Correlation of clinical, laboratory and drug susceptibility profiles in 176 patients with culture positive TBM in a tertiary neurocare centre

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.

Diagnostic characteristics of Xpert MTB/RIF assay for the diagnosis of tuberculous meningitis and rifampicin resistance in Southern Brazil

BACKGROUND

The timely diagnosis of tuberculous meningitis (TBM) is challenging. Molecular diagnostic tools are necessary for TBM, particularly in low- and middle-income countries.

OBJECTIVES

We aimed to calculate the diagnostics characteristics of Xpert MTB/RIF for the detection of Mycobacterium tuberculosis in the cerebrospinal fluid (CSF) and the frequency of rifampicin (RIF)-resistance in the CSF samples.

METHODS

A total of 313 consecutive CSF samples were studied and categorized into TBM definite, probable, possible, or not TBM cases based on the clinical, laboratory, and imaging data.

RESULTS

For the definite TBM cases (n=7), the sensitivity, specificity, efficiency, and positive likelihood ratio were 100, 97, 97, and 38%, respectively. However, for the TBM definite associated with the probable cases (n=24), the sensitivity decreased to 46%. All CSF samples that were Xpert MTB/RIF-positive were RIF susceptible.

CONCLUSION

Xpert MTB/RIF showed high discriminating value among the microbiology-proven TBM cases, although the values for the probable and possible TBM cases were reduced. Xpert MTB/RIF contributes significantly to the diagnosis of TBM, mainly when coupled with the conventional microbiological tests and clinical algorithms.

Microbiological diagnosis of tuberculous meningitis: Phenotype to genotype

Tuberculous meningitis (TBM) is a commonly encountered central nervous system infection. Characteristic clinical, imaging and cerebrospinal fluid parameters help clinicians to make a prompt presumptive diagnosis that enables them to start empirical anti-tuberculosis treatment. There are several close mimic to TBM, such as partially treated pyogenic meningitis, fungal meningitis, sarcoidosis, meningeal metastases and meningeal lymphomatosis. Microbiological confirmation instils a sense of confidence amongst treating physicians. With conventional phenotypic methods (cerebrospinal fluid microscopy and culture), in more than 50 per cent patients, microbiological confirmation is not achieved. Moreover, these methods take a long time before providing conclusive results. Negative result does not rule out Mycobacterium tuberculosis infection of the brain. Genotypic methods, such as IS 6110 polymerase chain reaction and automated Xpert M. tuberculosis/rifampicin (MTB/RIF) assay system improved the TBM diagnostics, as results are rapidly available. Xpert MTB/RIF assay, in addition, detects rifampicin resistance. Xpert MTB/RIF Ultra is advanced technology which has higher (60-70%) sensitivity and is being considered a game-changer in the diagnostics of TBM. A large number of TBM cases remain unconfirmed. The situation of TBM diagnostics will remain grim, if low-cost technologies are not widely available. Till then, physicians continue to rely on their clinical acumen to start empirical anti-tuberculosis treatment.

Management of complex tuberculosis cases: a focus on drug-resistant tuberculous meningitis

INTRODUCTION

Drug-resistant tuberculous meningitis has been reported worldwide. Isoniazid mono-resistance is the most frequent cause of drug-resistant tuberculous meningitis, a life-threatening disease. Extensive drug-resistant tuberculous meningitis has also been reported in some isolated case reports. Areas covered: We reviewed the current literature on drug-resistant tuberculous meningitis, as well as drug-resistant tuberculosis. Expert commentary: Drug-resistant tuberculous meningitis is a life-threatening disease and needs prompt diagnosis and treatment. Xpert MTB/RIF Ultra technology can detect Mycobacterium tuberculosis and rifampicin resistance in cerebrospinal fluid (CSF) even with low numbers of bacilli. The optimum antituberculosis drug regimen for multidrug-resistant tuberculous meningitis is largely unknown as no second-line antituberculosis drug-containing regimen has been tested in a randomized controlled fashion in drug-resistant tuberculous meningitis. A combination of levofloxacin, kanamycin, ethionamide, linezolid, and pyrazinamide would be an appropriate regimen because of excellent CSF profile of most of these drugs. End TB Strategy will help in checking the increasing challenge of drug-resistant tuberculous meningitis as it aims to eliminate all kinds of tuberculosis by the year 2035.

Validation of Mycobacterium tuberculosis real-time polymerase chain reaction for diagnosis of tuberculous meningitis using cerebrospinal fluid samples: a pilot study

Background

Timely diagnosis of tuberculous meningitis (TBM) remains challenging. Molecular diagnostic tools are necessary, particularly in low- and middle-income countries. There is no approved commercial polymerase chain reaction (PCR) assay that can be used to detect Mycobacterium tuberculosis in non-respiratory samples, such as the cerebrospinal fluid (CSF). We aimed to validate the threshold cycle (Ct) cut-off points; calculate the operational characteristics of real-time PCR for detection of M. tuberculosis (MTb qPCR) in the CSF; and the inhibitory affect of CSF red blood cells (RBC) and total proteins on MTb qPCR.

Methods

A total of 334 consecutive participants were enrolled. Based on clinical, laboratory and imaging data, cases of suspected TBM were categorized as definite, probable, possible or not TBM cases. Receiver operating characteristic curve analysis was used to select the best discriminating Ct value.

Results

For TBM cases categorized as definite or probable (n=21), the Ct validated for CSF (≤39.5) improved the diagnostic performance of MTb qPCR on CSF samples. The sensitivity was 29%, specificity was 95%, positive predictive value was 26%, negative predictive value was 95%, efficiency was 90% and positive likelihood was 5.3. The CSF RBC and total protein did not affect the positivity of the MTb qPCR.

Conclusions

These data support the validation of a highly specific but low sensitive MTb qPCR assay for the TBM diagnosis using CSF samples. MTb qPCR contributes significantly to the diagnosis, mainly when associated with conventional microbiology tests and clinical algorithms.

The application of IS6110-baced loop-mediated isothermal amplification (LAMP) in the early diagnosis of tuberculous meningitis

Here, we evaluated the potential activity of rapid Mycobacterium tuberculosis detection with loop-mediated isothermal amplification (LAMP), for the early diagnosis of tuberculous meningitis (TBM). Patients with suspected TBM from January 2014 to December 2015 were reviewed retrospectively. The cerebrospinalfluid(CSF) was collected. Acid-fast bacillus (AFB) staining, MGIT 960 culture, real-time fluorescent quantitative polymerase chain reaction (RTFQ PCR) and LAMP were performed. A total of 200 patients were included in the study. Of which, 172 of them were diagnosed with TBM (86.00%). The sensitivities of AFB staining, MGIT 960 culture, LAMP and RTFQ PCR for TBM diagnosis were 2.91% (5/172), 12.79% (22/172), 43.02% (74/172), and 34.30% (59/172), respectively. The sensitivity of LAMP for TBM was significantly higher than those of AFB staining and MGIT960 culture (χ2 = 75.11, P < 0.001; χ2 = 43.88, P = 0.002). LAMP's sensitivity was however comparable to RTFQ PCR assay (χ2 = 2.08, P = 0.130). The specificity, positive predictive value and negative predictive value of LAMP in the diagnosis of TBM were 92.86% (26/28), 97.37% (74/76) and 20.97 % (26/124), respectively. The overall consistency between LAMP and RTFQ PCR in the diagnosis of TBM was 88.5% (177/200), with Kappa value of 0.870. The consistency between LAMP and MGIT960 culture was 71% (142/200), with Kappa value of 0.730. Among all the methods, LAMP had high sensitivity, specificity and positive predictive value, showing high consistency with MGIT960 culture and RTFQ PCR.