Distinctive antibody responses to Mycobacterium tuberculosis in pulmonary and brain infection.

Mycobacterium tuberculosis (Mtb), the causative agent of tuberculosis (TB), remains a global health burden. While Mtb is primarily a respiratory pathogen, it can spread to other organs, including the brain and meninges, causing TB meningitis (TBM). However, little is known about the immunological mechanisms that leads to differential disease across organs. Attention has focused on differences in T cell responses in the control of Mtb in the lungs, but emerging data point to a role for antibodies, as both biomarkers of disease control and as antimicrobial molecules. Given an increasing appreciation for compartmentalized antibody responses across the blood brain barrier, here we characterized the antibody profiles across the blood and brain compartments during TBM, and determined whether Mtb-specific humoral immune responses differed between Mtb infection of the lung (pulmonary TB) and TBM. Using a high throughput systems serology approach, we deeply profiled the antibody responses against 10 different Mtb antigens, including lipoarabinomannan (LAM) and purified protein derivative (PPD), in HIV-negative adults with pulmonary TB (n=10) vs TBM (n=60). Antibody studies included analysis of immunoglobulin isotypes (IgG, IgM, IgA) and subclass levels (IgG1-4), the capacity of Mtb-specific antibodies to bind to Fc receptors or C1q, and to activate innate immune effectors functions (complement and NK cells activation, monocyte or neutrophil phagocytosis). Machine learning methods were applied to characterize serum and CSF responses in TBM, identify prognostic factors associated with disease severity, and define the key antibody features that distinguish TBM from pulmonary TB. In individuals with TBM, we identified CSF-specific antibody profiles that marked a unique and compartmentalized humoral response against Mtb, characterized by an enrichment of Mtb-specific antibodies able to robustly activate complement and drive phagocytosis by monocytes and neutrophils, all of which were associated with milder TBM severity at presentation. Moreover, individuals with TBM exhibited Mtb-specific antibodies in the serum with an increased capacity to activate phagocytosis by monocytes, compared to individuals with pulmonary TB, despite having lower IgG titers and Fcγ receptors (FcγR)-binding capacity. Collectively, these data point to functionally divergent humoral responses depending on the site of infection (i.e. lungs vs brain), and demonstrate a highly compartmentalized Mtb-specific antibody response within the CSF during TBM. Moreover, our results suggest that phagocytosis- and complement-mediating antibodies may promote attenuated neuropathology and milder TBM disease.

Cerebrospinal Fluid Bacillary Load by Xpert MTB/RIF Ultra Polymerase Chain Reaction Cycle Threshold Value Predicts 2-Week Mortality in Human Immunodeficiency Virus-Associated Tuberculous Meningitis.

BACKGROUND: The World Health Organization recommends GeneXpert MTB/RIF Ultra (Xpert Ultra), a fully automated polymerase chain reaction (PCR) assay, as the initial tuberculous meningitis (TBM) diagnostic test. The assay's PCR cycle threshold (Ct) values represent the number of PCR cycles required for probe signal to be detected (low Ct value = high bacillary load) and may approximate tuberculosis (TB) bacillary load. We measured the relationship between cerebrospinal fluid (CSF) TB bacillary load with mortality. METHODS: We prospectively enrolled 102 human immunodeficiency virus (HIV)-positive Ugandans with probable or definite TBM from April 2015 to August 2019. Xpert Ultra Ct tertiles and semi-quantitative categories were separately analyzed as predictors of 2-week mortality. We investigated associations between Ct and baseline clinical and CSF parameters. RESULTS: Subjects with Ct values in the low tertile (ie, high bacillary load) had 57% 2-week mortality-worse than the intermediate (17%) and high (25%) Ct tertiles and Xpert Ultra-negative (30%) probable TBM cases (P = .01). In contrast, the reported semi-quantitative Xpert Ultra categorization was less precise; with the medium to low category trending toward worse 2-week survival (42%) compared with very low (28%), trace (26%), and negative (30%) categories (P = .48). Ct tertile was significantly associated with baseline CSF lactate (P = .03). CONCLUSIONS: High CSF TB bacillary load, as measured by Xpert Ultra Ct tertile, is associated with an almost 2-fold higher 2-week mortality in HIV-associated TBM and is a better predictor than the reported Xpert Ultra semi-quantitative category. Xpert Ultra Ct values could identify TBM patients at increased risk of death who may benefit from enhanced supportive care.

Tuberculosis treatment in children: The changing landscape.

Traditionally children have been treated for tuberculosis (TB) based on data extrapolated from adults. However, we know that children present unique challenges that deserve special focus. New data on optimal drug selection and dosing are emerging with the inclusion of children in clinical trials and ongoing research on age-related pharmacokinetics and pharmacodynamics. We discuss the changing treatment landscape for drug-susceptible and drug-resistant paediatric tuberculosis in both the most common (intrathoracic) and most severe (central nervous system) forms of disease, and address the current knowledge gaps for improving patient outcomes.

Dancing Out of Step: A Case of Tuberculous Meningitis Presenting as Childhood Chorea.

Background: Acute to subacute pediatric movement disorders require prompt diagnosis to identify potentially treatable diseases. Case Report: We present a 6-year-old male with a three-week history of generalized chorea transitioning to predominantly right-sided hemichorea and then to left hemiplegia. Discussion: We review the mechanisms in tuberculous meningitis underlying his movement abnormalities.

The Role of Oxidative Stress in TB Meningitis and Therapeutic Options.

Meningitis is an inflammatory condition affecting the meninges surrounding the brain and spinal cord. Meningitis can be triggered by various factors, including infectious agents like viruses and bacteria and non-infectious contributors such as cancer or head injuries. The impact of meningitis on the central nervous system involves disruptions in the blood-brain barrier, cellular infiltrations, and structural alterations. The clinical features that differentiate between tuberculous meningitis (TBM) and non-tuberculous meningitis (NTM) are discussed in this review and aid in accurate diagnosis. The intricate interplay of reactive oxygen species, ferroptosis, and reactive nitrogen species within the central nervous system reveals a promising field of research for innovative therapeutic strategies tailored to TBM. This review highlights the alternative treatments targeting oxidative stress-induced TBM and ferroptosis, providing potential avenues for intervention in the pathogenesis of this complex condition.

Validation of a quantitative liquid chromatography tandem mass spectrometry assay for linezolid in cerebrospinal fluid and its application to patients with HIV-associated TB-meningitis.

Tuberculous meningitis treatment outcomes are poor and alternative regimens are under investigation. Reliable methods to measure drug concentrations in cerebrospinal fluid are required to evaluate distribution into the cerebrospinal fluid. A simple and quick method was developed and validated to analyse linezolid in human cerebrospinal fluid. Samples were prepared by protein precipitation followed by isocratic liquid chromatography and tandem mass spectrometry. The run time was 3.5 min. Accuracy and precision were assessed in three independent validation batches with a calibration range of 0.100-20.0 µg/mL. The method was used to analyse cerebrospinal fluid samples from patients with tuberculous meningitis enrolled in a clinical trial. Potentially infective patient samples could be decontaminated using Nanosep® nylon and Costar® nylon filter tubes under biosafety level 3 conditions before analysis. The filtration process did not significantly affect the quantification of linezolid. Linezolid concentration in cerebrospinal fluid obtained from tuberculous meningitis patients ranged from 0.197 µg/mL to 15.0 µg/mL. The ratio between average CSF and plasma linezolid concentrations varied with time, reaching a maximum of 0.9 at 6 h after dosing.

A Rare Diagnosis of Aseptic Hypertrophic Pachymeningitis: A Case of Mycobacterial Tuberculosis Origin.

Tubercular meningitis is a rare yet devastating type of extrapulmonary tuberculosis (TB) posing great diagnostic challenges due to the nonspecific clinical presentation of the patients. Here, we present a rare diagnosis of hypertrophic pachymeningitis due to Mycobacterium tuberculosis. A 36-year-old male presented with a history of headaches and giddiness for one month. Neurological examination revealed hypo-reflexive triceps and ankle reflexes. Routine blood tests and autoimmune workup were normal. Brain MRI with contrast revealed diffuse dural thickening, focal leptomeningeal enhancement in the right temporal sulci, and enhancement in both the frontal and parietal convexity and the falx cerebri and along the tentorium cerebelli. Cerebrospinal fluid (CSF) analysis revealed elevated proteins, suggestive of aseptic meningitis. Meningeal biopsy revealed a chronic ill-formed granulomatous inflammatory lesion with occasional acid-fast bacilli, consistent with tubercular pachymeningitis. The patient was administered intravenous (IV) methylprednisolone for five days, following which the symptoms subsided. He was advised tablet prednisolone on discharge, and immunomodulation with rituximab was recommended as outpatient treatment. Hypertrophic pachymeningitis is a rare diagnosis characterized by the inflammation and fibrosis of the dura matter due to a diverse etiology. Tubercular etiology must be considered when the routine laboratory tests are negative, and the diagnosis should be confirmed by meningeal biopsy. The treatment of the underlying cause and corticosteroids remain the mainstay management of hypertrophic pachymeningitis. Hence, mycobacterial tuberculosis should be considered as a possible differential diagnosis while evaluating hypertrophic pachymeningitis, especially when the routine laboratory tests and immunological workup are negative.

Outcome of tuberculous meningitis in children aged 9 months to 12 years at the end of intensive phase of treatment.

BACKGROUND: Tuberculous meningitis (TBM) is associated with high morbidity and mortality. Most of the literature focuses on outcomes at the end of therapy when it may be too late for intervention to improve the outcomes. So, the present study addresses outcomes by the end of intensive course of therapy. METHODS: It was a prospective cohort observational study that enrolled 80 patients with TBM between 9 months and 12 years of age. Participants were classified into Definite, Probable and Possible TBM using Marais criteria. Survival/Mortality was evaluated at the end of hospital stay. Demographic, clinical, cerebrospinal fluid and radiological parameters were evaluated for predictors of morbidity and mortality. Standardized tools were used to assess possible impairments in different domains at the end of intensive phase of treatment, namely Gross Motor Functional Classification System for motor functional ability, Pediatric-Mini Mental score examination (MMSE), Blantyre Coma Scale (BCS) score and Vineland Social Maturity Scale (VSMS) for cognitive outcome, Auditory Brainstem Evoked Responses for hearing outcome and using Teller's/Snellen's visual acuity charts to assess visual impairment. RESULTS: A high Mortality rate of 42.5% was seen in the enrolled patients. Out of the total 80 patients, 20% recovered completely while 36.25% survived with disability (morbidity). Motor, Hearing, Cognitive and Vision impairment was present in 33.3%, 4%, 33.3% and 48.9% of the survivors respectively. On multivariate regression, raised intracranial tension and stage III disease were significantly associated with mortality. Morbidity was significantly associated with Stage III disease on multivariate analysis. CONCLUSIONS: Despite advances in treatment, Tuberculous meningitis is associated with high burden of deaths and devastating neurological sequelae. Timely diagnosis and intervention of neurological impairments is needed to improve the outcome of TBM in survivors.

Cytomegalovirus pneumonia in a background of central nervous system tuberculosis.

A 32-year-old patient, who was on treatment for tuberculous meningitis complicated with venous sinus thrombosis, was referred to the medical unit as he developed new onset fever, cough and shortness of breath. He was in respiratory distress and needed intubation. Investigations revealed elevated liver enzymes, leukopenia, spherocytosis and lower lobe predominant consolidations and diffuse nodules in the high-resolution computed tomography. He was suspected to have cytomegalovirus (CMV) pneumonia with the above results, and further investigations revealed an extremely elevated CMV viral load. He was treated with ganciclovir followed by valganciclovir for a total of 42 days resulting in a complete recovery. Liver functions resolved with anti-viral treatment, and he was started on full anti-tuberculosis (TB) treatment. Further investigations did not reveal evidence of immunosuppression. Association of CMV and TB is explained genetically, although clinical association is rarely described. The presence of either infection should lead to higher degree of suspicion of the respective other condition in relevant clinical setting.

The Outcome of Surgical Intervention (Ventriculoperitoneal Shunt and Endoscopic Third Ventriculostomy) in Patients With Hydrocephalus Secondary to Tuberculous Meningitis: A Systematic Review.

The objective of this study is to analyze the outcome of the safety and efficiency of the surgical interventions (ventriculoperitoneal shunt [VPS] and endoscopic third ventriculostomy [ETV]) in patients with hydrocephalus due to tuberculous (TB) meningitis. A systematic literature search has been conducted using PubMed, Google Scholar, PMC, and ScienceDirect databases from 2001 to 2022 April. A total of 16 studies have been included, irrespective of their design. These studies include patients diagnosed with hydrocephalus secondary to TB meningitis (TBM) treated with VPS or ETV. A systematic review was conducted to determine the efficiency of surgical procedures based on the outcomes and complications associated with these procedures. A total of 2207 patients (aged one month to 68 years) have been included in this study, out of which 1723 underwent VPS and 484 underwent ETV. The overall success rate in the VPS group varied from 21.1% to 77.5%. The overall success rate in the ETV group ranged from 41.1% to 77%. The overall complications rate in the VPS group varied from 10% to 43.8%, and the complications rate in the ETV group varied from 3.8% to 22.5%. After ruling out the significant differences in the average percentages of outcomes and complications followed by VPS and ETV, ETV is suggested in patients with chronic phases of illness because the chances of ETV failure are high during the initial stage. The uncertainty of the ETV gradually decreases over time. To attain favourable long-term outcomes with ETV in patients with TBM hydrocephalus (TBMH), ETV should be performed after chemotherapy, anti-tubercular treatment, and steroids. In addition, ETV is considered beneficial over VP shunt as associated long-term complications are significantly less compared to VP shunt. In contrast, VP shunt is suggested as a modified Vellore grading which shows a more favourable outcome in patients with acute illness than ETV.

Improving Technology to Diagnose Tuberculous Meningitis: Are We There Yet?

Diagnosis of tuberculous meningitis (TBM) remains challenging due to a paucity of high-performance diagnostics. Even those that have reasonable sensitivity are not adequate to 'rule out' TBM. Therefore, a combination of clinical factors alongside microbiological, molecular, and radiological investigations are utilized, depending on availability. A low threshold for starting empiric therapy in the appropriate clinical scenario remains crucial for good outcomes in many cases. Herein, we review the current TBM diagnostics landscape with a focus on limitations frequently encountered, such as diagnostic test performance, cost, laboratory infrastructure, and clinical expertise. Though molecular technologies, particularly GeneXpert MTB/Rif Ultra, have been a step forward, diagnosis of TBM remains difficult. We also provide an overview of promising technologies, such as cerebrospinal fluid (CSF) lactate, a new lipoarabinomannan test (FujiLAM), metagenomic next-generation sequencing, and transcriptomics that may further improve our TBM diagnostic capacity and lead to better outcomes.

Addressing TB-related mortality in adults living with HIV: a review of the challenges and potential solutions.

Tuberculosis (TB) is the leading cause of death in people living with HIV (PLHIV) globally, causing 208,000 deaths in PLHIV in 2019. PLHIV have an 18-fold higher risk of TB, and HIV/TB mortality is highest in inpatient facilities, compared with primary care and community settings. Here we discuss challenges and potential mitigating solutions to address TB-related mortality in adults with HIV. Key factors that affect healthcare engagement are stigma, knowledge, and socioeconomic constraints, which are compounded in people with HIV/TB co-infection. Innovative approaches to improve healthcare engagement include optimizing HIV/TB care integration and interventions to reduce stigma. While early diagnosis of both HIV and TB can reduce mortality, barriers to early diagnosis of TB in PLHIV include difficulty producing sputum specimens, lower sensitivity of TB diagnostic tests in PLHIV, and higher rates of extra pulmonary TB. There is an urgent need to develop higher sensitivity biomarker-based tests that can be used for point-of-care diagnosis. Nonetheless, the implementation and scale-up of existing tests including molecular World Health Organization (WHO)-recommended diagnostic tests and urine lipoarabinomannan (LAM) should be optimized along with expanded TB screening with tools such as C-reactive protein and digital chest radiography. Decreased survival of PLHIV with TB disease is more likely with late HIV diagnosis and delayed start of antiretroviral (ART) treatment. The WHO now recommends starting ART within 2 weeks of initiating TB treatment in the majority of PLHIV, aside from those with TB meningitis. Dedicated TB treatment trials focused on PLHIV are needed, including interventions to improve TB meningitis outcomes given its high mortality, such as the use of intensified regimens using high-dose rifampin, new and repurposed drugs such as linezolid, and immunomodulatory therapy. Ultimately holistic, high-quality, person-centered care is needed for PLHIV with TB throughout the cascade of care, which should address biomedical, socioeconomic, and psychological barriers.

Management of syringomyelia associated with tuberculous meningitis: A case report and systematic review of the literature.

Determinants of tuberculosis (TB) syringomyelia, its management options and outcomes are still under investigation. The aim of this study is to present a case of TB syringomyelia with markedly improved symptoms status-post surgery and to understand the clinical characteristics and outcomes of 33 TB syringomyelia cases reported in the literature. Specifically, we examined the differences between patients who were managed medically and those who underwent surgical intervention. Inclusion criteria for the cases were (1) syringomyelia caused by TB infection rather than co-occurrence of these conditions, (2) management protocol described, and (3) post-treatment outcome described. The median age was 30 years (interquartile range (IQR): 23-40) with 55% males. The median time between TB onset to syringomyelia diagnosis was 2 years. Nineteen patients were surgically treated, 11 were medically treated, and 3 received no treatment. Twenty-one patients showed improvement in at least one prior symptom, but no patient experienced a full recovery. Those that underwent surgical intervention were more likely to have TB meningitis (95% vs. 64%, p < 0.05) upon initial TB presentation and have a greater interval between TB onset and syringomyelia presentation (median of 2.6 vs. 0.33 years, ns). A greater proportion of the surgically managed patients experienced improvement in any symptom (74% vs. 45%, ns). Future case-controlled studies with larger sample sizes are required to validate and further understand the outcomes of surgically-managed TB syringomyelia.

Comparison of patterns of infarction in TB and cryptococcal meningitis.

BACKGROUND: To compare the frequency and patterns of stroke, the specificity of tubercular zone (TBZ) infarction and its effect on outcomes in TB (TBM) and cryptococcal meningitis (CM). METHODS: This retrospective study was conducted at two tertiary centres in India from May 2018 to July 2020. Sixty-one patients with TBM and 22 with CM were included. The primary outcome was the proportions of TBM and CM patients with infarction. Secondary outcomes included the anatomical locations of infarction and in-hospital mortality. RESULTS: Infarction was noted in 52.5% of patients with TBM and in 54.5% of those with CM (p=0.87), with caudate head infarcts in 9.4% vs 41.7% (p=0.01), cerebellar in 9.4% vs 33.3% (p=0.05), thalamic in 25% vs 0% and lobar in 28.1% vs 0%, respectively. In TBM, the infarcts were located in the TBZ in 3 (9.4%), in the ischaemic zone in 23 (71.9%), while 6 (18.8%) patients showed infarcts in both, while in CM, the infarcts were in 0 (0%), 6 (50%) and 6 (50%) patients, respectively. Infarcts were not associated with in-hospital mortality, either in TBM or CM. CONCLUSION: Caudate head and cerebellar infarction was more common in CM, while thalamic and lobar infarcts were more frequent in TBM. TBZ infarcts were not specific to TBM.

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.

The role of optic nerve sheath diameter ultrasound in brain infection.

Brain infections cause significant morbidity and mortality worldwide, especially in resource-limited settings with high HIV co-infection rates. Raised intracranial pressure [ICP] may complicate brain infection and worsen neurological injury, yet invasive ICP monitoring is often unavailable. Optic nerve sheath diameter [ONSD] ultrasound may allow detection of raised ICP at the bedside; however, pathology in brain infection is different to traumatic brain injury, in which most studies have been performed. The use of ONSD ultrasound has been described in tuberculous meningitis, cryptococcal meningitis and cerebral malaria; however correlation with invasive ICP measurement has not been performed. Normal optic nerve sheath values are not yet established for most populations, and thresholds for clinical intervention cannot be assumed to match those used in non-infective brain pathology. ONSD ultrasound may be suitable for use in resource-limited settings by clinicians with limited ultrasound training. Standardisation of scanning technique, consensus on normal ONSD values, and action on abnormal results, are areas for future research. This scoping review examines the role of ONSD ultrasound in brain infection. We discuss pathophysiology, and describe the rationale, practicalities, and challenges of utilising ONSD ultrasound for brain infection monitoring and management. We discuss the existing evidence base for this technique, and identify knowledge gaps and future research priorities.

An improved protocol to establish experimental tuberculous meningitis in the rabbit.

Tuberculous meningitis (TBM), caused by Mycobacterium tuberculosis (Mtb), is the deadliest form of tuberculosis in humans, particularly in children and the geriatric population. However, the host-pathogen interactions underlying TBM is not well understood. Rabbits are a valuable model system to study TB in humans. The rabbit model of TB recapitulates several pathophysiological characteristics, including heterogeneity, architecture, and development of granulomas at the site of infection as observed in Mtb-infected human organs. Previously, our group has established a rabbit model of TBM that has been used to understand the host immune response to Mtb infection and to evaluate novel intervention therapies for TBM. In this model, rabbits infected intracisternally with Mtb showed histopathologic manifestations in the brain and meninges that are hallmarks of TBM in humans, including inflammatory cell accumulation and thickening of the leptomeninges. However, in this model, a helmet made of dental acrylic was attached to rabbit's skull with screws under anesthesia. At 24 h post-procedure, the animals were injected intracisternally with Mtb using a spinal needle. The rabbits were necropsied at various experimental time points up to 2 weeks post-infection. Although this method has been successful in establishing TBM, placement of the dental acrylic helmet on rabbit skull with screws that stays until the experimental endpoint poses stress to the animals and increases the chances of secondary infection. To alleviate these issues, we have developed an improved protocol, in which sedated rabbits are placed on specialised stereotaxic equipment and injected with Mtb intracisternally. This method is less cumbersome, faster, and more efficient in delivering the bacteria. Besides, the animals are not stressed by this method, compared to the previous one.

Mortality from HIV-associated meningitis in sub-Saharan Africa: a systematic review and meta-analysis.

INTRODUCTION: HIV-associated cryptococcal, TB and pneumococcal meningitis are the leading causes of adult meningitis in sub-Saharan Africa (SSA). We performed a systematic review and meta-analysis with the primary aim of estimating mortality from major causes of adult meningitis in routine care settings, and to contrast this with outcomes from clinical trial settings. METHODS: We searched PubMed, EMBASE and the Cochrane Library for published clinical trials (defined as randomized-controlled trials (RCTs) or investigator-managed prospective cohorts) and observational studies that evaluated outcomes of adult meningitis in SSA from 1 January 1990 through 15 September 2019. We performed random effects modelling to estimate pooled mortality, both in clinical trial and routine care settings. Outcomes were stratified as short-term (in-hospital or two weeks), medium-term (up to 10 weeks) and long-term (up to six months). RESULTS AND DISCUSSION: Seventy-nine studies met inclusion criteria. In routine care settings, pooled short-term mortality from cryptococcal meningitis was 44% (95% confidence interval (95% CI):39% to 49%, 40 studies), which did not differ between amphotericin (either alone or with fluconazole) and fluconazole-based induction regimens, and was twofold higher than pooled mortality in clinical trials using amphotericin based treatment (21% (95% CI:17% to 25%), 17 studies). Pooled short-term mortality of TB meningitis was 46% (95% CI: 33% to 59%, 11 studies, all routine care). For pneumococcal meningitis, pooled short-term mortality was 54% in routine care settings (95% CI:44% to 64%, nine studies), with similar mortality reported in two included randomized-controlled trials. Few studies evaluated long-term outcomes. CONCLUSIONS: Mortality rates from HIV-associated meningitis in SSA are very high under routine care conditions. Better strategies are needed to reduce mortality from HIV-associated meningitis in the region.

Radiosynthesis and PET Bioimaging of 76Br-Bedaquiline in a Murine Model of Tuberculosis.

Bedaquiline is a promising drug against tuberculosis (TB), but limited data are available on its intralesional pharmacokinetics. Moreover, current techniques rely on invasive tissue resection, which is difficult in humans and generally limited even in animals. In this study, we developed a novel radiosynthesis for 76Br-bedaquiline and performed noninvasive, longitudinal whole-body positron emission tomography (PET) in live, Mycobacterium tuberculosis-infected mice over 48 h. After the intravenous injection, 76Br-bedaquiline distributed to all organs and selectively localized to adipose tissue and liver, with excellent penetration into infected lung lesions (86%) and measurable penetration into the brain parenchyma (15%). Ex vivo high resolution, two-dimensional autoradiography, and same section hematoxylin/eosin and immunofluorescence provided detailed intralesional drug biodistribution. PET bioimaging and high-resolution autoradiography are novel techniques that can provide detailed, multicompartment, and intralesional pharmacokinetics of new and existing TB drugs. These technologies can significantly advance efforts to optimize drug dosing.

Intensified antibiotic treatment of tuberculosis meningitis.

INTRODUCTION: Meningitis is the most severe manifestation of tuberculosis, resulting in death or disability in over 50% of those affected, with even higher morbidity and mortality among patients with HIV or drug resistance. Antimicrobial treatment of Tuberculous meningitis (TBM) is similar to treatment of pulmonary tuberculosis, although some drugs show poor central nervous system penetration. Therefore, intensification of antibiotic treatment may improve TBM treatment outcomes. Areas covered: In this review, we address three main areas: available data for old and new anti-tuberculous agents; intensified treatment in specific patient groups like HIV co-infection, drug-resistance, and children; and optimal research strategies. Expert commentary: There is good evidence from preclinical, clinical, and modeling studies to support the use of high-dose rifampicin in TBM, likely to be at least 30 mg/kg. Higher dose isoniazid could be beneficial, especially in rapid acetylators. The role of other first and second line drugs is unclear, but observational data suggest that linezolid, which has good brain penetration, may be beneficial. We advocate the use of molecular pharmacological approaches, physiologically based pharmacokinetic modeling and pharmacokinetic-pharmacodynamic studies to define optimal regimens to be tested in clinical trials. Exciting data from recent studies hold promise for improved regimens and better clinical outcomes in future.