The Use of Murine Infection Models to Investigate the Protective Role of TNF in Central Nervous System Tuberculosis.

Tuberculosis of the central nervous system (CNS-TB) is the most severe form of extra-pulmonary tuberculosis that is often associated with high mortality. Secretion of tumor necrosis factor (TNF) has important protective and immune modulatory functions for immune responses during CNS-TB. Therefore, by combining the approaches of aerosol and intracerebral infection in mice, this chapter describes the methods to investigate the contribution of TNF in protective immunity against CNS-TB infection.

Fatal central nervous system co-infection with SARS-CoV-2 and tuberculosis in a healthy child.

BACKGROUND: Central and peripheral nervous system symptoms and complications are being increasingly recognized among individuals with pandemic SARS-CoV-2 infections, but actual detection of the virus or its RNA in the central nervous system has rarely been sought or demonstrated. Severe or fatal illnesses are attributed to SARS-CoV-2, generally without attempting to evaluate for alternative causes or co-pathogens. CASE PRESENTATION: A five-year-old girl with fever and headache was diagnosed with acute SARS-CoV-2-associated meningoencephalitis based on the detection of its RNA on a nasopharyngeal swab, cerebrospinal fluid analysis, and magnetic resonance imaging findings. Serial serologic tests for SARS-CoV-2 IgG and IgA showed seroconversion, consistent with an acute infection. Mental status and brain imaging findings gradually worsened despite antiviral therapy and intravenous dexamethasone. Decompressive suboccipital craniectomy for brain herniation with cerebellar biopsy on day 30 of illness, shortly before death, revealed SARS-CoV-2 RNA in cerebellar tissue using the Centers for Disease Control and Prevention 2019-nCoV Real-Time Reverse Transcriptase-PCR Diagnostic Panel. On histopathology, necrotizing granulomas with numerous acid-fast bacilli were visualized, and Mycobacterium tuberculosis complex DNA was detected by PCR. Ventricular cerebrospinal fluid that day was negative for mycobacterial DNA. Tracheal aspirate samples for mycobacterial DNA and culture from days 22 and 27 of illness were negative by PCR but grew Mycobacterium tuberculosis after 8 weeks, long after the child's passing. She had no known exposures to tuberculosis and no chest radiographic findings to suggest it. All 6 family members had normal chest radiographs and negative interferon-γ release assay results. The source of her tuberculous infection was not identified, and further investigations by the local health department were not possible because of the State of Michigan-mandated lockdown for control of SARS-CoV-2 spread. CONCLUSION: The detection of SARS-CoV-2 RNA in cerebellar tissue and the demonstration of seroconversion in IgG and IgA assays was consistent with acute SARS-CoV-2 infection of the central nervous infection. However, the cause of death was brain herniation from her rapidly progressive central nervous system tuberculosis. SARS-CoV-2 may mask or worsen occult tuberculous infection with severe or fatal consequences.

Multi-spectral Pattern of Clinical Presentation and the Resultant Outcome in Central Nervous System Tuberculosis: A Single Center Study on the Ubiquitous Pathogen.

Central nervous system (CNS) tuberculosis (TB) is a great medical masquerader having a multi-spectral pattern of clinical presentation, thereby complicating early diagnosis and appropriate management. This review article describes clinical presentation of CNS TB in a group of 47 patients, who were managed in the Nobel Medical College and Teaching Hospital in Biratnagar, Nepal during the last 2 years. We evaluated demographic profile, mode of management, and clinical outcome in these patients. The findings were that intracranial TB was present in 27 (57.5%) patients and the spinal involvement was in 20 (42.5%) patients. The most frequent presentation of the former was TB meningitis with hydrocephalus (55.5%) and that of the latter was Pott's spine with abscess in 50% of cases. TB meningitis with hydrocephalus was the commonest cause of mortality (83.3%) among the patients. CNS TB should be considered in the differential diagnosis in patients presenting with equivocal neurological signs and symptoms, especially in TB endemic regions. It seems prudent to commence early antitubercular therapy for safeguarding such patients from poor neurological outcome as well as mortality it harbingers.

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.

Bacterial Genotyping of Central Nervous System Tuberculosis in South Africa: Heterogenic Mycobacterium tuberculosis Infection and Predominance of Lineage 4.

Tuberculous meningitis (TBM), the most severe extrapulmonary manifestation of tuberculosis, is caused by the pathogen Mycobacterium tuberculosis The M. tuberculosis complex includes seven lineages, all described to harbor a unique geographical dissemination pattern and clinical presentation. In this study, we set out to determine whether a certain M. tuberculosis lineage demonstrated tropism to cause TBM in patients from Cape Town, South Africa. DNA was extracted from formalin-fixed paraffin-embedded central nervous system (CNS) tissue from a unique neuropathological cohort of 83 TBM patients, collected between 1975 and 2012. M. tuberculosis lineages 1, 2, 3, and 4 were determined using an allele-specific PCR and Sanger sequencing. Of the 83 patient specimens tested, bacterial characterization could be performed on 46 specimens (55%). M. tuberculosis lineage 4 was present in 26 patient specimens (56%), and non-lineage 4 was identified in 10 cases (22%). Moreover, genomic heterogeneity was detected in the CNS specimens of 7 adults and 3 children. We could show that infection of the CNS is not restricted to a single M. tuberculosis lineage and that even young children with rapid progression of disease can harbor more than one M. tuberculosis lineage in the CNS.

Human tuberculosis brain promotes neuronal apoptosis but not in astrocytes with high expression of vascular endothelial growth factor.

The present study aimed to investigate the involvement of the angiogenic marker vascular endothelia growth factor (VEGF) and apoptotic markers of Bcl-2 and Bax in the neurons and astrocytes in the brain infected by Mycobacterium tuberculosis. The immunohistochemistry staining was performed to analyze the expression of the VEGF, Bcl-2 and Bax in the astrocytes and neurons. The expression of VEGF was high in neurons and astrocytes in both the infected brain and control tissues with no difference of angiogenic activity (p = 0.40). Higher Bcl-2 expression was seen in astrocytes of infected brain tissues compared to the control tissues (p = 0.004) promoted a higher anti-apoptotic activity in astrocytes. The neurons expressed strong Bax expression in the infected brain tissues compared to the control tissues (p < 0.001), which indicated more apoptosis in neurons. Thus, neuronal death and survival of infected astrocytes together with high expression of VEGF might be associated with formation of brain tuberculosis. In conclusion, neurons could be more vulnerable than astrocytes in human tuberculosis brain with high expression of VEGF.

Cerebral tuberculosis in a patient with systemic lupus erythematosus following cyclophosphamide treatment: a case report.

Central nervous system (CNS) tuberculosis (TB) is a rare but catastrophic event in patients with systemic lupus erythematosus (SLE). Here we report a case of cerebral TB in a patient with lupus myocarditis and nephritis, following cyclophosphamide immunosuppression. To our knowledge this is the first reported case of cerebral TB in SLE in a non-endemic country. A 31-year-old female with SLE and a history of regular travel to Kenya presented to our centre with clinical features of acute heart failure. She was diagnosed with severe lupus myocarditis, and a renal biopsy also confirmed lupus nephritis. Prior to admission, she had also had a cough, fever and weight loss and was under investigation for suspected TB infection. She was treated with ivabradine, beta-blockers and diuretics together with methylprednisolone and cyclophosphamide immunosuppression. Subsequent sputum cultures confirmed TB and she was commenced on triple therapy. Despite this, she developed confusion, dizziness, blurred vision and fluctuating consciousness. Magnetic resonance imaging (MRI) and lumbar puncture revealed CNS TB infection resulting in meningitis. This was later complicated by obstructive hydrocephalus due to TB abscesses. A ventriculoperitoneal (VP) shunt was inserted and TB medications were given intravenously (IV) with dexamethasone. Following a prolonged hospital admission, the patient eventually recovered and rituximab treatment was used to control her SLE. TB infection has been associated with SLE flares. It is likely in this case that TB exacerbated a lupus flare and subsequent immunosuppression resulted in mycobacterial dissemination to the CNS. Systemic and CNS features of TB and SLE are difficult to distinguish and their contemporaneous management represents a diagnostic and therapeutic challenge.

Nitric oxide in cerebrospinal fluid of central nervous system tuberculosis: correlations with culture, antibody response, and cell count.

BACKGROUND/AIM: The role of nitric oxide (NO) has been established in infection over the years. NO functions by inhibiting the growth of intracellular pathogens. The present study was undertaken to ascertain the role of NO in central nervous system (CNS) infection by Mycobacterium tuberculosis. MATERIALS AND METHODS: A total of 781 chronic meningitis cerebrospinal fluid (CSF) samples suspected of CNS tuberculosis (TB) were categorized based on M. tuberculosis culture positivity, anti-TB antibody response, and CSF cell count and were analyzed for NO. RESULTS: We found that NO levels were positive in 10.88% of the CSF samples. Positivity for NO was 18%, 11.67%, 13.68%, 9.32%, and 9.66% in the cases with mycobacterial culture positivity, anti-TB antibody positivity, high cell count, low cell count, and zero cell count, respectively. Among the above cell count categories, NO levels were noticed to be elevated in high cell count samples with mononuclear cell predominance. CONCLUSION: This study suggests that NO might play some role in the later stages of tuberculous meningitis. This is the first study to our knowledge in which NO was evaluated in CSF in relation to immune response and the presence of a pathogen with such a large number of subjects.

Evaluation of Xpert MTB/RIF for Detection of Mycobacterium tuberculosis in Cerebrospinal Fluid.

Studies investigating Xpert MTB/RIF diagnostic performance on cerebrospinal fluid (CSF) samples are lacking in resource-rich settings. Xpert MTB/RIF results for 740 CSF samples from 698 patients across England were retrospectively compared with the results of culture of the same and contemporary samples. The overall sensitivity was calculated at 55%.

Challenges and perspectives in the diagnosis of extrapulmonary tuberculosis.

Extrapulmonary tuberculosis (EPTB) accounts for a significant proportion of tuberculosis cases worldwide. Nevertheless, the diagnosis is often delayed or even missed due to insidious clinical presentation and poor performance of diagnostic tests. Culture, the classical gold standard for tuberculosis, suffers from increased technical and logistical constraints in EPTB cases. In this review the authors outline current diagnostic options for the main forms of EPTB. The authors also discuss the opportunities and challenges linked in particular to microbiological diagnostics and to the attempts to find a new gold standard test for EPTB. Finally, new biomarkers and tests currently under evaluation are hopefully on the way to introduce significant improvements in EPTB diagnosis, for which clinical suspicion will nevertheless be essential.

High mortality in adults hospitalized for active tuberculosis in a low HIV prevalence setting.

BACKGROUND: This study aims to evaluate the outcomes of adults hospitalized for tuberculosis in a higher-income region with low HIV prevalence. METHODS: A retrospective cohort study was conducted on all adults hospitalized for pulmonary and/or extrapulmonary tuberculosis in an acute-care hospital in Hong Kong during a two-year period. Microscopy and solid-medium culture were routinely performed. The diagnosis of tuberculosis was made by: (1) positive culture of M. tuberculosis, (2) positive M. tuberculosis PCR result, (3) histology findings of tuberculosis infection, and/or (4) typical clinico-radiological manifestations of tuberculosis which resolved after anti-TB treatment, in the absence of alternative diagnoses. Time to treatment ('early', started during initial admission; 'late', subsequent periods), reasons for delay, and short- and long-term survival were analyzed. RESULTS: Altogether 349 patients were studied [median(IQR) age 62(48-77) years; non-HIV immunocompromised conditions 36.7%; HIV/AIDS 2.0%]. 57.9%, 16.3%, and 25.8% had pulmonary, extrapulmonary, and pulmonary-extrapulmonary tuberculosis respectively. 58.2% was smear-negative; 0.6% multidrug-resistant. 43.4% developed hypoxemia. Crude 90-day and 1-year all-cause mortality was 13.8% and 24.1% respectively. 57.6% and 35.8% received 'early' and 'late' treatment respectively, latter mostly culture-guided [median(IQR) intervals, 5(3-9) vs. 43(25-61) days]. Diagnosis was unknown before death in 6.6%. Smear-negativity, malignancy, chronic lung diseases, and prior exposure to fluoroquinolones (adjusted-OR 10.6, 95%CI 1.3-85.2) delayed diagnosis of tuberculosis. Failure to receive 'early' treatment independently predicted higher mortality (Cox-model, adjusted-HR 1.8, 95%CI 1.1-3.0). CONCLUSIONS: Mortality of hospitalized tuberculosis patients is high. Newer approaches incorporating methods for rapid diagnosis and initiation of anti-tuberculous treatment are urgently required to improve outcomes.

Neurons are host cells for Mycobacterium tuberculosis.

Mycobacterium tuberculosis infection of the central nervous system is thought to be initiated once the bacilli have breached the blood brain barrier and are phagocytosed, primarily by microglial cells. In this study, the interactions of M. tuberculosis with neurons in vitro and in vivo were investigated. The data obtained demonstrate that neurons can act as host cells for M. tuberculosis. M. tuberculosis bacilli were internalized by murine neuronal cultured cells in a time-dependent manner after exposure, with superior uptake by HT22 cells compared to Neuro-2a cells (17.7% versus 9.8%). Internalization of M. tuberculosis bacilli by human SK-N-SH cultured neurons suggested the clinical relevance of the findings. Moreover, primary murine hippocampus-derived neuronal cultures could similarly internalize M. tuberculosis. Internalized M. tuberculosis bacilli represented a productive infection with retention of bacterial viability and replicative potential, increasing 2- to 4-fold within 48 h. M. tuberculosis bacillus infection of neurons was confirmed in vivo in the brains of C57BL/6 mice after intracerebral challenge. This study, therefore, demonstrates neurons as potential new target cells for M. tuberculosis within the central nervous system.

Tuberculosis.

Tuberculosis remains a serious health problem worldwide, particularly affecting the poorest in both high-income and developing countries. It was declared a global emergency by the World Health Organization in 1993. Central nervous system (CNS) tuberculosis is caused by mycobacteria belonging to the Mycobacterium tuberculosis complex, and is acquired through inhalation of aerosolized droplet nuclei. Meningitis represents the most frequent and severe form of CNS tuberculosis. Parenchymal CNS involvement can occur in the form of tuberculoma or, more rarely, abscess. Also, damage of the spinal cord, roots, and spine can occur in the form of spinal meningitis, radiculomyelitis, spondylitis, or spinal cord infarction. Diagnosis remains a challenge due to the slow growth of the organisms and the low yield of cerebrospinal fluid cultures, as well as the frequent absence of evidence of infection elsewhere. This results in frequent empirical therapy, based on a combination of four drugs (isoniazid, rifampicin, pyrazinamide and ethambutol) for 2 months, followed by 10 additional months with two drugs (isoniazid and rifampicin) to a total duration of 12 months. Shorter regimens have also been successful, but there have been few controlled trials in patients with extrapulmonary disease. Corticoid therapy seems to be associated with a reduced risk of death, and is usually indicated. Evidence of multidrug resistance requires variable combinations of first- and second-line drugs; fortunately, resistance does not seem to represent a serious threat for CNS tuberculosis at present, but still requires the utmost vigilance.

Tuberculous radiculomyelitis presenting in a toddler with lower extremity weakness and seizure.

Tuberculous radiculomyelitis is an uncommon but serious complication of tuberculosis that can lead to considerable morbidity and mortality. We present the case of a 21-month-old male Congolese refugee diagnosed with tuberculous radiculomyelitis who presented with gradual motor and speech regression, and likely an infection-related seizure 2 months before diagnosis.