Xpert MTB/RIF Ultra for the diagnosis of HIV-associated tuberculous meningitis: a prospective validation study

Disease spectrum and prognostic factors in patients treated for tuberculous meningitis in Shaanxi province, China

Background

Tuberculous meningitis (TBM) is the most severe form of tuberculosis (TB) and can be difficult to diagnose and treat. We aimed to describe the clinical presentation, diagnosis, disease spectrum, outcome, and prognostic factors of patients treated for TBM in China.

Methods

A multicenter retrospective study was conducted from 2009 to 2019 enrolling all presumptive TBM patients referred to Xijing tertiary Hospital from 27 referral centers in and around Shaanxi province, China. Patients with clinical features suggestive of TBM (abnormal CSF parameters) were included in the study if they had adequate baseline information to be classified as "confirmed," "probable," or "possible" TBM according to international consensus TBM criteria and remained in follow-up. Patients with a confirmed alternative diagnosis or severe immune compromise were excluded. Clinical presentation, central nervous system imaging, cerebrospinal fluid (CSF) results, TBM score, and outcome-assessed using the modified Barthel disability index-were recorded and compared.

Findings

A total of 341 presumptive TBM patients met selection criteria; 63 confirmed TBM (25 culture positive, 42 Xpert-MTB/RIF positive), 66 probable TBM, 163 possible TBM, and 49 "not TBM." Death was associated with BMRC grade III (OR = 5.172; 95%CI: 2.298-11.641), TBM score ≥ 15 (OR = 3.843; 95%CI: 1.372-10.761), age > 60 years (OR = 3.566; 95%CI: 1.022-12.442), and CSF neutrophil ratio ≥ 25% (OR = 2.298; 95%CI: 1.027-5.139). Among those with confirmed TBM, nearly one-third (17/63, 27.0%) had a TBM score < 12; these patients exhibited less classic meningitis symptoms and signs and had better outcomes compared with those with a TBM score ≥ 12. In this group, signs of disseminated/miliary TB (OR = 12.427; 95%CI: 1.138-135.758) and a higher TBM score (≥15, OR = 8.437; 95%CI: 1.328-53.585) were most strongly associated with death.

Conclusion

TBM patients who are older (>60 years) have higher TBM scores or CSF neutrophil ratios, have signs of disseminated/miliary TB, and are at greatest risk of death. In general, more effort needs to be done to improve early diagnosis and treatment outcome in TBM patients.

Advancements in Tuberculosis Diagnostics: A Comprehensive Review of the Critical Role and Future Prospects of Xpert MTB/RIF Ultra Technology

Tuberculosis remains a persistent global health challenge, demanding swift and accurate diagnostic methods for effective treatment. The emergence of the Xpert MTB/RIF Ultra system marks a significant milestone in combating tuberculosis, streamlining the identification of Mycobacterium tuberculosis, and advancing our pursuit of eradicating the disease. Delving into the therapeutic landscape of tuberculosis and rifampicin resistance, this scientific narrative review offers a comprehensive exploration. It begins by delving into the historical backdrop and the hurdles encountered with traditional tuberculosis diagnostics. From there, it traces the journey of the Xpert MTB/RIF technology, underscoring its molecular underpinnings. In this narrative review, the performance of the Xpert MTB/RIF Ultra system undergoes thorough scrutiny, encompassing investigations into sensitivity, specificity, and comparisons with alternative diagnostic methods. The spotlight shines on its clinical applications across diverse scenarios, from diagnosing pulmonary and extrapulmonary tuberculosis to its pivotal role in identifying rifampicin resistance. The study also evaluates its clinical efficacy in enhancing patient outcomes and supporting global tuberculosis control initiatives. However, the review does not shy away from discussing the challenges and limitations associated with the Xpert MTB/RIF Ultra system. It meticulously addresses concerns regarding cost, infrastructure requirements, and potential diagnostic inaccuracies. Offering a panoramic view, the review assesses the system's impact in resource-constrained settings and its potential to bolster tuberculosis elimination endeavors worldwide. Peering into the future, it explores ongoing research avenues and potential enhancements in Xpert MTB/RIF Ultra technology, envisioning a landscape of improved performance, broader applications, and emerging diagnostic innovations in the realm of tuberculosis diagnostics.

Xpert MTB/RIF Ultra for the rapid diagnosis of extrapulmonary tuberculosis in a clinical setting of high tuberculosis prevalence country and interpretation of 'trace' results

To evaluate the diagnostic performance of Xpert MTB/RIF Ultra (Ultra) for the diagnosis of extrapulmonary tuberculosis (EPTB) from different types of extrapulmonary specimens in comparison with culture and composite microbiological reference standard (CRS). A total of 240 specimens were prospectively collected from presumptive EPTB patients between July 2021-January 2022 and tested by Ultra, Xpert, culture and acid-fast bacilli (AFB) smear microscopy. Out of 240 specimens, 35.8 %, 20.8 %, 11.3 %, and 7.1 % were detected as Mycobacterium tuberculosis complex by Ultra, Xpert, culture and AFB microscopy, respectively. An additional 15.0 % cases were detected by Ultra compared to Xpert MTB/RIF (Xpert) assay. A total of 28 (11.7 %) cases were identified as 'trace' category by Ultra with indeterminate rifampicin resistance result; of which 36.4 % were clinically confirmed as EPTB. Compared to culture, the sensitivity and specificity of Ultra and Xpert were 100 % and 72.3 %; 92.6 % and 88.3 %, respectively. In comparison with CRS, these were respectively: 98.9 % and 100 %; 57.5 % and 100 %. For individual category of specimens, sensitivity of Ultra was 100 % with varying specificity. We found that Ultra was highly sensitive for the rapid diagnosis of EPTB and has extensive potential over current diagnostics in high TB burden countries, but 'trace' results should be interpreted with caution.

The diagnosis of central nervous system infections in resource-limited settings and the use of novel and molecular diagnostic platforms to improve diagnosis

INTRODUCTION

Central nervous system infections (CNSI) disproportionately affect individuals in low-resource settings where diagnosis is challenging; large proportions of patients never receive a confirmed microbiological diagnosis resulting in inadequate management and high mortality. The epidemiology of CNSI varies globally and conventional diagnostics deployed in resource-limited settings have significant limitations, with an urgent need for improved diagnostic strategies.

AREAS COVERED

This review describes molecular platforms and other novel diagnostics used in the diagnosis of CNSI that are applicable to resource-limited settings. An extensive literature search of Medline and PubMed was performed. The emphasis is on investigations targeting infections of relevance to resource-limited settings either due to variation in regional CNSI epidemiology or due to increased prevalence in patients with immunosuppression. This includes commercially available multiplex PCR platforms, mycobacterial PCR platforms, and rapid diagnostics tests. To offer a framework for the optimal implementation in clinical settings, existing evidence highlighting the advantages and limitations of available platforms is reviewed.

EXPERT OPINION

The implementation of molecular platforms and other novel diagnostics has the potential to transform CNSI diagnosis in resource-limited settings, with several examples of successful rollout of novel diagnostics such as Xpert MTB/RIF Ultra and cryptococcal antigen testing.

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

PURPOSE OF REVIEW

Tuberculous meningitis (TBM) is the most severe form of tuberculosis. Inadequate diagnostic testing and treatment regimens adapted from pulmonary tuberculosis without consideration of the unique nature of TBM are among the potential drivers. This review focuses on the progress being made in relation to both diagnosis and treatment of TBM, emphasizing promising future directions.

RECENT FINDINGS

The molecular assay GeneXpert MTB/Rif Ultra has improved sensitivity but has inadequate negative predictive value to "rule-out" TBM. Evaluations of tests focused on the host response and bacterial components are ongoing. Clinical trials are in progress to explore the roles of rifampin, fluoroquinolones, linezolid, and adjunctive aspirin. Though diagnosis has improved, novel modalities are being explored to improve the rapid diagnosis of TBM. Multiple ongoing clinical trials may change current therapies for TBM in the near future.

[A case of tuberculous meningitis diagnosed early by direct Loop-Mediated Isothermal Amplification (LAMP) method using centrifuged medium of cerebrospinal fluid culture]

Tuberculous meningitis (TBM) is a central nervous system infection with a high mortality rate and requires early diagnosis and treatment. Identification of Mycobacterium tuberculosis in the cerebrospinal fluid is of primary importance in the diagnosis of TBM, however, conventional methods have some disadvantages: Rapid results tests such as smear and regular PCR method do not have sufficient diagnostic sensitivity; Nested PCR, which is one of the most sensitive tests, is not available in all facilities; Culture tests require a long period of 4-8 weeks for results. Here we report a case of TBM, diagnosed 14 days earlier than culture test by direct Loop-Mediated Isothermal Amplification (LAMP) method using centrifuged medium of cerebrospinal fluid (day 18) culture. The method we used here is simple, widely available, and considered to be useful for early detection of TBM.

Comparative performance of microbiological methods for the detection of tuberculous meningitis pathogens in cerebrospinal fluid

The aim of this study was to comprehensively evaluate metagenomic next-generation sequencing (mNGS), Acid-fast bacillus stain (AFB), MGIT960 culture, polymerase-chain-reaction (PCR), and Xpert MTB/RIF in the diagnosis of tuberculous meningitis (TBM). A cohort of 280 patients who presented with suspected TBM (ie, headache or altered mental status with clinical signs of meningism) were analyzed. The sensitivities of the 5 assays for the diagnosis of TBM ranged from 10.0% to 70.0%. The AFB had the lowest sensitivity of 10.0% (0.5-45.9), while mNGS and PCR had the highest sensitivity, both at 70.0% (35.4-91.9). mNGS demonstrated a distinct advantage in identifying a wider array of pathogens, including viruses, in CSF samples. PCR was a cost-effective option with excellent sensitivity and specificity. However, no single method was statistically significantly better than any other in the diagnosis of TBM. New diagnostic techniques are urgently needed for the independent, rapid and accurate detection of Mycobacterium tuberculosis to guide the diagnosis of TBM.

A systematic review and meta-analysis of the diagnostic accuracy of metagenomic next-generation sequencing for diagnosing tuberculous meningitis

Objective

The utility of metagenomic next-generation sequencing (mNGS) in the diagnosis of tuberculous meningitis (TBM) remains uncertain. We performed a meta-analysis to comprehensively evaluate its diagnostic accuracy for the early diagnosis of TBM.

Methods

English (PubMed, Medline, Web of Science, Cochrane Library, and Embase) and Chinese (CNKI, Wanfang, and CBM) databases were searched for relevant studies assessing the diagnostic accuracy of mNGS for TBM. Review Manager was used to evaluate the quality of the included studies, and Stata was used to perform the statistical analysis.

Results

Of 495 relevant articles retrieved, eight studies involving 693 participants (348 with and 345 without TBM) met the inclusion criteria and were included in the meta-analysis. The pooled sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, diagnostic odds ratio, and area under the summary receiver-operating characteristic curve of mNGS for diagnosing TBM were 62% (95% confidence interval [CI]: 0.46-0.76), 99% (95% CI: 0.94-1.00), 139.08 (95% CI: 8.54-2266), 0.38 (95% CI: 0.25-0.58), 364.89 (95% CI: 18.39-7239), and 0.97 (95% CI: 0.95-0.98), respectively.

Conclusions

mNGS showed good specificity but moderate sensitivity; therefore, a more sensitive test should be developed to assist in the diagnosis of TBM.

Recent advances in microbiological and molecular biological detection techniques of tuberculous meningitis

Tuberculous meningitis (TBM) is the most common type of central nervous system tuberculosis (TB) and has the highest mortality and disability rate. Early diagnosis is key to improving the prognosis and survival rate of patients. However, laboratory diagnosis of TBM is often difficult due to its paucibacillary nature and sub optimal sensitivity of conventional microbiology and molecular tools which often fails to detect the pathogen. The gold standard for TBM diagnosis is the presence of MTB in the CSF. The recognised methods for the identification of MTB are acid-fast bacilli (AFB) detected under CSF smear microscopy, MTB cultured in CSF, and MTB detected by polymerase chain reaction (PCR). Currently, many studies consider that all diagnostic techniques for TBM are not perfect, and no single technique is considered simple, fast, cheap, and efficient. A definite diagnosis of TBM is still difficult in current clinical practice. In this review, we summarise the current state of microbiological and molecular biological diagnostics for TBM, the latest advances in research, and discuss the advantages of these techniques, as well as the issues and challenges faced in terms of diagnostic effectiveness, laboratory infrastructure, testing costs, and clinical expertise, for clinicians to select appropriate testing methods.

Tuberculosis revisted: classic imaging findings in childhood

Tuberculosis (TB) remains one of the major public health threats worldwide, despite improved diagnostic and therapeutic methods. Tuberculosis is one of the main causes of infectious disease in the chest and is associated with substantial morbidity and mortality in paediatric populations, particularly in low- and middle-income countries. Due to the difficulty in obtaining microbiological confirmation of pulmonary TB in children, diagnosis often relies on a combination of clinical and radiological findings. The early diagnosis of central nervous system TB is challenging with presumptive diagnosis heavily reliant on imaging. Brain infection can present as a diffuse exudative basal leptomeningitis or as localised disease (tuberculoma, abscess, cerebritis). Spinal TB may present as radiculomyelitis, spinal tuberculoma or abscess or epidural phlegmon. Musculoskeletal manifestation accounts for 10% of extrapulmonary presentations but is easily overlooked with its insidious clinical course and non-specific imaging findings. Common musculoskeletal manifestations of TB include spondylitis, arthritis and osteomyelitis, while tenosynovitis and bursitis are less common. Abdominal TB presents with a triad of pain, fever and weight loss. Abdominal TB may occur in various forms, as tuberculous lymphadenopathy or peritoneal, gastrointestinal or visceral TB. Chest radiographs should be performed, as approximately 15% to 25% of children with abdominal TB have concomitant pulmonary infection. Urogenital TB is rare in children. This article will review the classic radiological findings in childhood TB in each of the major systems in order of clinical prevalence, namely chest, central nervous system, spine, musculoskeletal, abdomen and genitourinary system.

Diagnosis of extrapulmonary tuberculosis by GeneXpert MTB/RIF Ultra assay

INTRODUCTION

Diagnosis of extrapulmonary tuberculosis (EPTB) is an arduous task owing to different anatomical locations, unusual clinical presentations, and sparse bacillary load in clinical specimens. Although GeneXpert® MTB/RIF is a windfall in TB diagnostics including EPTB, it yields low sensitivities but high specificities in many EPTB specimens. To further improve the sensitivity of GeneXpert®, GeneXpert® Ultra, a fully nested real-time PCR targeting IS6110, IS1081 and rpoB (Rv0664) has been endorsed by the WHO (2017), wherein melt curve analysis is utilized to detect rifampicin-resistance (RIF-R).

AREA COVERED

We described the assay chemistry/work design of Xpert Ultra and evaluated its performance in several EPTB types, that is, TB lymphadenitis, TB pleuritis, TB meningitis, and so on, against the microbiological reference standard or composite reference standard. Notably, Xpert Ultra exhibited better sensitivities than Xpert, but mostly at the compensation of specificity values. Moreover, Xpert Ultra exhibited low false-negative and false-positive RIF-R results, compared with Xpert. We also detailed other molecular tests, that is, Truenat MTBTM/TruPlus, commercial real-time PCR, line probe assay, and so on, for EPTB diagnosis.

EXPERT OPINION

A combination of clinical features, imaging, histopathological findings, and Xpert Ultra are adequate for definite EPTB diagnosis so as to initiate an early anti-tubercular therapy.

A systematic review and repeatability study on the use of deep learning for classifying and detecting tuberculosis bacilli in microscopic images

Tuberculosis (TB) is among the leading causes of death worldwide from a single infectious agent. This disease usually affects the lungs (pulmonary TB) and can be cured in most cases with a quick diagnosis and proper treatment. Microscopic sputum smear is widely used to diagnose and manage pulmonary TB. Despite being relatively fast and low cost, it can be exhausting because it depends on manually counting TB bacilli (Mycobacterium tuberculosis) in microscope images. In this context, different Deep Learning (DL) techniques are proposed in the literature to assist in performing smear microscopy. This article presents a systematic review based on the PRISMA procedure, which investigates which DL techniques can contribute to classifying TB bacilli in microscopic images of sputum smears using the Ziehl-Nielsen method. After an extensive search and a careful inclusion/exclusion procedure, 28 papers were selected from a total of 400 papers retrieved from nine databases. Based on these articles, the DL techniques are presented as possible solutions to improve smear microscopy. The main concepts necessary to understand how such techniques are proposed and used are also presented. In addition, replication work is also carried out, verifying reproducibility and comparing different works in the literature. In this review, we look at how DL techniques can be a partner to make sputum smear microscopy faster and more efficient. We also identify some gaps in the literature that can guide which issues can be addressed in other works to contribute to the practical use of these methods in laboratories.

Tuberculosis of the Spinal Cord

Tuberculosis involving the spinal cord is associated with high mortality and disabling long-term sequelae. Although tuberculous radiculomyelitis is the most frequent complication, pleomorphic clinical manifestations exist. Diagnosis can be challenging among patients with isolated spinal cord tuberculosis due to diverse clinical and radiological presentations. The principles of management of tuberculosis of the spinal cord are primarily derived from, and dependent upon, trials on tuberculous meningitis (TBM). Although facilitating mycobacterial killing and controlling host inflammatory response within the nervous system remain the primary objectives, several unique features require attention. The paradoxical worsening is more frequent, often with devastating outcomes. The role of anti-inflammatory agents such as steroids in adhesive tuberculous radiculomyelitis remains unclear. Surgical interventions may benefit a small proportion of patients with spinal cord tuberculosis. Currently, the evidence base in the management of spinal cord tuberculosis is limited to uncontrolled small-scale data. Despite the gargantuan burden of tuberculosis, particularly in lower and middle-income countries, large-scale cohesive data are surprisingly sparse. In this review, we highlight the varied clinical and radiological presentations, performance of various diagnostic modalities, summarize data on the efficacy of treatment options, and propose a way forward to improve outcomes in these patients.

Diagnostic performance of real time PCR for the detection of Mycobacterium tuberculosis in cerebrospinal fluid samples

PURPOSE

We aimed this study to standardize real time - polymerase chain reaction (RT-PCR) for the detection of Mycobacterium tuberculosis (Mtb) in cerebrospinal fluid (CSF) samples and compare its diagnostic performance with GeneXpert (Xpert), Mycobacteria Growth Indicator Tube (MGIT) and Multiplex PCR (MPCR) for tuberculous meningitis (TBM).

METHODOLOGY

A total of 217 CSF samples were obtained from patients with suspected TBM during the study period between January 2019 and December 2021. The optimal cycle threshold (CT) of RT-PCR was determined by comparing different gene targets of Mtb (IS6110, 16SrRNA, HSP65 and Ag85B). Sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) was determined for RT-PCR, Xpert, MGIT960 and MPCR. Diagnostic accuracy of these assays was compared by using clinical diagnosis as reference standard.

RESULTS

IS6110RT-PCR was found to be highly sensitive as compared to other gene targets. Sensitivities of IS6110RT-PCR, MPCR, Xpert and MGIT against a reference standard of definite, probable and possible TBM were 36.7%, 21.1%, 16.7% and 6.7%, respectively; specificities were 97.6%, 100%, 100% and 100%, respectively. Xpert, RT-PCR, MPCR and MGIT960 detected 6.91% (n = 15), 5.99% (n = 13), 5.99% (n = 13) and 2.76% (n = 6) of definite TBM, respectively. RT-PCR detected 6.45% (n = 14) and 2.76% (n = 6) of possible TBM and probable TBM, respectively and MPCR detected 1.38% (n = 3) of possible and probable TBM each.

CONCLUSION

IS6110RT-PCR is highly sensitive for primary screening of suspected TB cases, which may help clinicians to start appropriate patient's treatment with clinical suspicion of TBM.

Microbiological diagnosis and mortality of tuberculosis meningitis: Systematic review and meta-analysis

BACKGROUND

Tuberculosis (TB) which is caused by Mycobacterium tuberculosis poses a significant public health global treat. Tuberculosis meningitis (TBM) accounts for approximately 1% of all active TB cases. The diagnosis of Tuberculosis meningitis is notably difficult due to its rapid onset, nonspecific symptoms, and the difficulty of detecting Mycobacterium tuberculosis in cerebrospinal fluid (CSF). In 2019, 78,200 adults died of TB meningitis. This study aimed to assess the microbiological diagnosis TB meningitis using CSF and estimated the risk of death from TBM.

METHODS

Relevant electronic databases and gray literature sources were searched for studies that reported presumed TBM patients. The quality of included studies was assessed using the Joanna Briggs Institute Critical Appraisal tools designed for prevalence studies. Data were summarized using Microsoft excel ver 16. The proportion of culture confirmed TBM, prevalence of drug resistance and risk of death were calculated using the random-effect model. Stata version 16.0 was used perform the statistical analysis. Moreover, subgroup analysis was conducted.

RESULTS

After systematic searching and quality assessment, 31 studies were included in the final analysis. Ninety percent of the included studies were retrospective studies in design. The overall pooled estimates of CSF culture positive TBM was 29.72% (95% CI; 21.42-38.02). The pooled prevalence of MDR-TB among culture positive TBM cases was 5.19% (95% CI; 3.12-7.25). While, the proportion of INH mono-resistance was 9.37% (95% CI; 7.03-11.71). The pooled estimate of case fatality rate among confirmed TBM cases was 20.42% (95%CI; 14.81-26.03). Based on sub group analysis, the pooled case fatality rate among HIV positive and HIV negative TBM individuals was 53.39% (95%CI; 40.55-66.24) and 21.65% (95%CI;4.27-39.03) respectively.

CONCLUSION

Definite diagnosis of TBM still remains global treat. Microbiological confirmation of TBM is not always achievable. Early microbiological confirmation of TBM has great importance to reduce mortality. There was high rate of MDR-TB among confirmed TBM patients. All TB meningitis isolates should be cultured and drug susceptibility tested using standard techniques.

Bacterial meningitis in Africa

Bacterial meningitis differs globally, and the incidence and case fatality rates vary by region, country, pathogen, and age group; being a life-threatening disease with a high case fatality rate and long-term complications in low-income countries. Africa has the most significant prevalence of bacterial meningitis illness, and the outbreaks typically vary with the season and the geographic location, with a high incidence in the meningitis belt of the sub-Saharan area from Senegal to Ethiopia. Streptococcus pneumoniae (pneumococcus) and Neisseria meningitidis (meningococcus) are the main etiological agents of bacterial meningitis in adults and children above the age of one. Streptococcus agalactiae (group B Streptococcus), Escherichia coli, and Staphylococcus aureus are neonatal meningitis's most common causal agents. Despite efforts to vaccinate against the most common causes of bacterial neuro-infections, bacterial meningitis remains a significant cause of mortality and morbidity in Africa, with children below 5 years bearing the heaviest disease burden. The factors attributed to this continued high disease burden include poor infrastructure, continued war, instability, and difficulty in diagnosis of bacterial neuro-infections leading to delay in treatment and hence high morbidity. Despite having the highest disease burden, there is a paucity of African data on bacterial meningitis. In this article, we discuss the common etiologies of bacterial neuroinfectious diseases, diagnosis and the interplay between microorganisms and the immune system, and the value of neuroimmune changes in diagnostics and therapeutics.

Diagnostic and therapeutic approach to chronic meningitis in Brazil: a narrative review

BACKGROUND

Chronic meningitis (CM) is characterized by neurological symptoms associated with the evidence of cerebrospinal fluid pleocytosis lasting > 4 weeks. Studies on the management of CM in Brazil are scarce.

OBJECTIVE

To critically review the literature on CM and propose a rational approach in the Brazilian scenario.

METHODS

Narrative literature review discussing the epidemiology, clinical evaluation, basic and advanced diagnostic testing, and empirical and targeted therapy for the most relevant causes of CM. The present review was contextualized with the local experience of the authors. In addition, we propose an algorithm for the management of CM in Brazil.

RESULTS

In Brazil, tuberculosis and cryptococcosis are endemic and should always be considered in CM patients. In addition to these diseases, neurosyphilis and other endemic conditions should be included in the differential diagnosis, including neurocysticercosis, Baggio-Yoshinari syndrome, and endemic mycosis. After infectious etiologies, meningeal carcinomatosis and autoimmune diseases should be considered. Unbiased and targeted methods should be used based on availability and clinical and epidemiological data.

CONCLUSION

We propose a rational approach to CM in Brazil, considering the epidemiological scenario, systematizing the etiological investigation, and evaluating the timely use of empirical therapies.

Xpert MTB/RIF Ultra in the auxiliary diagnosis of tuberculosis among people living with human immunodeficiency virus

Clinical diagnosis of tuberculosis (TB) in people living with the human immunodeficiency virus (HIV) poses a challenge. The Xpert MTB/RIF Ultra (Ultra) has displayed greater sensitivity at diagnosing tuberculosis and rifampicin resistance compared to the Xpert MTB/RIF (Xpert). However, whether Ultra is able to facilitate an auxiliary diagnosis of TB in patients with an HIV-TB co-infection remains unclear. Accordingly, the current study evaluated the use of Ultra in patients with an HIV-TB co-infection by summarizing relevant studies. The sensitivity and specificity of Ultra and Xpert at diagnosing patients with an HIV-TB co-infection have been summarized and compared. The performance of Ultra in diagnosing extrapulmonary tuberculosis was also summarized. Although a large-cohort, multi-center study needs to be conducted to assess Ultra's ability to detect TB in AIDS patients in the future, the current evidence supports the use of Ultra for the assessment of patients with an HIV-TB co-infection.

Cerebrospinal fluid lactate as a predictive biomarker for tuberculous meningitis diagnosis

Objectives

The definitive diagnosis of tuberculous meningitis (TBM) is achieved by identifying Mycobacterium tuberculosis (MTb) in cerebrospinal fluid (CSF); however, diagnostic confirmation is difficult due to the inability of current tests for an effective diagnosis. Our objective was to retrospectively assess the characteristics of CSF lactate (CSF-LA) as an adjunct biomarker in the diagnosis of TBM.

Methods

608 CSF laboratory reports were assessed. Of these, 560 had clinically suspected TBM. These were classified as definite (n=36), probable (23), possible (278), or non-TBM (223) according to the international consensus TBM case definitions. An additional 48 CSF samples were negative controls with normal CSF.

Results

Against a reference standard of definite TBM, the cut-off value for CSF-LA was 4.0 mmol/L, the area under the ROC curve was 0.88 (95% CI, 0.82–0.94; p=0.0001), sensitivity was 69%, specificity 90%, negative predictive value 98%. These diagnostic parameters decreased when calculated against those of the other categories of TBM. CSF-LA exhibited high specificity, efficiency, negative predictive value, and clinical utility index in all the groups studied.

Conclusions

CSF-LA is a useful diagnostic marker to rule out TBM when associated with conventional microbiology tests, nucleic acid amplification assays, and clinical algorithms, particularly in endemic areas.

High cerebrospinal fluid lactate concentration at 48 h of hospital admission predicts poor outcomes in patients with tuberculous meningitis: A multicenter retrospective cohort study

Objective

This study aimed to analyze the cerebrospinal fluid (CSF) parameters affecting the outcomes of patients with tuberculous meningitis (TBM).

Methods

This is a multi-center, retrospective, cohort study involving 81 patients who were diagnosed with TBM and treated in Haihe Clinical College of Tianjin Medical University, Tianjin Medical University General Hospital, and General Hospital of Air Force PLA from January 2016 to December 2019. Baseline data, Glasgow Coma Scale (GCS) score, and clinical presentations of all patients were collected at admission. CSF samples were collected at 48 h, 1, 2, and 3 weeks after admission. CSF lactate, adenosine deaminase, chloride, protein, glucose levels and intracranial pressure were measured. After a follow-up of 16.14 ± 3.03 months, all patients were assessed using the modified Rankin Scale (mRS) and divided into good (mRS scores of 0–2 points) and poor outcome groups (mRS scores of 3–6 points). The differences in patients' baseline data, GCS score, clinical presentations, and levels of CSF parameters detected at 48 h, 1, 2, and 3 weeks after admission between two groups were compared. Statistically significant variables were added to the binary logistic regression model to identify the factors impacting the outcomes of patients with TBM. Receiver operating characteristic (ROC) curve was used to assess the predictive ability of the model.

Results

The CSF lactate level exhibited a decreasing trend within 3 weeks of admission in the two groups. For the within-group comparison, statistically significant differences in the lactate level was found in both groups between four different time points. A binary logistic regression model revealed that CSF lactate level at 48 h after admission, age, and GSC score on admission were independently associated with the outcomes of patients with TBM. ROC curve analysis showed that the area under the ROC curve (AUC) was 0.786 for the CSF lactate level (48 h), 0.814 for GCS score, and 0.764 for age.

Conclusion

High CSF lactate level at 48 h after admission is one of the important factors for poor outcomes in patients with TBM.

Capacity Building in Sub-Saharan Africa as Part of the INTENSE-TBM Project During the COVID-19 Pandemic

Tuberculous meningitis (TBM) is the most severe and disabling form of tuberculosis (TB), with at least 100,000 cases per year and a mortality rate of up to 50% in individuals co-infected with human immunodeficiency virus type 1 (HIV-1). To evaluate the efficacy and safety of an intensified anti-tubercular regimen and an anti-inflammatory treatment, the INTENSE-TBM project includes a phase III randomised clinical trial (TBM-RCT) in four countries in sub-Saharan Africa (SSA). Within this framework, we designed a comprehensive capacity-building work package ensuring all centres had, or would acquire, the ability to conduct the TBM-RCT and developing a network of skilled researchers, clinical centres and microbiology laboratories. Here, we describe these activities, identify strengths/challenges and share tools adaptable to other projects, particularly in low- and lower-middle income countries with heterogeneous settings and during the coronavirus disease 2019 (COVID-19) pandemic. Despite major challenges, TBM-RCT initiation was achieved in all sites, promoting enhanced local healthcare systems and encouraging further clinical research in SSA. In terms of certified trainings, the achievement levels were 95% (124/131) for good clinical practice, 91% (39/43) for good clinical laboratory practice and 91% (48/53) for infection prevention and control. Platform-based research, developed as part of capacity-building activities for specific projects, may be a valuable tool in fighting future infectious diseases and in developing high-level research in Africa.

The INTENSE-TBM project aimed to design a comprehensive work-package on capacity building, ensuring all centres would acquire the ability to conduct a phase III randomised clinical trial on TBM in sub-Saharan Africa, to reduce tuberculous meningitis mortality and morbidity in patients with/without HIV-1 co-infection. Therefore, the INTENSE-TBM project is an example of how an international clinical research consortium can provide opportunities to enhance local capacity building and promote centres without previous experience in clinical research. This article provides practical approaches for implementing effective capacity-building programmes. We highlight how to overcome limitations imposed by the COVID-19 pandemic to successfully complete clinics, laboratory set-ups and personnel training, so as to optimise resources and empower African institutions on a local level. At the same time, our experience shows how capacity-building programmes can deliver long-lasting impact that extends beyond the original aims of the project (e.g. HIV and TB), and support local health systems in fighting other infectious disease (e.g. COVID-19). Research projects in low- and lower-middle income countries with heterogeneous settings could stand to benefit the most.

Accuracy of Xpert MTB/RIF Ultra for the diagnosis of tuberculosis in adult patients: a retrospective cohort study

OBJECTIVES

The value of the "trace" result in Xpert Ultra for diagnosing active tuberculosis (TB) remains unclear. Our study evaluated the diagnostic accuracy of Xpert MTB/RIF Ultra (Xpert Ultra) (Cepheid, Sunnyvale, USA) over Xpert MTB/RIF (Xpert) (Cepheid, Sunnyvale, USA) and mycobacterial culture when compared with a composite reference standard (CRS).

METHODS

A retrospective single-center observational study was conducted in a tertiary care hospital in South India. Over three months, patients (aged ≥15 years) data on Xpert Ultra tests and mycobacterial culture of pulmonary and extrapulmonary samples were extracted from their electronic medical records. Patients were defined as TB cases based on the CRS criteria. Sensitivity, specificity, positive and negative predictive values of diagnostic tests were calculated by comparing them to the CRS.

RESULTS

Xpert Ultra was more sensitive (87.8%) than Xpert (72.1%) and culture (44.1%). The specificity of Xpert Ultra was lower (98.1%) than those of Xpert (100%) and culture (100%). The sensitivity (92%) and specificity (100%) of Xpert Ultra were highest when performed on pus samples.

CONCLUSIONS

Xpert Ultra with the trace category is superior to the conventional Xpert, and mycobacterial culture in identifying TB.

Diagnostic and Prognostic Value of Cerebrospinal Fluid Lactate and Glucose in HIV-Associated Tuberculosis Meningitis

The role of cerebrospinal fluid (CSF) lactate in tuberculosis meningitis (TBM) diagnosis and prognosis is unclear. The aim of this study was to evaluate the performance of CSF lactate alone and in combination with CSF glucose in predicting a diagnosis of TBM and 14-day survival. HIV-positive Ugandan adults were investigated for suspected meningitis. The baseline CSF tests included smear microscopy; Gram stain; cell count; protein; and point-of-care glucose, lactate, and cryptococcal antigen (CrAg) assays. Where CrAg was negative or there was suspicion of TBM, a CSF Xpert MTB/RIF Ultra (Xpert Ultra) test was performed. We recorded baseline demographic and clinical data and 2-week outcomes. Of 667 patients, 25% (n = 166) had TBM, and of these, 49 had definite, 47 probable, and 70 possible TBM. CSF lactate was higher in patients with definite TBM (8.0 mmol/L; interquartile ratio [IQR], 6.1 to 9.8 mmol/L) than in those with probable TBM (3.4 [IQR, 2.5 to 7.0] mmol/L), possible TBM (2.6 [IQR 2.1 to 3.8] mmol/L), and non-TBM disease (3.5 [IQR 2.5 to 5.0] mmol/L). A 2-fold increase in CSF lactate was associated with 8-fold increased odds of definite TBM (odds ratio, 8.3; 95% confidence interval [CI], 3.6 to 19.1; P < 0.01) and 2-fold increased odds of definite/probable TBM (odds ratio, 2.3; 95% CI, 1.4 to 3.7; P < 0.001). At a cut point of >5.5 mmol/L, CSF lactate could be used to diagnose definite TBM with a sensitivity of 87.7%, specificity of 80.7%, and a negative predictive value of 98.8%. CSF lactate was not predictive of 2-week mortality.

IMPORTANCE Tuberculosis meningitis (TBM) is the most severe form of tuberculosis, and its fatality is largely due to delays in diagnosis. The role of CSF lactate has not been evaluated in patients with HIV presenting with signs and symptoms of meningitis. In this study, using a point-of-care handheld lactate machine in patients with HIV-associated meningitis, we showed that high baseline CSF lactate (>5.5 mmol) may be used to rapidly identify patients with TBM and shorten the time to initiate treatment with a similar performance to the Xpert Ultra assay for definite TBM. Elevated CSF lactate levels, however, were not associated with increased 2-week mortality in patients with HIV-associated TBM. Due to moderate specificity, other etiologies of meningitis should be investigated.

Rapid Molecular Diagnosis of Extra-Pulmonary Tuberculosis by Xpert/RIF Ultra

Rapid detection of Mycobacterium tuberculosis complex and determination of drug resistance are essential for early diagnosis and treatment of tuberculosis (TB). Xpert MTB/RIF Ultra (Xpert Ultra), a molecular test that can simultaneously identify M. tuberculosis complex and resistance to rifampicin directly on clinical samples, is currently used. Xpert Ultra represents a helpful tool for rapid pulmonary TB diagnosis, especially in patients with paucibacillary infection. The aim of this review is to provide an overview of the diagnostic performance of Xpert Ultra in detection of extra-pulmonary tuberculosis.

Evaluating the efficacy of stool sample on Xpert MTB/RIF Ultra and its comparison with other sample types by meta-analysis for TB diagnostics

Precise and timely detection of tuberculosis (TB) is crucial to reduce transmission. This study aims to assess the accuracy of Xpert MTB/RIF Ultra on stool samples and systematically review the performance of Xpert MTB/RIF Ultra with different sample types by meta-analysis. Stool samples of smear-negative pulmonary TB (PTB), cervical lymph node TB, and abdominal TB patients were tested on the Xpert MTB/RIF Ultra system. Meta-analysis was performed on a set of 44 studies. Data were grouped by sample type, and the pooled sensitivity and specificity of Xpert MTB/RIF Ultra were calculated. The sensitivity of Xpert MTB/RIF Ultra with stool samples was 100% for smear-negative PTB, 27.27% for cervical lymph node TB, and 50% for abdominal TB patients, with 100% specificity for all included TB groups. The summary estimate for all PTB samples showed 84.2% sensitivity and 94.5% specificity, and EPTB samples showed 88.6% sensitivity and 96.4% specificity. Among all sample types included in our meta-analysis, urine showed the best performance for EPTB diagnosis. This pilot study supports the use of stool as an alternative non-invasive sample on Xpert MTB/RIF Ultra for rapid testing, suitable for both PTB and EPTB diagnosis.

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.

Validation of host cerebrospinal fluid protein biomarkers for early diagnosis of tuberculous meningitis in children: a replication and new biosignature discovery study

The diagnosis of tuberculous meningitis (TBM) in children is often delayed due to diagnostic difficulties. New tools are urgently needed to improve the diagnosis of the disease in this vulnerable group. The present study aimed to validate the accuracy of recently identified host cerebrospinal (CSF) biomarkers as candidates for the diagnosis of TBM in children. We collected CSF samples from 87 children aged 3 months to 13 years, that were consecutively admitted at a tertiary hospital in Cape Town, South Africa, on suspicion of having TBM. We evaluated the concentrations of 67 selected host protein biomarkers using a multiplex platform. Previously identified 3-marker (VEGF-A + IFN-γ + MPO) and 4-marker (IFN-γ + MPO + ICAM-1 + IL-8) signatures diagnosed TBM with AUCs of 0.89 (95% CI, 0.81-0.97) and 0.87 (95% CI, 0.79-0.95) respectively; sensitivities of 80.6% (95% CI, 62.5-92.5%) and 81.6% (95% CI, 65.7-92.3%), and specificities of 86.8% (71.9-95.6%) and 83.7% (70.4-92.7%) respectively. Furthermore, a new combination between the analytes (CC4b + CC4 + procalcitonin + CCL1) showed promise, with an AUC of 0.98 (95% CI, 0.94-1.00). We have shown that the accuracies of previously identified candidate CSF biomarkers for childhood TBM was reproducible. Our findings augur well for the future development of a simple bedside test for the rapid diagnosis of TBM in children.

Tuberculous meningitis: progress and remaining questions

Tuberculous meningitis is a devastating brain infection that is caused by Mycobacterium tuberculosis and is notoriously difficult to diagnose and treat. New technologies characterising the transcriptome, proteome, and metabolome have identified new molecules and pathways associated with tuberculous meningitis severity and poor outcomes that could offer novel diagnostic and therapeutic targets. The next-generation GeneXpert MTB/RIF Ultra assay, when used on CSF, offers diagnostic sensitivity for tuberculous meningitis of approximately 70%, although it is not widely available and a negative result cannot rule out tuberculous meningitis. Small trials indicate that clinical outcomes might be improved with increased doses of rifampicin, the addition of linezolid or fluoroquinolones to standard antituberculosis therapy, or treatment with adjunctive aspirin combined with corticosteroids. Large phase 3 clinical trials are underway worldwide to address these and other questions concerning the optimal management of tuberculous meningitis; these studies also form a platform for studying pathogenesis and identifying novel diagnostic and treatment strategies, by allowing the implementation of new genomic, transcriptomic, proteomic, and metabolomic technologies in nested substudies.

Extremely high levels of central nervous system involvement in miliary tuberculosis

Background

Miliary tuberculosis (TB) is one of the severest manifestations of TB that can be lethal when concomitant with the central nervous system (CNS) involvement. Bacteriological, biochemical and radiological methods for find CNS comorbidity in miliary TB was evaluated in this study.

Methods

Consecutive miliary TB adults were retrospectively enrolled from two designated TB hospitals in China. The capacities of examinations of cerebrospinal fluid (CSF), cerebral computed tomography (CT) and magnetic resonance imaging (MRI) for diagnosis of CNS involvement were assessed.

Results

Assessment of CNS involvement with a lumbar puncture and/or neuroimaging was undertaken in 282 out of 392 of acute miliary TB. Of these 282 patients, 87.59% (247/282) had CNS involvement. Cerebral contrast-enhanced MRI (96.05%, 170/177) and MRI (93.15%, 204/219) yielded significantly higher sensitivities over CSF examination (71.92%, 146/203, P < 0.001) and CT (34.69%, 17/49, P < 0.001). The sensitivity of CSF examination was superior to CT scan (P < 0.001). Although 59.65% (134/225) miliary TB patients acquired bacteriological evidence with sputum examination, the positivity was only 8.82% (21/238) for CSF examination by conventional and molecular tests.

Conclusion

Almost all miliary TB had CNS involvement and MRI demonstrated outstanding potential over other methods. Therefore, a routinely screening of CNS TB should be strongly suggested in miliary TB and MRI could be used as the initial approach in resources rich settings.

Performance of Xpert® MTB/RIF and Xpert® Ultra for the diagnosis of tuberculous meningitis in children

OBJECTIVE: To assess Xpert^® MTB/RIF (Xpert) and Xpert^® MTB/RIF Ultra (Ultra) performance in diagnosing pediatric tuberculous meningitis (TBM).METHODS: We conducted a study among children with suspected meningoencephalitis in Pune, India. Clinical, radiological, laboratory, and treatment data were analyzed to classify disease as definite, probable, possible or no TBM, using microbiologic or composite reference standards. We tested cerebrospinal fluid (CSF) either using Xpert or Ultra and estimated test performance characteristics.RESULTS: Of 341 participants, 149 (43.7%) were tested using Ultra and 192 (56.3%) with Xpert. Ultra had higher sensitivity (50% vs. 18%), lower specificity (91% vs. 99%), poor positive predictive value (PPV) (13% vs. 75%), and higher negative predictive value (NPV) (99% vs. 93%) than Xpert using the composite reference standard, with similar results by the microbiologic reference standard. Of 10 participants with trace positivity on Ultra, none met clinical TBM definitions.CONCLUSION: This is the first study to report on diagnostic performance of Ultra in pediatric TBM, which showed higher sensitivity and NPV than Xpert. For children presenting with nonspecific clinical features, Ultra is a promising diagnostic test. Further studies are required to define its optimal clinical use, including interpretation of trace positive results.

Neurocognitive outcomes of tuberculous meningitis in a primarily HIV-positive Ugandan cohort

Background: The toll of tuberculous meningitis (TBM) in both mortality and disability is considerable, but advancements in rehabilitation have the potential to improve the functional abilities and the quality of survivors' lives. However, the typical phenotype of neurocognitive impairment in TBM survivors remains unstudied in HIV-predominant populations in sub-Saharan Africa. Methods: We tested 36 survivors of TBM in Uganda with a comprehensive battery of neurocognitive assessments at 8 and 24 weeks after diagnosis, and compared results to a representative cohort of HIV-uninfected Ugandans. Results: While participants had a broad range of impairments at eight weeks, there was marked improvement by 24 weeks, when a phenotype of impairment including deficits in motor functioning, verbal learning and memory, processing speed, and executive function emerged. These deficits were present despite good clinician-rated functional status. The majority (23/27, 85%) had evidence of moderate to severe depression at week 8, and at week 24 (18/24, 75%). Conclusion: These findings highlight the need for more comprehensive neurocognitive assessment in the survivors of TBM, and further investment in and study of rehabilitation, including management of depression, to improve long-term outcomes in this population.

Comparative diagnostic utility of metagenomic next-generation sequencing, GeneXpert, modified Ziehl-Neelsen staining, and culture using cerebrospinal fluid for tuberculous meningitis: A multi-center, retrospective study in China

Background

Early diagnosis of tuberculosis meningitis (TBM) remains a great challenge during clinical practice. The diagnostic efficacies of cerebrospinal fluid (CSF)‐based mycobacterial growth indicator tube (MGIT) culture, modified Ziehl–Neelsen (ZN) staining, Xpert MTB/RIF, and metagenomic next‐generation sequencing (mNGS) for TBM remained elusive.

Methods

A total of 216 adult patients with suspicious TBM were retrospectively enrolled in this multi‐cohort study. The diagnostic performances for MGIT, modified ZN staining, Xpert MTB/RIF, and mNGS using CSF samples were evaluated.

Results

Uniform clinical case definition classified 88 (40.7%) out of 216 patients as the definite TBM, 5 (2.3%) patients as probable TBM cases, and 24 (11.1%) patients as possible TBM cases. The sensitivities of MGIT, modified ZN staining, Xpert MTB/RIF, and mNGS for TBM diagnosis against consensus uniform case definition for definite TBM were 25.0%, 76.1%, 73.9%, and 84.1%, respectively. Negative predictive values (NPVs) were 66.0%, 85.9%, 84.8%, and 90.1%, respectively. The sensitivities of MGIT, modified ZN staining, Xpert MTB/RIF, and mNGS for TBM diagnosis against consensus uniform case definition for definite, probable, and possible TBM were 18.8%, 57.3%, 55.5%, and 63.2%, respectively. Negative predictive values (NPVs) were 51.0%, 66.4%, 65.6%, and 69.7%, respectively. mNGS combined with modified ZN stain and Xpert could cover TBM cases against a composite microbiological reference standard, yielding 100% specificity and 100% NPV.

Conclusion

Metagenomic next‐generation sequencing detected TBM with higher sensitivity than Xpert, ZN staining and MGIT culture, but mNGS cannot be used as a rule‐out test. mNGS combined with Xpert or modified ZN staining could enhance the sensitivity of diagnostic tests for TBM.

Tuberculous meningitis with good outcome following appropriate timing of ventriculoperitoneal shunting for hydrocephalus

Background

Tuberculous meningitis is often associated with hydrocephalus. However, the appropriate timing for shunt placement to treat hydrocephalus remains controversial.

Case Presentation

A 43‐year‐old man presented with high fever and disturbance of consciousness. Cerebrospinal fluid (CSF) findings showed pleocytosis, increased protein levels, and hypoglycemia with an elevated pressure of 30 cm H₂O. Brain magnetic resonance imaging revealed cerebral infarctions and hydrocephalus resulting in suspicion of tuberculous meningitis. A few days after admission, external ventricular drainage was carried out for acute hydrocephalus. Four antitubercular drugs (isoniazid, rifampicin, pyrazinamide, and ethambutol) as well as dexamethasone sodium phosphate were given. The CSF polymerase chain reaction test for tuberculosis was found to be positive 2 weeks later. Once CSF protein levels improved, a ventriculoperitoneal shunting operation was undertaken.

Conclusions

When tuberculous meningitis is suspected, treatment with antitubercular drugs should be initiated prior to definitive diagnosis, and a shunt surgery should be carried out in a timely manner.

Tuberculous Meningitis in Children: Reducing the Burden of Death and Disability

Tuberculous meningitis disproportionately affects young children. As the most devastating form of tuberculosis, it is associated with unacceptably high rates of mortality and morbidity even if treated. Challenging to diagnose and treat, tuberculous meningitis commonly causes long-term neurodisability in those who do survive. There remains an urgent need for strengthened surveillance, improved rapid diagnostics technology, optimised anti-tuberculosis drug therapy, investigation of new host-directed therapy, and further research on long-term functional and neurodevelopmental outcomes to allow targeted intervention. This review focuses on the neglected field of paediatric tuberculous meningitis and bridges current clinical gaps with research questions to improve outcomes from this crippling disease.

Fujifilm SILVAMP TB LAM Assay on Cerebrospinal Fluid for the Detection of Tuberculous Meningitis in Adults With Human Immunodeficiency Virus

BACKGROUND

Tuberculous meningitis (TBM) has a high fatality rate, with inadequate diagnostic tests being a major contributor. The rollout of Xpert MTB/Rif and Xpert MTB/RIF Ultra (Xpert Ultra) have improved time-to-diagnosis with sensitivities similar to culture, yet test availability and sensitivity are inadequate. The TB lipoarabinomannan lateral flow assay (AlereLAM) offers ease of use, but its low sensitivity in cerebrospinal fluid (CSF) limits clinical utility for TBM. The Fujifilm SILVAMP TB LAM (FujiLAM) assay has excellent sensitivity in urine, but performance on cerebrospinal fluid is uncertain.

METHODS

We conducted a prospective cohort study at Kiruddu National Referral Hospital in Kampala, Uganda, enrolling patients suspected to have TBM. CSF was tested using AlereLAM, Xpert Ultra, culture, and FujiLAM. Results were compared with 2 reference standards: probable and definite TBM or definite TBM alone by the uniform TBM case definition.

RESULTS

Of 101 patients enrolled (95/101 HIV-positive), 34 had definite TBM and 24 had probable TBM. FujiLAM sensitivity on CSF was 52% (30/58) for definite or probable TBM compared with 55% (32/58) for Xpert Ultra. AlereLAM had lower sensitivity than FujiLAM in the subgroup of patients tested with both assays (14% [4/28] vs 50% [14/28]; P < .01). FujiLAM specificity was 98% (42/43) for patients without probable or definite TBM.

CONCLUSIONS

FujiLAM showed higher sensitivity than AlereLAM, with sensitivity potentially approaching that of Xpert Ultra. FujiLAM could improve time-to-treatment-initiation, especially in settings where the more technical Xpert Ultra system might not be feasible. Large confirmatory studies are needed.

Cerebrospinal Fluid Lactate as a Prognostic Marker of Disease Severity and Mortality in Cryptococcal Meningitis

BACKGROUND

Cerebrospinal fluid (CSF) lactate levels can be used to differentiate between bacterial and viral meningitis. We measured CSF lactate in individuals with cryptococcal meningitis to determine its clinical significance.

METHODS

We measured point-of-care CSF lactate at the bedside of 319 Ugandan adults living with human immunodeficiency virus at diagnosis of cryptococcal meningitis. We summarized demographic variables and clinical characteristics by CSF lactate tertiles. We evaluated the association of CSF lactate with clinical characteristics and survival.

RESULTS

Individuals with high CSF lactate >5 mmol/L at cryptococcal diagnosis more likely presented with altered mental status (P < .0001), seizures (P = .0005), elevated intracranial opening pressure (P = .03), higher CSF white cells (P = .007), and lower CSF glucose (P = .0003) compared with those with mid-range (3.1 to 5 mmol/L) or low (≤3 mmol/L) CSF lactate levels. Two-week mortality was higher among individuals with high baseline CSF lactate >5 mmol/L (35%; 38 of 109) compared with individuals with mid-range (22%; 25 of 112) or low CSF lactate (9%; 9 of 97; P =<.0001). After multivariate adjustment, CSF lactate >5 mmol/L remained independently associated with excess mortality (adjusted hazard ratio = 3.41; 95% confidence interval, 1.55-7.51; P = .002). We found no correlation between baseline CSF lactate levels and blood capillary lactate levels.

CONCLUSIONS

Baseline point-of-care CSF lactate levels are a prognostic marker of disease severity and mortality in cryptococcal meningitis. Individuals with an elevated baseline CSF lactate level are more likely to present with altered mental status, seizures, and elevated CSF opening pressure and are at a greater risk of death. Future studies are needed to determine targeted therapeutic management strategies in persons with high CSF lactate.

CSF Metabolomics of Tuberculous Meningitis: A Review

From the World Health Organization's global TB report for 2020, it is estimated that in 2019 at least 80,000 children (a particularly vulnerable population) developed tuberculous meningitis (TBM)-an invariably fatal disease if untreated-although this is likely an underestimate. As our latest technologies have evolved-with the unprecedented development of the various "omics" disciplines-a mountain of new data on infectious diseases have been created. However, our knowledge and understanding of infectious diseases are still trying to keep pace. Metabolites offer much biological information, but the insights they permit can be difficult to derive. This review summarizes current metabolomics studies on cerebrospinal fluid (CSF) from TBM cases and collates the metabolic data reported. Collectively, CSF metabolomics studies have identified five classes of metabolites that characterize TBM: amino acids, organic acids, nucleotides, carbohydrates, and "other". Taken holistically, the information given in this review serves to promote the mechanistic action of hypothesis generation that will drive and direct future studies on TBM.

Laboratory diagnosis of tuberculous meningitis in human immunodeficiency virus-seropositive patients: Correlation with the uniform case definition

Background

Laboratory confirmation of the diagnosis of tuberculous meningitis (TBM) has always been problematic. Using the uniform case definition suggested by Marais et al., we determined the sensitivity of a variety of laboratory tests.

Methods

Human immunodeficiency virus (HIV)-seropositive patients suspected of having subacute meningitis were included in the study. Using the uniform case definition, patients were divided into possible and probable cases of TBM. The following specific tests were done on the cerebrospinal fluid (CSF): layered Ziehl-Neelsen (ZN) staining, CSF culture and a panel of nucleic acid amplification tests (NAAT) consisting of the GenoType MTBDRplus assay, Cepheid Xpert MTB/RIF, the MTB Q-PCR Alert (Q-PCR) and the loop-mediated isothermal amplification (LAMP) assay. The sensitivity of each test was compared to the case definition and to each other.

Results

A total of 68 patients were evaluated. Using the uniform case definition only, without any of the specific laboratory tests, there were 15 probable cases (scores > 12) and 53 possible cases (scores 6-11) of TBM. When the uniform case definition was tested against any laboratory test, 12 of the 15 (80%) probable cases and 26 of the 53 (49.1%) possible cases had laboratory confirmation. When each test was compared to any other test, the sensitivities for the Xpert MTB/RIF, GenoType MTBDRplus, CSF culture, Q-PCR, LAMP and ZN layering were 63.2 (46.0-78.2), 76.3 (59.8-88.6), 65.7 (47.8-80.9), 81.1 (64.8-92.0), 70.3 (53.0-84.1) and 55.6 (38.1-72.1), respectively.

Conclusion

In this study, the GenoType MTBDRplus and the Q-PCR tests performed better than the Xpert MTB/RIF. Because the Xpert MTB/RIF is not good enough to 'rule out' TBM, a negative result should be followed up by another NAAT, such as the GenoType MTBDRplus or Q-PCR. The LAMP assay may be considered as the first test in resource-poor settings. At the time of the study, we did not have access to the Xpert MTB/RIF Ultra, which has now been recommended by the World Health Organization as the test of first choice. However, even this test has a similar limitation as the Xpert MTB/RIF, with two recent studies showing variable results.

Fatal tuberculous meningitis in an infant presenting with seizures in the UK

A 5-month-old male child of European background presented with sudden onset of prolonged afebrile seizures. He was intubated and transferred to the paediatric intensive care unit where he displayed abnormal neurology and remained ventilated. Brain MRI showed basal leptomeningeal enhancement suggesting malignancy or infection. Subsequent cerebrospinal fluid results of lymphocytic pleocytosis and raised protein were suggestive of tuberculous (TB) meningitis and anti-TB treatment was commenced empirically. Positive TB microbiology was eventually confirmed on respiratory secretions. The infant continued to show abnormal neurologic findings and repeated neuroimaging showed a new extensive cerebral infarct. The infant was compassionately extubated and passed away. The father was later found to have pulmonary TB. This case is an important reminder of TB meningitis for countries where TB is uncommon. The importance of considering TB in any child with abnormal neurology and of taking prompt family histories to identify children at risk is highlighted.

New management approaches to tuberculosis in people living with HIV

PURPOSE OF REVIEW

People living with HIV (PLWH) are commonly coinfected with Mycobacterium tuberculosis, particularly in high-transmission resource-limited regions. Despite expanded access to antiretroviral therapy and tuberculosis (TB) treatment, TB remains the leading cause of death among PLWH. This review discusses recent advances in the management of TB in PLWH and examines emerging therapeutic approaches to improve outcomes of HIV-associated TB.

RECENT FINDINGS

Three recent key developments have transformed the management of HIV-associated TB. First, the scaling-up of rapid point-of-care urine-based tests for screening and diagnosis of TB in PLWH has facilitated early case detection and treatment. Second, increasing the availability of potent new and repurposed drugs to treat drug-resistant TB has generated optimism about the treatment and outcome of multidrug-resistant and extensively drug-resistant TB. Third, expanded access to the integrase inhibitor dolutegravir to treat HIV in resource-limited regions has simplified the management of TB/HIV coinfected patients and minimized serious adverse events.

SUMMARY

While it is unequivocal that substantial progress has been made in early detection and treatment of HIV-associated TB, significant therapeutic challenges persist. To optimize the management and outcomes of TB in HIV, therapeutic approaches that target the pathogen as well as enhance the host response should be explored.

Neurocognitive outcomes of HIV-associated tuberculous meningitis

Background: The toll of tuberculous meningitis (TBM) in both mortality and disability is considerable, but advancements in rehabilitation have the potential to improve the functional abilities and the quality of survivors' lives. However, the typical phenotype of neurocognitive impairment in TBM survivors remains unstudied in HIV-predominant populations in sub-Saharan Africa. Methods: We tested 36 survivors of TBM in Uganda with a comprehensive battery of neurocognitive assessments at 8 and 24 weeks after diagnosis, and compared results to a representative cohort of HIV-uninfected Ugandans. Results: While participants had a broad range of impairments at eight weeks, there was marked improvement by 24 weeks, when a phenotype of impairment including deficits in motor functioning, verbal learning and memory, processing speed, and executive function emerged. These deficits were present despite good clinician-rated functional status. The majority (23/27, 85%) had evidence of moderate to severe depression at week 8, and at week 24 (18/24, 75%). Conclusion: These findings highlight the need for more comprehensive neurocognitive assessment in the survivors of TBM, and further investment in and study of rehabilitation, including management of depression, to improve long-term outcomes in this population.

Efficacy of Xpert MTB/RIF Ultra in diagnosing tuberculosis meningitis: A systematic review and meta-analysis

BACKGROUND

This study aimed to assess whether Xpert MTB/RIF Ultra (Xpert Ultra) can effectively diagnose tuberculosis meningitis (TBM) and to simultaneously compare its effectiveness with Xpert in diagnosing TBM in the same population.

METHODS

On August 12, 2020, Wanfang Database, China National Knowledge Infrastructure, Embase, Cochrane Library, and PubMed were searched for studies evaluating the diagnostic accuracy of Xpert Ultra for TBM. Then, we assessed the efficacy of Xpert Ultra against a composite reference standard and culture. If applicable, we also examined the diagnostic efficacy of Xpert in the same population. Heterogeneity was then explored by meta-regression, subgroup, and sensitivity analyses.

RESULTS

Six studies containing 601 specimens reported the diagnostic efficacy of Xpert Ultra for TBM, with a composite reference standard. No study had compared the efficacy between Xpert Ultra and culture. The pooled sensitivity of Xpert Ultra was 64% (95% confidence interval [CI]: 45-80), and the I2 value was 86% (95% CI: 76-96); its specificity for TBM was consistently 100%. In the same population, 5 studies compared the diagnostic efficacy between Xpert Ultra and Xpert for TBM. The pooled sensitivity of Xpert Ultra and Xpert was 68% (95% CI: 46-84; I2 = 87%) and 37% (95% CI: 25-50; I2 = 72%), respectively. The studies were significantly heterogeneous in terms of sensitivity but not heterogeneous in specificity.

CONCLUSIONS

Xpert Ultra was more sensitive than Xpert, but both were specific (100%). Therefore, Xpert Ultra had an excellent diagnostic efficacy for TBM, and it could be the preferred initial test for TBM.

Early Empirical Tuberculosis Treatment in HIV-Positive Patients Admitted to Hospital in South Africa: An Observational Cohort Study

BACKGROUND

Empirical tuberculosis (TB) treatment in human immunodeficiency virus (HIV)-positive inpatients is common and may undermine the impact of new diagnostics. We sought to describe empirical TB treatment and compare characteristics and outcomes with patients treated for TB after screening.

METHODS

This was a retrospective observational cohort study of HIV-positive inpatients treated empirically for TB prior to TB screening. Data on clinical characteristics, investigations, and outcomes were collected from medical records. Comparison cohorts with microbiologically confirmed or empirical TB treatment after TB screening with Xpert MTB/RIF and urine lipoarabinomannan assays were taken from South African Screening for Tuberculosis to Reduce AIDS-Related Mortality in Hospitalized Patients in Africa (STAMP) trial site. In-hospital mortality was compared using a competing-risks analysis adjusted for age, sex, and CD4 cell count.

RESULTS

Between January 2016 and September 2017, 100 patients excluded from STAMP were treated for TB empirically prior to TB screening. After enrollment in STAMP and TB screening, 240 of 1177 (20.4%) patients received TB treatment, of whom 123 had positive TB tests and 117 were treated empirically. Characteristics were similar among early empirically treated patients and those treated after TB screening. 50% of early empirical TB treatment was based on radiological investigations, 22% on cerebrospinal or pleural fluid testing, and 28% on clinical features alone. Only 11 of 100 empirically treated patients had subsequent microbiological confirmation. In-hospital mortality was lower in patients with microbiologically confirmed TB compared to those treated empirically (adjusted subdistribution hazard ratio, 0.5 [95% confidence interval, .3-.9).

CONCLUSIONS

Empirical TB treatment remains common in severely ill HIV-positive inpatients. These patients may benefit from TB screening using existing rapid diagnostics, both to improve confirmation of TB disease and reduce overtreatment for TB.

Lymphocyte-Related Immunological Indicators for Stratifying Mycobacterium tuberculosis Infection

Background

Easily accessible tools that reliably stratify Mycobacterium tuberculosis (MTB) infection are needed to facilitate the improvement of clinical management. The current study attempts to reveal lymphocyte-related immune characteristics of active tuberculosis (ATB) patients and establish immunodiagnostic model for discriminating ATB from latent tuberculosis infection (LTBI) and healthy controls (HC).

Methods

A total of 171 subjects consisted of 54 ATB, 57 LTBI, and 60 HC were consecutively recruited at Tongji hospital from January 2019 to January 2021. All participants were tested for lymphocyte subsets, phenotype, and function. Other examination including T-SPOT and microbiological detection for MTB were performed simultaneously.

Results

Compared with LTBI and HC, ATB patients exhibited significantly lower number and function of lymphocytes including CD4⁺ T cells, CD8⁺ T cells and NK cells, and significantly higher T cell activation represented by HLA-DR and proportion of immunosuppressive cells represented by Treg. An immunodiagnostic model based on the combination of NK cell number, HLA-DR⁺CD3⁺ T cells, Treg, CD4⁺ T cell function, and NK cell function was built using logistic regression. Based on receiver operating characteristic curve analysis, the area under the curve (AUC) of the diagnostic model was 0.920 (95% CI, 0.867-0.973) in distinguishing ATB from LTBI, while the cut-off value of 0.676 produced a sensitivity of 81.48% (95% CI, 69.16%-89.62%) and specificity of 91.23% (95% CI, 81.06%-96.20%). Meanwhile, AUC analysis between ATB and HC according to the diagnostic model was 0.911 (95% CI, 0.855-0.967), with a sensitivity of 81.48% (95% CI, 69.16%-89.62%) and a specificity of 90.00% (95% CI, 79.85%-95.34%).

Conclusions

Our study demonstrated that the immunodiagnostic model established by the combination of lymphocyte-related indicators could facilitate the status differentiation of MTB infection.

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.

Performance of Xpert MTB/RIF Ultra for diagnosis of pulmonary and extra-pulmonary tuberculosis, one year of use in a multi-centric hospital laboratory in Brussels, Belgium

Among the challenges in controlling tuberculosis, a rapid and accurate diagnostic test for the detection of Mycobacterium tuberculosis complex (MTBc) and its resistance to first line therapies is crucial. We evaluated the performance of the Xpert MTB/RIF Ultra assay (Xpert Ultra) for the rapid detection of MTBc and rifampicin resistance (RR) in 1120 pulmonary and 461 extra-pulmonary clinical specimens and compared it with conventional phenotypic techniques. The Xpert Ultra assay detected MTBc in 223 (14.1%) samples with an overall sensitivity and specificity, using culture as the "gold standard", of 91.1% (95% CI, 85.6-95.1) and 94.5% (95% CI, 93.1-95.6), respectively. The sensitivity of the Xpert Ultra test for smear-negative extra-pulmonary specimens was high (87.1%), even higher than with smear-negative pulmonary specimens (81.8%). But this enhanced sensitivity came with a low overall specificity of smear-negative extra-pulmonary specimens (66.7%). For 73 patients, 79/1423 (3.4%) negative mycobacterial culture samples were found to be positive with Xpert Ultra. Clinical data was necessary to correctly interpret potential false-positive results, especially trace-positive results. Sensitivity of the Xpert Ultra to detect RR compared to drug susceptibility testing was 100% (95% CI, 29.2-100) and specificity was 99.2% (95% CI, 95.8-100). We concluded that the Xpert Ultra test is able to provide a reliable TB diagnosis within a significantly shorter turnaround time than culture. This is especially true for paucibacillary samples such as smear-negative pulmonary specimens and extra-pulmonary specimens.

Sporothrix brasiliensis meningitis in an immunocompetent patient

Sporothrix brasiliensis usually causes infection limited to the skin, subcutaneous tissue and regional lymph nodes. Contamination occurs through inhalation or accidental inoculation from animal scratches and bites. Meningitis is rare and mostly occurs in immunosuppressed patients. Here, we describe an immunocompetent person who developed chronic meningitis and discuss the diagnosis, differential diagnosis and treatment of this rare condition.

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.

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.