD-1 and PD-L1 concentrations appear to be useful adjuncts for diagnosing TBM.

Xpert MTB/RIF Ultra versus Xpert MTB/RIF for the diagnosis of tuberculous meningitis: a prospective, randomised, diagnostic accuracy study

BACKGROUND

Xpert MTB/RIF Ultra (Xpert Ultra) might have higher sensitivity than its predecessor, Xpert MTB/RIF (Xpert), but its role in tuberculous meningitis diagnosis is uncertain. We aimed to compare Xpert Ultra with Xpert for the diagnosis of tuberculous meningitis in HIV-uninfected and HIV-infected adults.

METHODS

In this prospective, randomised, diagnostic accuracy study, adults (≥16 years) with suspected tuberculous meningitis from a single centre in Vietnam were randomly assigned to cerebrospinal fluid testing by either Xpert Ultra or Xpert at baseline and, if treated for tuberculous meningitis, after 3-4 weeks of treatment. Test performance (sensitivity, specificity, and positive and negative predictive values) was calculated for Xpert Ultra and Xpert and compared against clinical and mycobacterial culture reference standards. Analyses were done for all patients and by HIV status.

FINDINGS

Between Oct 16, 2017, and Feb 10, 2019, 205 patients were randomly assigned to Xpert Ultra (n=103) or Xpert (n=102). The sensitivities of Xpert Ultra and Xpert for tuberculous meningitis diagnosis against a reference standard of definite, probable, and possible tuberculous meningitis were 47·2% (95% CI 34·4-60·3; 25 of 53 patients) for Xpert Ultra and 39·6% (27·6-53·1; 21 of 53) for Xpert (p=0·56); specificities were 100·0% (95% CI 92·0-100·0; 44 of 44) and 100·0% (92·6-100·0; 48 of 48), respectively. In HIV-negative patients, the sensitivity of Xpert Ultra was 38·9% (24·8-55·1; 14 of 36) versus 22·9% (12·1-39·0; eight of 35) by Xpert (p=0·23). In HIV co-infected patients, the sensitivities were 64·3% (38·8-83·7; nine of 14) for Xpert Ultra and 76·9% (49·7-91·8; ten of 13) for Xpert (p=0·77). Negative predictive values were 61·1% (49·6-71·5) for Xpert Ultra and 60·0% (49·0-70·0) for Xpert. Against a reference standard of mycobacterial culture, sensitivities were 90·9% (72·2-97·5; 20 of 22 patients) for Xpert Ultra and 81·8% (61·5-92·7; 18 of 22) for Xpert (p=0·66); specificities were 93·9% (85·4-97·6; 62 of 66) and 96·9% (89·5-91·2; 63 of 65), respectively. Six (22%) of 27 patients had a positive test by Xpert Ultra after 4 weeks of treatment versus two (9%) of 22 patients by Xpert.

INTERPRETATION

Xpert Ultra was not statistically superior to Xpert for the diagnosis of tuberculous meningitis in HIV-uninfected and HIV-infected adults. A negative Xpert Ultra or Xpert test does not rule out tuberculous meningitis. New diagnostic strategies are urgently required.

FUNDING

Wellcome Trust and the Foundation for Innovative New Diagnostics.

New-onset seizures in adults with tuberculous meningitis during long-term follow-up: Characteristics, functional outcomes and risk factors

OBJECTIVE

This study aimed to determine the characteristics and risk factors of adult new-onset seizure patients with tuberculous meningitis (TBM) during long-term follow-up.

METHODS

Patients with TBM who were seen between June 2012 and January 2018 were retrospectively reviewed and categorized into two groups based on the presence or absence of new-onset seizures. Seizure characteristics, functional outcomes and risk factors were assessed.

RESULTS

A total of 223 patients with TBM were enrolled, including 20.6% (46/223) with seizures. In all, 39.1% (18/46) of the patients with new-onset seizures and 14.1% (25/177) of the patients without seizures died (p < 0.001). Seizures were classified as single (n = 14/46, 30.4%), repetitive (n = 25/46, 54.3%), or status epilepticus (n = 7/46, 15.2%). We found that non-single seizures (repetitive seizures and status epilepticus) were associated with mortality (P = 0.002, P = 0.022), while single seizures were not (P = 0.834). The independent risk factors associated with non-single seizures were cortical involvement (p = 0.007) and epileptiform discharges (p = 0.001).

CONCLUSIONS

Non-single seizures were associated with poor functional outcomes and should be noted by the clinic. Cortical involvement and epileptiform discharges are independent risk factors for non-single seizures.

Decision-making in the diagnosis of tuberculous meningitis

Tuberculous meningitis (TBM) is the most devastating form of tuberculosis (TB) but diagnosis is difficult and delays in initiating therapy increase mortality. All currently available tests are imperfect; culture of Mycobacterium tuberculosis from the cerebrospinal fluid (CSF) is considered the most accurate test but is often negative, even when disease is present, and takes too long to be useful for immediate decision making. Rapid tests that are frequently used are conventional Ziehl-Neelsen staining and nucleic acid amplification tests such as Xpert MTB/RIF and Xpert MTB/RIF Ultra. While positive results will often confirm the diagnosis, negative tests frequently provide insufficient evidence to withhold therapy. The conventional diagnostic approach is to determine the probability of TBM using experience and intuition, based on prevalence of TB, history, examination, analysis of basic blood and CSF parameters, imaging, and rapid test results. Treatment decisions may therefore be both variable and inaccurate, depend on the experience of the clinician, and requests for tests may be inappropriate. In this article we discuss the use of Bayes' theorem and the threshold model of decision making as ways to improve testing and treatment decisions in TBM. Bayes' theorem describes the process of converting the pre-test probability of disease to the post-test probability based on test results and the threshold model guides clinicians to make rational test and treatment decisions. We discuss the advantages and limitations of using these methods and suggest that new diagnostic strategies should ultimately be tested in randomised trials.

Tubercular meningitis in patients with systemic lupus erythematosus: clinical characteristics, risk factors, and outcomes of 10 patients

Tubercular meningitis (TBM) is a rare condition in patients with systemic lupus erythematosus (SLE). The aim of this study is to describe the clinical characteristics, possible risk factors, and outcomes of SLE patients with TBM. We systematically reviewed medical records from10 SLE patients with TBM admitted to our hospital from December 2008 to December 2018. A total of 100 cases in the same period were randomly selected as controls from SLE inpatients without infection. In patients with TBM, the mean age at presentation was 35.2 years (range 19.8-45.2); the mean duration of SLE was 34.6 months (range 4-84 months). Patients with TBM had significantly longer SLE duration, higher ESR and CRP level, and lower CD4+ cell counts and albumin level than those without infections (p < 0.05 for all). There were no differences in prednisone dose at the time of symptom onset or cumulative dose over the preceding year between the two groups. Logistic regression analysis showed that patients with a lower CD4+ cell count were more likely to have TBM compared with controls (OR = 3.67, p = 0.020). TBM should be considered when SLE patients have central nervous system (CNS) symptoms with a longer duration, higher ESR and CRP level, and lower CD4+ cell counts and albumin level, even if the patients are receiving a low prednisone dose.Key Points• Patients with TBM have significantly longer SLE duration and lower CD4+ cell counts and albumin level than those without infections; lower CD4+ cell count was an independent risk factor to have TBM in patients with SLE.

Intensified adjunctive corticosteroid therapy for CNS tuberculomas

INTRODUCTION

Central nervous system (CNS) tuberculomas are a challenging manifestation of extrapulmonary tuberculosis often leading to neurological complications and post-treatment sequelae. The role of adjunctive corticosteroid treatment is not fully understood. Most guidelines on management of tuberculosis do not distinguish between tuberculous meningitis and CNS tuberculomas in terms of corticosteroid therapy.

METHODS

We describe five patients with CNS tuberculomas who required intensified dexamethasone treatment for several months, in two cases up to 18 months.

RESULTS

These patients were initially treated with the standard four-drug tuberculosis regimen and adjuvant dexamethasone. Neurological symptoms improved rapidly. However, multiple attempts to reduce or discontinue corticosteroids according to guideline recommendations led to clinical deterioration with generalized seizures or new CNS lesions. Thus, duration of adjunctive corticosteroid therapy was extended eventually leading to clinical cure and resolution of lesions.

CONCLUSION

In contrast to tuberculous meningitis, the treatment for CNS tuberculomas appears to require a prolonged administration of corticosteroids. These findings need to be verified in controlled clinical studies.

Effectiveness of Intravenous Isoniazid and Ethambutol Administration in Patients with Tuberculosis Meningoencephalitis and HIV Infection

Background

The aim of this study was to investigate the effectiveness of intravenous isoniazid (H) and ethambutol (E) administered in patients with new sputum positive drug-susceptible pulmonary tuberculosis (TB) with tuberculous meningoencephalitis (TM) and human immunodeficiency virus (HIV) co-infection in the intensive phase of treatment.

Methods

Fifty-four patients with TB/TM and HIV co-infection were enrolled for this study. Group 1 comprised of 23 patients treated with E and H intravenously, while rifampicin and pyrazinamide were prescribed orally. Group 2 consisted of 31 patients treated with the first-line anti-TB drugs orally. The concentrations of H and E in blood serum were detected using a chromatographic method.

Results

A significant improvement in the clinical symptoms and X-ray signs in patients treated intravenously with H and E was observed and compared to group 2. The sputum Mycobacterium tuberculosis positivity was observed during the second month of the treatment in 25.0% of patients from group 1 and 76.1% of the patients from the control group (p=0.003). In addition, nine patients (39.1%) died up to 6 months when H and E were prescribed intravenously compared with 22 (70.9%) in group 2 (p=0.023).

Conclusion

In TB/TM with HIV, the intravenous H and E treatment was more effective than oral H and E treatment at 2 months of intensive treatment in sputum conversion as well as in clinical improvement, accompanied by significantly higher mean serum concentrations. In addition, the mortality rate was lower in intravenous H and E treatment compared to oral treatment.

Mycobacterium tuberculosis and Pseudoramibacter alactolyticus coinfection in brain after dental extraction: A case report

INTRODUCTION

More than 1200 different types of microbes were found in the human mouth, only some of these microorganisms were associated with intracranial bacterial infection. However, there are limited data available about the Pseudoramibacter alactolyticus (P alactolyticus) or Mycobacterium tuberculosis (MTB) intracranial infections oral origin.

PATIENT CONCERNS

Here, we reported a rarely case with P alactolyticus and MTB coinfection in central nervous after dental extraction. The 44-year-old man presented with progressive headache over the last 2 weeks and a sustained fever >39°C, with a dental extraction performed 2 days before the onset of headache.

DIAGNOSIS

P alactolyticus and MTB were confirmed by real-time polymerase chain reaction targeting the16S ribosomal RNA gene. The presence of MTB was also demonstrated by positive acid-fast staining of the purulent discharge.

INTERVENTIONS

The patient was treated by metronidazole and anti-TB treatment OUTCOMES:: The patient fully recovered without sequela.

CONCLUSION

In conclusion there should be awareness of the possibility of P alactolyticus or MTB intracranial infections following tooth extraction.

Knowledge gaps and research priorities in tuberculous meningitis

Tuberculous meningitis (TBM) is the most severe and disabling form of tuberculosis (TB), accounting for around 1-5% of the global TB caseload, with mortality of approximately 20% in children and up to 60% in persons co-infected with human immunodeficiency virus even in those treated. Relatively few centres of excellence in TBM research exist and the field would therefore benefit from greater co-ordination, advocacy, collaboration and early data sharing. To this end, in 2009, 2015 and 2019 we convened the TBM International Research Consortium, bringing together approximately 50 researchers from five continents. The most recent meeting took place on 1 st and 2 nd March 2019 in Lucknow, India. During the meeting, researchers and clinicians presented updates in their areas of expertise, and additionally presented on the knowledge gaps and research priorities in that field. Discussion during the meeting was followed by the development, by a core writing group, of a synthesis of knowledge gaps and research priorities within seven domains, namely epidemiology, pathogenesis, diagnosis, antimicrobial therapy, host-directed therapy, critical care and implementation science. These were circulated to the whole consortium for written input and feedback. Further cycles of discussion between the writing group took place to arrive at a consensus series of priorities. This article summarises the consensus reached by the consortium concerning the unmet needs and priorities for future research for this neglected and often fatal disease.

Treatment outcomes of tuberculous meningitis in adults: a systematic review and meta-analysis

Background

Tuberculous meningitis is the most devastating presentation of disease with Mycobacterium tuberculosis. We sought to evaluate treatment outcomes for adult patients with this disease.

Methods

The Ovid MEDLINE, EMBASE, Cochrane Library and Web of Science databases were searched to identify all relevant studies. We pooled appropriate data to estimate treatment outcomes at the end of treatment and follow-up.

Results

Among the articles identified, 22 met our inclusion criteria, with 2437 patients. In a pooled analysis, the risk of death was 24.7% (95%CI: 18.7–31.9). The risk of neurological sequelae among survivors was 50.9% (95%CI: 40.2–61.5). Patients diagnosed in stage III or human immunodeficiency virus (HIV) positive were significantly more likely to die (64.8, 53.4% respectively) during treatment. The frequency of cerebrospinal fluid (CSF) acid-fast-bacilli smear positivity was 10.0% (95% CI 5.5–17.6), 23.8% (15.2–35.3) for CSF culture positivity, and 22.3% (17.8–27.5) for CSF polymerase chain reaction positivity. We found that the headache, fever, vomiting, and abnormal chest radiograph were the most common symptoms and diagnostic findings among tuberculous meningitis patients.

Conclusions

Despite anti-tuberculosis treatment, adult tuberculous meningitis has very poor outcomes. The mortality rate of patients diagnosed in stage III or HIV co-infection increased significantly during treatment.

Recent Developments in Tuberculous Meningitis Pathogenesis and Diagnostics

The pathogenesis of Tuberculous meningitis (TBM) is poorly understood, but contemporary molecular biology technologies have allowed for recent improvements in our understanding of TBM. For instance, neutrophils appear to play a significant role in the immunopathogenesis of TBM, and either a paucity or an excess of inflammation can be detrimental in TBM. Further, severity of HIV-associated immunosuppression is an important determinant of inflammatory response; patients with the advanced immunosuppression (CD4+ T-cell count of <150 cells/μL) having higher CSF neutrophils, greater CSF cytokine concentrations and higher mortality than those with CD4+ T-cell counts > 150 cells/μL. Host genetics may also influence outcomes with LT4AH genotype predicting inflammatory phenotype, steroid responsiveness and survival in Vietnamese adults with TBM. Whist in Indonesia, CSF tryptophan level was a predictor of survival, suggesting tryptophan metabolism may be important in TBM pathogenesis. These varying responses mean that we must consider whether a "one-size-fits-all" approach to anti-bacillary or immunomodulatory treatment in TBM is truly the best way forward. Of course, to allow for proper treatment, early and rapid diagnosis of TBM must occur. Diagnosis has always been a challenge but the field of TB diagnosis is evolving, with sensitivities of at least 70% now possible in less than two hours with GeneXpert MTB/Rif Ultra. In addition, advanced molecular techniques such as CRISPR-MTB and metagenomic next generation sequencing may hold promise for TBM diagnosis. Host-based biomarkers and signatures are being further evaluated in childhood and adult TBM as adjunctive biomarkers as even with improved molecular assays, cases are still missed. A better grasp of host and pathogen behaviour may lead to improved diagnostics, targeted immunotherapy, and possibly biomarker-based, patient-specific treatment regimens.

Structure-based Discovery of Narirutin as a Shikimate kinase Inhibitor with Anti-tubercular Potency

BACKGROUND

Shikimate pathway is essential for tubercular bacillus but it is absent in mammals. Therefore, Shikimate kinase and other enzymes in the pathway are potential targets for the development of novel anti-tuberculosis drugs.

OBJECTIVE

In the present study, Shikimate kinase is selected as the target for in silico screening of phytochemicals with an aim to discover a novel herbal drug against Mycobacterium tuberculosis (Mtb).

METHODS

A structure-based drug discovery approach is undertaken for the execution of the objective. Virtual screening of phytochemical database NPACT against the target, Shikimate kinase (PDB ID 3BAF), is carried out followed by toxicity and drug-likeness filtration. Finally, a lead, narirutin was selected for in vitro anti-tubercular study.

RESULTS

Narirutin, present in citrus fruits, emerges as the lead. It is considered to be non-toxic with predicted high LD50 value, 12000 mg/kg body weight. The phytochemical is tested for its antitubercular activity in vitro. It has MIC99 62.5 μg/mL against the MtbH37Rv strain.

CONCLUSION

This is the first-ever report to show anti-tuberculosis potency of narirutin.