Xpert® MTB/RIF assay for extrapulmonary tuberculosis and rifampicin resistance

Biomarkers in diagnosing and therapeutic monitoring of tuberculosis: a review

Tuberculosis (TB) continues to pose a significant health challenge worldwide, emphasizing the importance of prompt diagnosis and efficient monitoring of treatment outcomes for effective disease control. Biomarkers have become increasingly important in the realm of TB diagnoses and treatment. The objective of this comprehensive review is to examine the present state of biomarkers employed in the diagnosis of TB, monitoring the response to treatment, and predicting treatment outcomes. In this study, we undertake a comprehensive examination of the diverse biomarkers utilized in TB diagnoses, spanning molecular, immunological, and other novel methodologies. Furthermore, we examine the potential of biomarkers in the context of therapeutic monitoring, assessment of treatment effectiveness, and anticipation of drug resistance. Additionally, this paper presents future prospects regarding the utilization of biomarkers in the therapy of tuberculosis.

The value of histopathologic examination and Xpert (MTB/RIF) assay in diagnosis of cervical lymph node tuberculosis after coarse needle biopsy guided by CEUS: a retrospective analysis of 612 cases

OBJECTIVE

To investigate the value of histopathological examination (HPE) and Xpert Mycobacterium tuberculosis bacilli/rifampicin (MTB/RIF) assay in diagnosis of cervical lymph node tuberculosis (LN TB) after coarse needle biopsy (CNB).

METHODS

We retrospectively analyzed 612 samples obtained from October 2017 to August 2023 from patients suspected cervical LN TB with surgically pathological, microbial culture confirmed, and clinically confirmed cervical lymph node enlargement who received ultrasound-guided CNB assisted by contrast-enhanced ultrasound (CEUS) at our hospital. All specimens were assessed by HPE and the Xpert (MTB/RIF) assay. We analyzed the results to determine the diagnostic value of HPE and Xpert (MTB/RIF) assay in samples taken after CEUS-assisted CNB of LN TB, and to evaluate the safety of CNB.

RESULTS

Based on the comprehensive reference standard established in this study, 532 of 612 patients were diagnosed with cervical LN TB, of which 476 were CNB positive cases, the positive rate of diagnosis was 89.5%。The sensitivity, specificity, positive predictive value, negative and predictive value of HPE were 80.4%, 91.2%, 98.4%, 41.2% respectively, while those of the Xpert MTB/RIF assay were 75.7%, 98.7%, 99.7%, 38.0% respectively. No postoperative complications were noted, and the Clavien-Dindo grade was 2.

CONCLUSION

CEUS-assisted CNB has high diagnostic value and is safe for cervical LN TB. The sensitivity of HPE is slightly higher than that of Xpert (MTB/RIF) assay, and the specificity of Xpert (MTB/RIF) assay is higher than that of HPE, so Xpert (MTB/RIF) assay can correct the cervical lymph node tuberculosis with negative HPE.

Utility of Cerebrospinal Fluid Unstimulated Interferon-Gamma (IRISA-TB) as a Same-Day Test for Tuberculous Meningitis in a Tuberculosis-Endemic, Resource-Poor Setting

Background

Tuberculous meningitis (TBM) mortality is high and current diagnostics perform suboptimally. We evaluated the diagnostic performance of a DNA-based assay (GeneXpert Ultra) against a new same-day immunodiagnostic assay that detects unstimulated interferon-gamma (IRISA-TB).

Methods

In a stage 1 evaluation, IRISA-TB was evaluated in biobanked samples from Zambia (n = 82; tuberculosis [TB] and non-TBM), and specificity in a South African biobank (n = 291; non-TBM only). Given encouraging results, a stage 2 evaluation was performed in suspected TBM patients from Zimbabwe and Malawi (n = 668). Patients were classified as having definite, probable or possible TBM, or non-TBM based on their microbiological results, cerebrospinal fluid (CSF) chemistry, and whether they received treatment.

Results

In the stage 1 evaluation, sensitivity and specificity of IRISA-TB were 75% and 87% in the Zambian samples, and specificity was 100% in the South African samples. In the stage 2 validation, IRISA-TB sensitivity (95% confidence interval [CI]) was significantly higher than Xpert Ultra (76.2% [55.0%-89.4%] vs 25% [8.9%-53.3%]; P = .0048) when trace readouts were considered negative. Specificity (95% CI) was similar for both assays (91.4% [88.8%-93.4%] vs 86.9% [83.4%-89.8%]). When the Xpert Ultra polymerase chain reaction product was verified by sequencing, the positive predictive value of trace readouts in CSF was 27.8%. Sensitivity of IRISA-TB was higher in human immunodeficiency virus (HIV)-infected versus uninfected participants (85.8% vs 66.7%).

Conclusions

As a same-day rule-in test, IRISA-TB had significantly better sensitivity than Xpert Ultra in a TB/HIV-endemic setting. An immunodiagnostic approach to TBM is promising, and further studies are warranted.

Establishment and Validation of a Nomogram for Identifying False Positives in Xpert MTB/RIF Rifampicin Resistance Test

Purpose

This study aimed to establish and validate a diagnostic nomogram for identifying false positives in the Xpert MTB/RIF (Xpert) for detection of rifampicin resistance (RIF-R).

Patients and Methods

In this retrospective study, we collected basic patient characteristics and various clinical information from the electronic medical record database. Patients were randomly divided into training and validation groups in a 7:3 ratio. LASSO regression was used to screen variables and construct a diagnostic nomogram. The ROC curve, calibration curve, and decision curve analysis (DCA) were used to evaluate the performance of the nomogram.

Results

A total of 384 patients were included in the study, with 268 and 116 patients in the training and validation cohorts, respectively. Finally, probe mutations and probe delay were identified as the independent influencing factors. Using the mutation of probe E as a reference, probes A or C (OR = 51.07, P<0.001), probe D (OR = 7.48, P<0.001), and multiple probes (OR = 4.42, P=0.029) were identified as factors influencing false positives in Xpert for detection of RIF-R. Taking probe delay ΔCT <4 as a reference, ΔCT (4-5.9) (OR = 17.06, P=0.005) and ΔCT (6-7.9) (OR = 36.67, P<0.001) were noted to be the factors influencing false positives in Xpert for detection of RIF-R. Based on these two variables, we constructed a diagnostic nomogram. The area under the curve of the nomogram model was 0.847 and 0.850 for the training and validation groups, respectively. The calibration curves were consistent. The DCA revealed that the model achieved the greatest net benefit when the threshold probability was set between 6% and 71% in the training cohort and 6% and 70% in the validation cohort.

Conclusion

The nomogram constructed can identify false positives in Xpert for detection of RIF-R and provides basis for clinicians to formulate diagnosis and treatment plans.

ISCCM Position Statement on the Approach to and Management of Critically Ill Patients with Tuberculosis

Tuberculosis (TB) is an important cause of morbidity and mortality globally. About 3-4% of hospitalized TB patients require admission to the intensive care unit (ICU); the mortality in these patients is around 50-60%. There is limited literature on the evaluation and management of patients with TB who required ICU admission. The Indian Society of Critical Care Medicine (ISCCM) constituted a working group to develop a position paper that provides recommendations on the various aspects of TB in the ICU setting based on available evidence. Seven domains were identified including the categorization of TB in the critically ill, diagnostic workup, drug therapy, TB in the immunocompromised host, organ support, infection control, and post-TB sequelae. Forty-one questions pertaining to these domains were identified and evidence-based position statements were generated, where available, keeping in focus the critical care aspects. Where evidence was not available, the recommendations were based on consensus. This position paper guides the approach to and management of critically ill patients with TB.

How to cite this article

Chacko B, Chaudhry D, Peter JV, Khilnani G, Saxena P, Sehgal IS, et al. isccm Position Statement on the Approach to and Management of Critically Ill Patients with Tuberculosis. Indian J Crit Care Med 2024;28(S2):S67-S91.

Analysis of unsuccessful tests and the effect of prolonged clinical sample preprocessing in the GeneXpert MTB/RIF assay

BACKGROUND

The GeneXpert MTB/RIF (Xpert) assay is a widely used technology for detecting Mycobacterium tuberculosis (MTB) in clinical samples. However, the study on the failure of the Xpert assay during routine implementation and its potential solutions is limited.

METHODS

We retrospectively analyzed the records of unsuccessful tests in the Xpert and the GeneXpert MTB/RIF Ultra (Ultra) assays between April 2017 and April 2021 at the Shanghai Public Health Clinical Center. To further investigate the effect of prolonged preprocessing on clinical sputum, an additional 120 sputum samples were collected for Xpert testing after 15 min, 3 h, and 6 h preprocessing. The analysis was performed by SPSS version 19.0 software.

RESULTS

A total of 11,314 test records were analyzed, of which 268 (2.37%) had unsuccessful test results. Among these, 221 (1.95%) were reported as "Error", 43 (0.38%) as "Invalid", and 4 (0.04%) as "No result". The most common clinical specimen for Xpert tests was sputum, accounting for 114 (2.17%) unsuccessful tests. The failure rate of urine specimens was lower than that of sputum (OR = 0.12, 95% CI: 0.02-0.88, χ2 = 6.22, p = 0.021). In contrast, the failure rate of stool specimens was approximately twice as high as that of sputum (OR = 1.93, 95% CI: 1.09-3.40, χ2 = 5.35, p = 0.014). In the prolonged preprocessing experiment, 102 cases (85%) yielded consistent results in Xpert tests. Furthermore, 7 cases (5.83%) detected an increase in MTB load, 8 cases (6.67%) detected a decrease in MTB load, and 3 cases (2.5%) yielded incongruent results in MTB and rifampicin resistance detection.

CONCLUSIONS

The primary cause of unsuccessful tests in the Xpert assay was reported as "Error". Despite varying failure rates depending on the samples, the Xpert assay can be applied to extrapulmonary samples. For paucibacillary specimens, retesting the remaining preprocessed mixture should be carefully considered.

Multi-centric evaluation of Truenat MTB and MTB-RIF Dx assays for diagnosis of extrapulmonary tuberculosis

Extra-pulmonary TB (EPTB) is difficult to diagnose due to paucibacillary nature of disease. Current study evaluated accuracy of Truenat MTB and MTB-Rif Dx (TN), for detection of Mycobacterium tuberculosis and resistance to rifampicin. Samples were collected from 2103 treatment naive adults with presumptive EPTB, and tested by smear microscopy, liquid culture (LC) (MGIT-960) and GeneXpert MTB/RIF (GX) (Microbiological Reference Standards, MRS). TN results were compared to MRS and Composite Reference Standards (CRS, Microbiology, histopathology, radiology, clinical features prompting decision to treat, response to treatment). CRS grouped patients into 551 confirmed, 1096 unconfirmed, and 409 as unlikely TB. TN sensitivity and specificity was 73.7% and 90.4% against GX. Against LC, Overall sensitivity of GX was 67.6%, while that of TN was 62.3%. Highest sensitivity by TN was observed in pus samples (89%) and highest specificity (92%) in CSF samples, similar to GX. TN sensitivity was better in fluid and biopsy samples and slightly inferior for lymph node aspirates compared to GX. TN sensitivity for RIF resistance detection was slightly superior to GX. TN and GX results were further compared to Clinical Reference Standards. TN detected 170 TB patients initiated on treatment missed by GX, while GX detected 113 such patients missed by TN. Of 124 samples with RIF resistance discordance between GX and TN, GX reported 103/124 as sensitive, 3/124 as indeterminate and 18 as resistant (13/18 samples had low/very low DNA load) while TN reported RIF resistance indeterminate in 103/111 low/very low DNA load samples. Due to paucibacillary nature of EPTB samples, culture yield was poor and phenotypic drug susceptibility testing failed to resolve the discordance. The study establishes TN at par with GX and can be utilized for quick and accurate diagnosis of EPTB.

Blood RNA signatures outperform CRP triage of tuberculosis lymphadenitis and pericarditis

Background

Limited data are available on the diagnostic accuracy of blood RNA biomarker signatures for extrapulmonary TB (EPTB). We addressed this question among people investigated for TB lymphadenitis and TB pericarditis, in Cape Town, South Africa.

Methods

We enrolled 440 consecutive adults referred to a hospital for invasive sampling for presumptive TB lymphadenitis (n=300) or presumptive TB pericarditis (n=140). Samples from the site of disease underwent culture and/or molecular testing for Mycobacterium tuberculosis complex (Mtb). Discrimination of patients with and without TB defined by microbiology or cytology reference standards was evaluated using seven previously reported blood RNA signatures by area under the receiver-operating characteristic curve (AUROC) and sensitivity/specificity at predefined thresholds, benchmarked against blood C-reactive protein (CRP) and the World Health Organization (WHO) target product profile (TPP) for a TB triage test. Decision curve analysis (DCA) was used to evaluate the clinical utility of the best performing blood RNA signature and CRP.

Results

Data from 374 patients for whom results were available from at least one microbiological test from the site of disease, and blood CRP and RNA measurements, were included. Using microbiological results as the reference standard in the primary analysis (N=204 with TB), performance was similar across lymphadenitis and pericarditis patients. In the pooled analysis of both cohorts, all RNA signatures had comparable discrimination with AUROC point estimates ranging 0.77-0.82, superior to that of CRP (0.61, 95% confidence interval 0.56-0.67). The best performing signature (Roe3) achieved an AUROC of 0.82 (0.77-0.86). At a predefined threshold of 2 standard deviations (Z2) above the mean of a healthy reference control group, this signature achieved 78% (72-83%) sensitivity and 69% (62-75%) specificity. In this setting, DCA revealed that Roe3 offered greater net benefit than other approaches for services aiming to reduce the number needed to investigate with confirmatory testing to <4 to identify each case of TB.

Interpretation

RNA biomarkers show better accuracy and clinical utility than CRP to trigger confirmatory TB testing in patients with TB lymphadenitis and TB pericarditis, but still fall short of the WHO TPP for TB triage tests.

Funding

South African MRC, EDCTP2, NIH/NIAID, Wellcome Trust, NIHR, Royal College of Physicians London.

Research in context

Evidence before this study: Blood RNA biomarker signatures and CRP measurements have emerged as potential triage tests for TB, but evidence is mostly limited to their performance in pulmonary TB. Microbiological diagnosis of extrapulmonary TB (EPTB) is made challenging by the need for invasive sampling to obtain tissue from the site of disease. This is compounded by lower sensitivity of confirmatory molecular tests for EPTB compared to their performance in pulmonary disease. We performed a systematic review of diagnostic accuracy studies of blood RNA biomarkers or CRP measurements for EPTB, which could mitigate the need for site-of-disease sampling for the diagnosis of TB. We searched PubMed up to 1 st August 2023, using the following criteria: "extrapulmonary [title/abstract] AND tuberculosis [title/abstract] AND biomarker [title/abstract]". Although extrapulmonary TB was included in several studies, none focused specifically on EPTB or included an adequate number of EPTB cases to provide precise estimates of test accuracy. Added value of this study: To the best of our knowledge, we report the first diagnostic accuracy study of blood RNA biomarkers and CRP for TB among people with EPTB syndromes. We examined the performance of seven previously identified blood RNA biomarkers as triage tests for TB lymphadenitis and TB pericarditis compared to a microbiology reference standard among people referred to hospital for invasive sampling in a high TB and HIV prevalence setting. Multiple blood RNA biomarkers showed comparable diagnostic accuracy to that previously reported for pulmonary TB in both EPTB disease cohorts, irrespective of HIV status. All seven blood RNA biomarkers showed superior diagnostic accuracy to CRP for both lymphadenitis and pericarditis, but failed to meet the combined >90% sensitivity and >70% specificity recommended for a blood-based diagnostic triage test by WHO. Nonetheless, in decision curve analysis, an approach of using the best performing blood RNA biomarker to trigger confirmatory microbiological testing showed superior clinical utility in clinical services seeking to reduce the number needed to test (using invasive confirmatory testing) to less than 4 for each EPTB case detected. If acceptable to undertake invasive testing in more than 4 people for each true case detected, then a test-all approach will provide greater net benefit in this TB/HIV hyperendemic setting.Implications of all the available evidence: Blood RNA biomarkers show some potential as diagnostic triage tests for TB lymphadenitis and TB pericarditis, but do not provide the level of accuracy for blood-based triage tests recommended by WHO for community-based tests. CRP has inferior diagnostic accuracy to blood RNA biomarkers and cannot be recommended for diagnostic triage among people with EPTB syndromes referred for invasive sampling.

[Evaluation of molecular diagnosis of tuberculosis and resistance to rifampicin with GeneXpert® MTB/RIF in Algeria]

Objective

1) To evaluate the contribution of the GeneXpert® MTB/RIF (GX) test in the diagnosis of pulmonary and extra-pulmonary tuberculosis compared to culture. 2) To compare the rifampicin results resistance obtained by GX with the phenotypic sensitivity test.

Materials and methods

Retrospective study carried out over a period of five years, from May 2017 to June 2022 at the microbiology laboratory of the Central army Hospital Mohamed Seghir Nekkache, Algiers (Algeria). The pulmonary and extrapulmonary clinical specimens were collected, cultivated, tested by GX PCR and direct examination by Ziehl-Neelsen staining. The study of sensitivity to antituberculosis drugs was performed according to the proportion method on liquid medium Bactec MGIT 960 (or on solid medium Lowenstein-Jensen at the Algerian Pasteur Institute).

Results

310 samples were included in the final analysis of the study, of which 156 were of pulmonary origin and 154 of extrapulmonary origin. Mycobacterium tuberculosis complex (MTBC) was detected in 95 samples from 88 tuberculosis patients (sex ratio 2,03 and middle age 37 years) with 49 cases of pulmonary tuberculosis and 39 cases of extra-pulmonary tuberculosis. For 2 cases, the GX was positive while the culture was negative and for 11 cases, the GX was negative while the culture was positive. Thus, in our study and compared to culture, GX showed an overall sensitivity of 88.2%, a specificity of 98.6%, a positive predictive value (PPV) of 96.4% and a negative predictive value (NPV) of 95.2%. The analysis of the data according to the type of samples, the sensitivity, specificity, PPV and NPV of GX for the pulmonary and extrapulmonary samples were 96.3% vs. 77.0%, 98.0% vs. 99.1%, 96.2% vs. 96.5% and 98.0% vs. 92.7% respectively. The sensitivity of GX for disco-vertebral, lymph node, meningeal and pleural tuberculosis were 100%, 90.0%, 71.4% and 57.1% respectively. The sensitivity of GX for pulmonary tuberculosis compared to microscopy was 96% vs. 68%. The comparison of the results of detection of resistance to rifampicin by GX and by phenotypic methods showed perfect agreement.

Discussion and conclusion

A good sensitivity of GX compared to microscopy was revealed. The GX is a useful tool for the diagnosis of pulmonary tuberculosis, especially in smear-negative cases. The sensitivity of GX in extrapulmonary tuberculosis varied depending on the location of the infection. A negative result by GX does not exclude tuberculosis and cases of resistance to RIF detected by GX must be confirmed by phenotypic method.

Factors influencing false-positive results of rifampicin resistance detected by Xpert MTB/RIF: A retrospective study in Zhejiang, China

Objective

This study aimed to explore the factors influencing false-positive results for rifampicin resistance (RIF-R) detected using Xpert MTB/RIF (Xpert).

Methods

This retrospective analysis included the clinical data of patients from September 2019 to February 2023. The chi-square and rank sum tests were used to compare differences in patient characteristics between the true-positive and false-positive groups. Logistic regression was used to analyze the factors influencing false positives in the detection of RIF-R by Xpert.

Results

A total of 384 patients were included. Logistic regression analysis revealed that, with mutation of probe E as the reference, mutations on probe A or C (OR = 72.68, P < 0.001), probe D (OR = 6.44, P < 0.001), and multiple probes (OR = 5.94, P = 0.002) were associated with false-positive results in Xpert detection of RIF-R. Taking probe delay ΔCt <4 as the reference, ΔCt (4-5.9) (OR = 13.54, P < 0.001), ΔCt (6-7.9) (OR = 48.08, P < 0.001) probe delays were associated with false positives in Xpert detection of RIF-R. When very low quantification is accompanied by a probe delay, the probability of false-positive RIF-R detection can reach 80 %.

Conclusions

Clinicians should consider factors such as probe mutation type, probe delay, and very low quantification accompanied by probe delay when interpreting Xpert results, which can reduce the misdiagnosis of tuberculosis drug resistance.

Using cerebrospinal fluid nanopore sequencing assay to diagnose tuberculous meningitis: a retrospective cohort study in China

OBJECTIVE

This study aimed to evaluate the efficiency of nanopore sequencing for the early diagnosis of tuberculous meningitis (TBM) using cerebrospinal fluid and compared it with acid-fast bacilli (AFB) smear, mycobacterial growth indicator tube culture and Xpert Mycobacterium tuberculosis (MTB)/rifampicin (RIF).

DESIGN

Single-centre retrospective study.

SETTING

The Tuberculosis Diagnosis and Treatment Center of Zhejiang Chinese and Western Medicine Integrated Hospital.

PARTICIPANTS

We enrolled 64 adult patients with presumptive TBM admitted to our hospital from August 2021 to August 2023.

METHODS

We calculated the sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of AFB smear, culture, Xpert MTB/RIF and nanopore sequencing to evaluate their diagnostic efficacy compared with a composite reference standard for TBM.

RESULTS

Among these 64 patients, all tested negative for TBM by AFB smear. The sensitivity, specificity, PPV and NPV were 11.11%, 100%, 100% and 32.2% for culture, 13.33%, 100%, 100% and 2.76% for Xpert MTB/RIF, and 77.78%, 100%, 100% and 65.52% for nanopore sequencing, respectively.

CONCLUSION

The diagnostic accuracy of the nanopore sequencing test was significantly higher than that of conventional testing methods used to detect TBM.

Diagnosis and management of severe pulmonary and extrapulmonary tuberculosis in critically ill patients: A mini review for clinicians

Among critically ill patients, severe pulmonary and extrapulmonary tuberculosis has high morbidity and mortality. Yet, it is a diagnostic challenge given its nonspecific clinical symptoms and signs in early stages of the disease. In addition, management of severe pulmonary and extrapulmonary tuberculosis is complicated given the high risk of drug-drug interactions, drug-disease interactions, and adverse drug reactions. To help clinicians acquire an up-to-date approach to severe tuberculosis, this paper will provide a narrative review of contemporary diagnosis and management of severe pulmonary and extrapulmonary tuberculosis in critically ill patients.

Diagnosis of Paediatric Extrapulmonary Tuberculosis by the MPT64 Antigen at a Tertiary Care Hospital

Background Tuberculosis (TB) remains a global health concern, with India bearing a substantial burden. Paediatric TB, especially extrapulmonary TB (EPTB), presents unique diagnostic challenges due to its paucibacillary nature and the difficulty in obtaining suitable samples in children. Accurate and timely diagnosis is crucial to initiate appropriate treatment and mitigate disease spread. The MPT64 antigen test has shown promise in diagnosing TB, but its performance in paediatric EPTB remains underexplored. This study aimed to evaluate the diagnostic utility of the MPT64 antigen test in paediatric EPTB cases at a tertiary care hospital in India. Methods We conducted a prospective cross-sectional study at the Indira Gandhi Institute of Medical Sciences (IGIMS), a tertiary care hospital in India. A total of 250 paediatric participants, aged 0-18 years, with clinical suspicion of extrapulmonary tuberculosis (EPTB) were included. Diagnostic samples (e.g., tissue biopsies, pus, cerebrospinal fluid (CSF), and lymph node aspirates) were obtained, and tests including microscopy for acid-fast bacilli (AFB), mycobacterial cultures, GeneXpert MTB/RIF assay, and the TB Antigen MPT64 Rapid ICT Kit were performed. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and diagnostic accuracy of the MPT64 antigen test were calculated using culture and GeneXpert as reference standards. Results Among the 250 participants, 34 (13.6%) were confirmed to have EPTB. The MPT64 antigen test demonstrated a sensitivity of 70.6% and specificity of 92.1% in detecting EPTB cases. Mycobacterial cultures had the highest sensitivity (91.2%) and specificity (97.7%). GeneXpert showed a sensitivity of 70.6% and specificity of 93.9%. Overall diagnostic accuracy ranged from 88.7% for acid-fast bacteria (AFB) staining to 96.9% for mycobacterial cultures. The MPT64 antigen test had an area under the curve (AUC) of 0.814, indicating a good diagnostic accuracy. Conclusion The MPT64 antigen test demonstrates promising sensitivity and specificity for diagnosing paediatric EPTB, making it a valuable diagnostic tool, especially in resource-limited settings. However, mycobacterial cultures maintain the highest accuracy. Combining the MPT64 antigen test with other methods may enhance diagnostic capabilities.

Tuberculosis prostate abscess: molecular diagnostic testing

Introduction

Urogenital tuberculosis (UGTB) is a frequent presentation of extrapulmonary tuberculosis. Recognizing this condition is paramount for healthcare providers, especially in patients living with human immunodeficiency virus (HIV), as it significantly influences both mortality and quality of life.

Case report

Case report This report presents the case of a 57-year-old male patient diagnosed with de novo HIV infection who presented with respiratory and urinary symptoms, and prostate abscess in a computed tomography. He was ultimately diagnosed with a tuberculous prostate abscess through real-time polymerase chain reaction.

Conclusions

Conclusions This case underscores the importance of utilizing molecular diagnostic tools in identifying UGTB, shedding light on their invaluable role in timely diagnosis.

Performance of metagenomic next-generation sequencing in cerebrospinal fluid for diagnosis of tuberculous meningitis

Purpose. Metagenomic next-generation sequencing (mNGS) has been widely used in the diagnosis of infectious diseases, while its performance in diagnosis of tuberculous meningitis (TBM) is incompletely characterized. The aim of this study was to assess the performance of mNGS in the diagnosis of TBM, and illustrate the sensitivity and specificity of different methods.Methods. We retrospectively recruited TBM patients between January 2021 and March 2023 to evaluate the performance of mNGS on cerebrospinal fluid (CSF) samples, in comparison with conventional microbiological testing, including culturing of Mycobacterium tuberculosis (MTB), acid-fast bacillus (AFB) stain, reverse transcription PCR and Xpert MTB/RIF.Results. Of the 40 enrolled, 34 participants were diagnosed with TBM, including 15(44.12 %) definite and 19(55.88 %) clinical diagnosis based upon clinical manifestations, CSF parameters, brain imaging, pathogen evidence and treatment response. The mNGS method identified sequences of Mycobacterium tuberculosis complex (MTBC) in 11 CSF samples. In patients with definite TBM, the sensitivity, specificity, positive predictive value, negative predictive value and accuracy of mNGS were 78.57, 100, 100, 66.67 and 85 %, respectively. Compared to conventional diagnostic methods, the sensitivity of mNGS (78.57 %) was higher than AFB (0 %), culturing (0 %), RT-PCR (60 %) and Xpert MTB/RIF (14.29 %).Conclusions. Our study indicates that mNGS of CSF exhibited an overall improved sensitivity over conventional diagnostic methods for TBM and can be considered a front-line CSF test.

Usefulness of Xpert MTB/RIF Ultra for rapid diagnosis of extrapulmonary tuberculosis in Tunisia

Extrapulmonary tuberculosis (EPTB) remains a challenging diagnosis. The purpose of this study was to assess the accuracy of Xpert MTB/RIF Ultra (Cepheid, USA) for rapid diagnosis of EPTB in Tunisia. Eight hundred and forty-seven extrapulmonary samples collected from 2017 to 2021, were subjected to Xpert MTB/RIF Ultra. Microscopy and culture were performed for all the specimens. The accuracy of Xpert Ultra was evaluated in comparison to the culture. Xpert Ultra diagnosed EPTB with a global sensitivity of 80.66% (74.3-85.75) and specificity of 70.87% (67.31-74.20). The molecular test was most accurate when performed in cerebrospinal fluids, bones and joints and cutaneous specimens showing a sensitivity of 100% and a specificity ranging from 70.60 to 91.11%. In lymph node samples comprising aspirates and biopsies, the sensitivity of Xpert Ultra was high 87.50% (77.23-93.53), however, the specificity was 51.08% (44.67-57.46). For pleural samples, the Xpert Ultra sensitivity was 77.50% (68.34-84.68) ranging from 71.43 to 80% in pleural biopsies and fluids respectively. The specificity in all pleural specimens was 79.56% (74.40-83.91). Xpert Ultra showed promise in the diagnosis of EPTB. The performances varied according to the site of the disease. The test may be more valuable if used in combination with other diagnostic modalities.

The tuberculous pleural effusion

Pleural tuberculosis (TB) is a common entity with similar epidemiological characteristics to pulmonary TB. It represents a spectrum of disease that can variably self-resolve or progress to TB empyema with severe sequelae such as chronic fibrothorax or empyema necessitans. Coexistence of and progression to pulmonary TB is high. Diagnosis is challenging, as pleural TB is paucibacillary in most cases, but every effort should be made to obtain microbiological diagnosis, especially where drug resistance is suspected. Much attention has been focussed on adjunctive investigations to support diagnosis, but clinicians must be aware that apparent diagnostic accuracy is affected both by the underlying TB prevalence in the population, and by the diagnostic standard against which the specified investigation is being evaluated. Pharmacological treatment of pleural TB is similar to that of pulmonary TB, but penetration of the pleural space may be suboptimal in complicated effusions. Evidence for routine drainage is limited, but evacuation of the pleural space is indicated in complicated disease.

Educational aims

To demonstrate that pleural TB incorporates a wide spectrum of disease, ranging from self-resolving lymphocytic effusions to severe TB empyema with serious sequelae.To emphasise the high coexistence of pulmonary TB with pleural TB, and the importance of obtaining sputum for culture (induced if necessary) in all cases.To explore the significant diagnostic challenges posed by pleural TB, and consequently the frequent lack of information about drug sensitivity prior to initiating treatment.To highlight the influence of underlying TB prevalence in the population on the diagnostic accuracy of adjunctive investigations for the diagnosis of pleural TB.To discuss concerns around penetration of anti-TB medications into the pleural space and how this can influence decisions around treatment duration in practice.

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.

The value of histopathology combined with CapitalBio Mycobacterium real-time polymerase chain reaction test for diagnosing spinal tuberculosis

Purpose

To evaluate the diagnostic efficacy of CapitalBio Mycobacterium real-time polymerase chain reaction assay (CapitalBio test) in spinal tuberculosis (STB). The value of histopathology combined with the CapitalBio test in diagnosing STB was also assessed.

Methods

We retrospectively analyzed the medical information of suspected STB. The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and area under the curve (AUC) of histopathology, CapitalBio test, and histopathology combined with CapitalBio test were calculated to evaluate their diagnostic efficacy compared with a composite reference standard.

Results

A total of 222 suspected STB patients were included in the study. The sensitivity, specificity, PPV, NPV, and AUC of histopathology for STB were recorded to be 62.0, 98.0, 97.4, 68.3%, and 0.80, respectively. The sensitivity, specificity, PPV, NPV, and AUC of the CapitalBio test were 75.2, 98.0, 97.9, 76.7%, and 0.87, respectively, while that of histopathology combined with the CapitalBio test was 81.0, 96.0, 96.1, 80.8%, and 0.89, respectively.

Conclusion

Histopathology and CapitalBio test exhibited high accuracy and are recommended in diagnosing STB. Histopathology combined with the CapitalBio test might give the best efficacy in STB diagnosis.

Comparison of Performances of GeneXpert MTB/RIF, Bactec MGIT 960, and Bactec Myco/F Systems in Detecting Mycobacterium tuberculosis in Biopsy Tissues: a Retrospective Study

Tuberculosis remains a major global public concern as a leading cause of health care-associated infections. The detection of Mycobacterium tuberculosis (MTB) is challenging due to the paucibacillary nature of the pathogen. For suspected pulmonary and extrapulmonary tuberculosis patients, if sputum, bronchoalveolar lavage fluid (BALF), related samples are negative for MTB, or suspected tumors, biopsy tissues may provide a better diagnostic yield. This study was aimed at comparing the performances of three methods in identifying MTB in biopsy tissues, including the Bactec mycobacterial growth indicator tube 960 (MGIT 960) system, the GeneXpert MTB/RIF assay (GeneXpert), and the Bactec Myco/F lytic culture (Myco/F) system. Biopsy samples from 3,209 nonduplicated patients were retrospectively enrolled between January 2018 and September 2021, of which 180 (5.6%) were positive for MTB by at least one method. GeneXpert revealed the highest recovery rate (134/162, 82.7%), followed by MGIT 960 (99/135, 73.3%) and Myco/F (26/143, 18.1%), and the composite positive rate for GeneXpert and MGIT 960 was 96.6% (173/179). Pairwise comparisons were conducted after completion of both tests, and the results showed that Myco/F had significantly lower detection rates than GeneXpert and MGIT 960 (16.4% versus 82.8%, P < 0.001; 14.3% versus 71.4%, P < 0.001). In summary, GeneXpert was the most sensitive and recommended method for MTB detection in biopsy tissues, and the combination of GeneXpert and MGIT 960 could improve the overall diagnostic yield. IMPORTANCE Mycobacterium tuberculosis (MTB) poses a severe threat to public health worldwide. The diagnosis of tuberculosis is challenging due to the low load of the microorganism in samples. Biopsy tissues are sometimes collected via invasive procedures with limited size, and additional samples are often inaccessible. The GeneXpert MTB/RIF assay, Bactec MGIT 960 system, and Bactec Myco/F lytic system have been used in detecting MTB in our laboratory. Here, we evaluated the performances of these three methods in 3,209 biopsy tissues samples to establish a more effective protocol based on clinical requirements. Attempts for a locally optimized protocol should be always made.

Extra-long treatment of MDR-TB osteomyelitis of humerus due to neurotoxicity from the 2nd-line drugs: a case report

Infection with tuberculosis (TB) still considered a leading infectious cause of death, osteomyelitis TB rare entity, and being extraspinal MDR-TB make it very rare case; most of experience in treating osteomyelitis TB was derived from pulmonary TB experience, and we present a case of humerus MDR-TB that was treated for 5 years, with several interruption due to side effect and other causes.

Comparison of the conventional tube and erythrocyte-magnetized technology in titration of red blood cell alloantibodies

BACKGROUND

Erythrocyte alloantibodies are mainly produced after immune stimulation, such as blood transfusion, pregnancy, and transplantation, and are the leading causes of severe hemolytic transfusion reactions and difficulty in blood grouping and matching. Therefore, antibody screening is critical to prevent and improve red cell alloantibodies. Routine tube assay is the primary detection method of antibody screening. Recently, erythrocyte-magnetized technology (EMT) has been increasingly used in clinical practice. This study intends to probe the application and efficacy of the conventional tube and EMT in red blood cell alloantibody titration to provide a reference for clinical blood transfusion.

AIM

To investigate the application value of conventional tube and EMT in red blood cell alloantibody titration and enhance the safety of blood transfusion practice.

METHODS

A total of 1298 blood samples were harvested from blood donors at the Department of Blood Transfusion of our hospital from March 2021 to December 2022. A 5 mL blood sample was collected in tubing, which was then cut, and the whole blood was put into a test tube for centrifugation to separate the serum. Different red blood cell blood group antibody titers were simultaneously detected using the tube polybrene test, tube antiglobulin test (AGT), and EMT screening irregular antibody methods to determine the best test method.

RESULTS

Simultaneous detection was performed through the tube polybrene test, tube AGT and EMT screening irregular antibodies. It was discovered that the EMT screening irregular antibody method could detect all immunoglobulin G (IgG) and immunoglobulin M (IgM) irregular antibodies, and the results of manual tube AGT were satisfactory, but the operation time was lengthy, and the equipment had a large footprint. The EMT screening irregular antibody assay was also conducted to determine its activity against type O Rh (D) red blood cells, and the outcomes were satisfactory. Furthermore, compared to the conventional tube method, the EMT screening irregular antibody method was more cost-effective and had significantly higher detection efficiency.

CONCLUSION

With a higher detection rate, the EMT screening irregular antibody method can detect both IgG and IgM irregular antibodies faster and more effectively than the conventional tube method.

Ultrasononography in Managing Extrapulmonary Tuberculosis: A Randomized, Controlled, Parallel, Superiority, Open-Label Trial

BACKGROUND

Patients with suspected extrapulmonary tuberculosis are often treated empirically. We hypothesized that extended focused assessment with sonography for human immunodeficiency virus (HIV) and tuberculosis (eFASH), in combination with other tests, would increase the proportion of correctly managed patients with suspected extrapulmonary tuberculosis.

METHODS

This trial in adults with suspected extrapulmonary tuberculosis was performed in a rural and an urban hospital in Tanzania. Participants were randomized 1:1 to intervention or routine care, stratified by site and HIV status. All participants underwent clinical evaluation, chest radiography, and testing with sputum Xpert MTB/RIF and urine Xpert MTB/RIF Ultra assays. The intervention was a management algorithm based on results of eFASH plus microbiology, adenosine deaminase (ADA), and chest radiography. The primary outcome was the proportion of correctly managed patients. The presence of positive microbiological or ADA results defined definite tuberculosis. An independent end-point review committee determined diagnoses of probable or no tuberculosis. We evaluated outcomes using logistic regression models, adjusted for randomization stratification factors.

RESULTS

From September 2018 to October 2020, a total of 1036 patients were screened and 701 were randomized (350 to the intervention and 351 to the control group). Of participants in the intervention group, 251 (72%) had a positive eFASH outcome. In 258 (74%) of the intervention and 227 (65%) of the control participants antituberculosis was initiated treatment at baseline. More intervention participants had definite tuberculosis (n = 124 [35%]), compared with controls (n = 85 [24%]). There was no difference between groups for the primary outcome (intervention group, 266 of 286 [93%]; control group, 245 of 266 [92%]; odds ratio, 1.14 [95% confidence interval: .60-2.16]; P = .68). There were no procedure-associated adverse events.

CONCLUSIONS

eFASH did not change the proportion of correctly managed patients but increased the proportion of those with definite tuberculosis.

CLINICAL TRIALS REGISTRATION

Pan African Registry: PACTR201712002829221.

Decision Analytic Modeling for Global Clinical Trial Planning: A Case for HIV-Positive Patients at High Risk for Mycobacterium tuberculosis Sepsis in Uganda

Sepsis is a significant cause of mortality among people living with human immunodeficiency virus (HIV) in sub-Saharan Africa. In the planning period prior to the start of a large multi-country clinical trial studying the efficacy of the immediate empiric addition of anti-tuberculosis therapy to standard-of-care antibiotics for sepsis in people living with HIV, we used decision analysis to assess the costs and potential health outcome impacts of the clinical trial design based on preliminary data and epidemiological parameter estimates. The purpose of this analysis was to highlight this approach as a case example where decision analysis can estimate the cost effectiveness of a proposed clinical trial design. In this case, we estimated the impact of immediate empiric anti-tuberculosis (TB) therapy versus the diagnosis-dependent standard of care using three different TB diagnostics: urine TB-LAM, sputum Xpert-MTB/RIF, and the combination of LAM/Xpert. We constructed decision analytic models comparing the two treatment strategies for each of the three diagnostic approaches. Immediate empiric-therapy demonstrated favorable cost-effectiveness compared with all three diagnosis-dependent standard of care models. In our methodological case exemplar, the proposed randomized clinical trial intervention demonstrated the most favorable outcome within this decision simulation framework. Applying the principles of decision analysis and economic evaluation can have significant impacts on study design and clinical trial planning.

Soft tissue tuberculosis detected by next-generation sequencing: A case report and review of literature

BACKGROUND

Soft tissue tuberculosis is rare and insidious, with most patients presenting with a localized enlarged mass or swelling, which may be factors associated with delayed diagnosis and treatment. In recent years, next-generation sequencing has rapidly evolved and has been successfully applied to numerous areas of basic and clinical research. A literature search revealed that the use of next-generation sequencing in the diagnosis of soft tissue tuberculosis has been rarely reported.

CASE SUMMARY

A 44-year-old man presented with recurrent swelling and ulcers on the left thigh. Magnetic resonance imaging suggested a soft tissue abscess. The lesion was surgically removed and tissue biopsy and culture were performed; however, no organism growth was detected. Finally, Mycobacterium tuberculosis was confirmed as the pathogen responsible for infection through next-generation sequencing analysis of the surgical specimen. The patient received a standardized anti-tuberculosis treatment and showed clinical improvement. We also performed a literature review on soft tissue tuberculosis using studies published in the past 10 years.

CONCLUSION

This case highlights the importance of next-generation sequencing for the early diagnosis of soft tissue tuberculosis, which can provide guidance for clinical treatment and improve prognosis.

Efficacy of Xpert in tuberculosis diagnosis based on various specimens: a systematic review and meta-analysis

Objective

The GeneXpert MTB/RIF assay (Xpert) is a diagnostic tool that has been shown to significantly improve the accuracy of tuberculosis (TB) detection in clinical settings, with advanced sensitivity and specificity. Early detection of TB can be challenging, but Xpert has improved the efficacy of the diagnostic process. Nevertheless, the accuracy of Xpert varies according to different diagnostic specimens and TB infection sites. Therefore, the selection of adequate specimens is critical when using Xpert to identify suspected TB. As such, we have conducted a meta-analysis to evaluate the effectiveness of Xpert for diagnosis of different TB types using several specimens.

Methods

We conducted a comprehensive search of several electronic databases, including PubMed, Embase, the Cochrane Central Register of Controlled Trials, and the World Health Organization clinical trials registry center, covering studies published from Jan 2008 to July 2022. Data were extracted using an adapted version of the Checklist for Critical Appraisal and Data Extraction for Systematic Reviews of Prediction Modeling Studies. Where appropriate, meta-analysis was performed using random-effects models. The risk of bias and level of evidence was assessed using the Quality in Prognosis Studies tool and a modified version of the Grading of Recommendations Assessment, Development, and Evaluation. RStudio was utilized to analyze the results, employing the meta4diag, robvis, and metafor packages.

Results

After excluding duplicates, a total of 2163 studies were identified, and ultimately, 144 studies from 107 articles were included in the meta-analysis based on predetermined inclusion and exclusion criteria. Sensitivity, specificity and diagnostic accuracy were estimated for various specimens and TB types. In the case of pulmonary TB, Xpert using sputum (0.95 95%CI 0.91-0.98) and gastric juice (0.94 95%CI 0.84-0.99) demonstrated similarly high sensitivity, surpassing other specimen types. Additionally, Xpert exhibited high specificity for detecting TB across all specimen types. For bone and joint TB, Xpert, based on both biopsy and joint fluid specimens, demonstrated high accuracy in TB detection. Furthermore, Xpert effectively detected unclassified extrapulmonary TB and tuberculosis lymphadenitis. However, the Xpert accuracy was not satisfactory to distinguish TB meningitis, tuberculous pleuritis and unclassified TB.

Conclusions

Xpert has exhibited satisfactory diagnostic accuracy for most TB infections, but the efficacy of detection may vary depending on the specimens analyzed. Therefore, selecting appropriate specimens for Xpert analysis is essential, as using inadequate specimens can reduce the ability to distinguish TB.

Systematic review registration

https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=370111, identifier CRD42022370111.

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.

Culture filtrate supplementation can be used to improve Mycobacterium tuberculosis culture positivity for spinal tuberculosis diagnosis

Culture remains the gold standard to diagnose spinal tuberculosis (STB) despite the paucibacillary nature of the disease. Current methods can take up to 42 days to yield a result, delaying the ability to rapidly detect drug resistance. Studies have demonstrated the use of supplementation with culture filtrate (CF) from an axenic culture of Mycobacterium tuberculosis (Mtb) as a source of growth factors to improve culture rates. Our objective was to test a modified culture assay, utilizing CF supplemented media (CFSM), to improve culture positivity rates for suspected STB. Twelve patients with suspected STB were assessed by conventional culture (BACTEC™ MGIT 960), GeneXpert™ and standard histopathological examination. Spinal biopsies were taken from areas of diseased vertebral tissue or abscess, predetermined from MRI. Additional biopsies were obtained to assess CFSM for improved detection and faster culture of Mtb. All cases were diagnosed as STB and treated empirically for tuberculosis based on either bacteriological evidence (GeneXpert™, MGIT and/or CFSM positive), or based on clinical presentation. 5 specimens (45.45%) were positive for Mtb DNA as detected by GeneXpert™ and 1 specimen (8.33%) was cultured using MGIT (time to detection; 18 days). CFSM was able to culture 7 specimens (58.3%), with all CFSM positive specimens yielding a culture within 14 days. Two samples were positive only using the CFSM assay pointing to additional yield for diagnostic workup. Modification of standard culture can improve detection of Mtb and reduce time to positivity in individuals with STB where culture material is a requirement.

Diagnostic accuracy of pleural fluid lactate dehydrogenase to adenosine deaminase ratio for tuberculous pleural effusion: an analysis of two cohorts

Background

This study aimed to evaluate the diagnostic accuracy of pleural fluid (PF) lactate dehydrogenase (LDH) to adenosine deaminase (ADA) (LDH/ADA) ratio for tuberculous pleural effusion (TPE). Especially to explore whether the LDH/ADA ratio provides added diagnostic value to ADA.

Methods

The diagnostic accuracy of PF LDH/ADA ratio and ADA for TPE was evaluated in two cohorts, named the BUFF (Biomarkers for patients with Undiagnosed pleural eFFusion) cohort (62 with TPE and 194 with non-TPE) and the SIMPLE (a Study Investigating Markers in PLeural Effusion) cohort (33 with TPE and 177 with non-TPE). Receiver operating characteristic (ROC) curve and decision curve were used to measure the diagnostic accuracy of the PF LDH/ADA ratio. The added diagnostic value of the LDH/ADA ratio to ADA was evaluated with net reclassification improvement (NRI) and integrated discrimination improvement (IDI).

Results

The area under the ROC curves (AUCs) of PF ADA and LDH/ADA ratio in the BUFF cohort were 0.76 and 0.74, respectively. In the SIMPLE cohort, the AUCs of PF ADA and LDH/ADA ratio were 0.80 and 0.85, respectively. The decision curves of PF LDH/ADA and ADA were close in both the BUFF and SIMPLE cohorts. The NRI and IDI analyses did not reveal any added diagnostic value of LDH/ADA to ADA.

Conclusions

PF LDH/ADA ratio has moderate diagnostic accuracy for TPE. It does not provide added diagnostic value beyond ADA. The current evidence does not support LDH/ADA ratio for diagnosing TPE.

Comparison of the frequency and phenotypic profile of Mycobacterium tuberculosis-specific CD4 T cells between the site of disease and blood in pericardial tuberculosis

Studies of the immune response at the site of disease in extra-pulmonary tuberculosis (EPTB) disease are scarce. In this study, we compared the cellular profile of Mycobacterium tuberculosis (Mtb)-specific T cells in pericardial fluid and peripheral blood in patients with pericardial TB (PCTB). Whole blood and pericardial fluid (PCF) samples were collected at the time of diagnostic sampling, with repeat blood sampling after completion of anti-tubercular treatment (ATT) in 16 PCTB patients, most of them being HIV-1 infected (n=14). These samples were stimulated ex vivo and the phenotypic and functional cellular profile of PCF and blood was assessed by flow cytometry. We found that lymphocytes were the predominant cell type in PCF in PCTB, with a preferential influx of CD4 T cells. The frequencies of TNF-α producing Mtb-specific granulocytes and Mtb-specific CD4 T cells were significantly higher in PCF compared to blood. Mtb-specific CD4 T cells in PCF exhibited a distinct phenotype compared to those in blood, with greater GrB expression and lower CD27 and KLRG1 expression. We observed no difference in the production IFNγ, TNF or IL-2 by Mtb-specific CD4 T cells between the two compartments, but MIP-1β production was lower in the PCF T cells. Bacterial loads were not associated with alterations in the phenotype or function of Mtb-specific CD4 T cells. Upon ATT completion, HLA-DR, Ki-67 and GrB expression was significantly decreased, and relative IL-2 production was increased in peripheral Mtb-specific CD4 T cells. Overall, using an ex vivo assay to compare the immune response towards Mtb in PCF and in blood, we identified significant difference in the phenotypic profile of Mtb-specific CD4 T response between these two compartments. Moreover, we show that the activation profile of peripheral Mtb-specific CD4 T cells could be used to monitor treatment response in PCTB.

Mass Spectrometry-Based Proteomic and Metabolomic Profiling of Serum Samples for Discovery and Validation of Tuberculosis Diagnostic Biomarker Signature

Tuberculosis (TB) is a transmissible disease listed as one of the 10 leading causes of death worldwide (10 million infected in 2019). A swift and precise diagnosis is essential to forestall its transmission, for which the discovery of effective diagnostic biomarkers is crucial. In this study, we aimed to discover molecular biomarkers for the early diagnosis of tuberculosis. Two independent cohorts comprising 29 and 34 subjects were assayed by proteomics, and 49 were included for metabolomic analysis. All subjects were arranged into three experimental groups—healthy controls (controls), latent TB infection (LTBI), and TB patients. LC-MS/MS blood serum protein and metabolite levels were submitted to univariate, multivariate, and ROC analysis. From the 149 proteins quantified in the discovery set, 25 were found to be differentially abundant between controls and TB patients. The AUC, specificity, and sensitivity, determined by ROC statistical analysis of the model composed of four of these proteins considering both proteomic sets, were 0.96, 93%, and 91%, respectively. The five metabolites (9-methyluric acid, indole-3-lactic acid, trans-3-indoleacrylic acid, hexanoylglycine, and N-acetyl-L-leucine) that better discriminate the control and TB patient groups (VIP > 1.75) from a total of 92 metabolites quantified in both ionization modes were submitted to ROC analysis. An AUC = 1 was determined, with all samples being correctly assigned to the respective experimental group. An integrated ROC analysis enrolling one protein and four metabolites was also performed for the common control and TB patients in the proteomic and metabolomic groups. This combined signature correctly assigned the 12 controls and 12 patients used only for prediction (AUC = 1, specificity = 100%, and sensitivity = 100%). This multiomics approach revealed a biomarker signature for tuberculosis diagnosis that could be potentially used for developing a point-of-care diagnosis clinical test.

Female Genital Tuberculosis

Female genital tuberculosis (FGTB) is an important cause of morbidity and infertility worldwide. Mycobacterium tuberculosis most commonly spreads to the genital tract from a focus elsewhere in the body and affects the bilateral fallopian tubes and/or endometrium. Many patients with FGTB have indolent disease and are only diagnosed after evaluation for infertility. Women may present with menstrual irregularities, lower abdominal or pelvic pain, or abnormal vaginal discharge. Given the low sensitivity of diagnostic tests, various composite reference standards are used to diagnose FGTB, including some combination of endoscopic findings, microbiological or molecular testing, and histopathological evidence in gynecological specimens. Early treatment with a standard regimen of a 2-month intensive phase with isoniazid, rifampin, ethambutol, and pyrazinamide, followed by a 4-month continuation phase with isoniazid and rifampin, is recommended to prevent irreversible organ damage. However, even with treatment, FGTB can lead to infertility or pregnancy-related complications, and stigma is pervasive.

Diagnostic biomarkers for active tuberculosis: progress and challenges

Tuberculosis (TB) is a leading cause of morbidity and mortality from a single infectious agent, despite being preventable and curable. Early and accurate diagnosis of active TB is critical to both enhance patient care, improve patient outcomes, and break Mycobacterium tuberculosis (Mtb) transmission cycles. In 2020 an estimated 9.9 million people fell ill from Mtb, but only a little over half (5.8 million) received an active TB diagnosis and treatment. The World Health Organization has proposed target product profiles for biomarker- or biosignature-based diagnostics using point-of-care tests from easily accessible specimens such as urine or blood. Here we review and summarize progress made in the development of pathogen- and host-based biomarkers for active TB diagnosis. We describe several unique patient populations that have posed challenges to development of a universal diagnostic TB biomarker, such as people living with HIV, extrapulmonary TB, and children. We also review additional limitations to widespread validation and utilization of published biomarkers. We conclude with proposed solutions to enhance TB diagnostic biomarker validation and uptake.

Diagnostic accuracy of different bronchoscopic specimens in sputum Xpert MBT/RIF- negative pulmonary TB patients

Background

Tuberculosis (TB) control remains a critical public health problem worldwide. Rapid diagnosis and proper treatment are beneficial for the effective control of tuberculosis transmission. Diagnostic challenges arise when a patient has a clinical and radiological suspicion of tuberculosis but cannot produce sputum, sputum acid-fast bacilli, or Xpert Mycobacterium tuberculosis/rifampicin (Xpert MTB/RIF) is negative, resulting in suboptimal management. As a result, more invasive techniques must be used on these patients to establish the diagnosis.

Methods

A retrospective study recruited 330 suspected pulmonary TB patients with negative sputum of Xpert MBT/RIF who underwent bronchoscopy between March 2018 and December 2021. The diagnostic yields of bronchoalveolar lavage fluid (acid-fast bacilli, Xpert MTB/RIF, and culture) and histopathologic examination (HPE) were calculated and compared to the final diagnosis and culture as a gold standard.

Results

Out of 330 suspected pulmonary TB patients, 181 had a final diagnosis of TB, and 149 had non-TB. The sensitivity of BALF (culture, Xpert, acid-fast bacilli) and trans-bronchial lung biopsy (HPE) was 80.7%, 72.9%, 21.1%, and 87.1%, respectively. Multiple nodules were associated with significantly higher BALF Xpert MTB, bronchoalveolar lavage fluid culture, and trans-bronchial lung biopsy (HPE) positivity.

Conclusions

Bronchoscopic specimens are essential for accurate and rapid diagnosis of sputum Xpert MBT/RIF negative patients with high clinical and radiological suspicion of tuberculosis.

Comparison of tests done, and tuberculosis cases detected by Xpert® MTB/RIF and Xpert® MTB/RIF-Ultra in Uganda

Background

Uganda introduced Xpert® MTB/RIF assay into its TB diagnostic algorithm in January 2012. In July 2018, this assay was replaced with Xpert® MTB/RIF Ultra assay. We set out to compare the tests done and tuberculosis cases detected by Xpert® MTB/RIF and Xpert® MTB/RIF Ultra assay in Uganda.

Methods

This was a before and after study, with the tests done and TB cases detected between Jan-June 2019 when using Xpert® MTB/RIF Ultra assay compared to those done between Jan-June 2018 while using Xpert® MTB/RIF assay. This data was analyzed using Stata version 13, it was summarized into measures of central tendency and the comparison between Xpert® MTB/RIF Ultra and Xpert® MTB/RIF was explored using a two-sided T-test which was considered significant if p <0.05.

Results

One hundred and twelve (112) GeneXpert sites out of a possible 239 were included in the study. 128,476 (M: 1147.11, SD: 842.88) tests were performed with Xpert® MTB/RIF Ultra assay, with 9693 drug-susceptible TB (DS-TB) cases detected (M: 86.54, SD: 62.12) and 144 (M: 1.28, SD: 3.42) Rifampicin Resistant TB cases (RR-TB). Whilst 107, 890 (M: 963.30, SD: 842.88) tests were performed with Xpert® MTB/RIF assay between, 8807 (M: 78.63, SD: 53.29) DS-TB cases were detected, and 147 (M: 1.31, SD: 2.39) RR-TB cases. The Number Need to Test (NNT) to get one TB case was 12 for Xpert® MTB/RIF and 13 for Xpert ®MTB/RIF Ultra. On comparing the two assays in terms of test performance (p = 0.75) and case detection both susceptible TB (p = 0.31) and RR-TB (p = 0.95) were not found statistically significant.

Conclusions

This study found no significant difference in test performance and overall detection of DS-TB and RR-TB when using Xpert® MTB/RIF Ultra and Xpert® MTB/RIF assays. The health systems approach should be used to elucidate all the probable potential of Xpert® MTB/RIF Ultra.

Diagnostic performance of adenosine deaminase for abdominal tuberculosis: A systematic review and meta-analysis

Background and aim

Abdominal tuberculosis (TB) is a common type of extrapulmonary TB with an insidious onset and non-specific symptoms. Adenosine deaminase (ADA) levels increase rapidly in the early stages of abdominal TB. However, it remains unclear whether ADA serves as a diagnostic marker for abdominal TB.

Methods

We performed a systematic literature search for relevant articles published in PubMed, Web of Science, Cochrane Library, and Embase up to April 2022. First, we used the Quality Assessment of Diagnostic Accuracy Studies tool-2 (QUADAS-2), to evaluate the quality of the included articles. Bivariate and hierarchical summary receiver operating characteristic (HSROC) models were then utilized to analyze pooled sensitivity, specificity, positive likelihood ratio (PLR), negative likelihood ratio (NLR), diagnostic odds ratio (DOR) and area under the receiver operating characteristic curve (AUROC). In addition, we explored a subgroup analysis for potential heterogeneity and publication bias among the included literature.

Results

Twenty-four articles (3,044 participants, 3,044 samples) which met the eligibility criteria were included in this study. The pooled sensitivity and specificity of ADA for abdominal TB detection were 93% [95% confidence interval (CI): 0.89-0.95] and 95% (95% CI: 0.93-0.96), respectively. PLR and NLR were 18.6 (95% CI: 14.0-24.6) and 0.08 (95% CI: 0.05-0.12), respectively. DOR and AUROC were 236 (95% CI: 134-415) and 0.98 (95% CI: 0.96-0.99), respectively. Furthermore, no heterogeneity or publication bias was found.

Conclusions

Our meta-analysis found ADA to be of excellent diagnostic value for abdominal TB and could be used as an auxiliary diagnostic tool.

Systematic review registration

https://www.crd.york.ac.uk/prospero/, identifier: CRD42022297931.

Global trends of research on tuberculous pleurisy over the past 15 years: A bibliometric analysis

Tuberculous pleurisy (TP) is a common type of extrapulmonary tuberculosis (EPTB). With the development of research and changes in TP patient characteristics, an increasing number of studies have revealed the prevalence, risk factors, and novel diagnosis techniques. Thus, this bibliometric analysis was performed to identify global scientific output characteristics and research hotspots and frontiers for TP over the past 15 years. We searched the Web of Science Core Collection (WoSCC) Science Citation Index Expanded (SCI-expanded) for literature published between 2007 and 2021 and recorded their information. The Bibliometrix software package was used for bibliometric indicator analysis, and VOSviewer was used to visualize the trends of and hotspots in TP research. A total of 1,464 original articles were reviewed, and the results indicated that the annual number of publications (Np) focusing on TP has increased over the past 15 years. China had the largest number of papers and the highest H-index, and the United States ranked first for number of citations (Nc). EGYPTIAN KNOWLEDGE BANK and PLOS ONE were the most prolific unit and journal, respectively. The use of the Xpert assay and immune-related biomarker detection to diagnose TP appears to be a recent research hotspot. This bibliometric study demonstrated that the number of publications related to TP have tended to increase. China is a major producer, and the United States is an influential country in this field. Research in the past 15 years has been predominantly clinical research. The diagnosis of TP was the focus of research, and the exploration of novel diagnostic techniques, verification of diagnostic markers, and combination of diagnostic methods have been recent research hotspots. Immune-related biomarkers should be given more attention in the field of TP diagnosis.

Gaps and Interventions across the Diagnostic Care Cascade of TB Patients at the Level of Patient, Community and Health System: A Qualitative Review of the Literature

Tuberculosis (TB) continues to be one of the important public health concerns globally, and India is among the seven countries with the largest burden of TB. There has been a consistent increase in the notifications of TB cases across the globe. However, the 2018 estimates envisage a gap of about 30% between the incident and notified cases of TB, indicating a significant number of patients who remain undiagnosed or ‘missed’. It is important to understand who is ‘missed’, find this population, and provide quality care. Given these complexities, we reviewed the diagnostic gaps in the care cascade for TB. We searched Medline via PubMed and CENTRAL databases via the Cochrane Library. The search strategy for PubMed was tailored to individual databases and was as: ((((((tuberculosis[Title/Abstract]) OR (TB[Title/Abstract])) OR (koch *[Title/Abstract])) OR (“tuberculosis”[MeSH Terms]))) AND (((diagnos *) AND (“diagnosis”[MeSH Terms])))). Furthermore, we screened the references list of the potentially relevant studies to seek additional studies. Studies retrieved from these electronic searches and relevant references included in the bibliography of those studies were reviewed. Original studies in English that assessed the causes of diagnostic gaps and interventions used to address them were included. Delays in diagnosis were found to be attributable to both the individuals’ and the health system’s capacity to diagnose and promptly commence treatment. This review provides insights into the diagnostic gaps in a cascade of care for TB and different interventions adopted in studies to close this gap. The major diagnostic gaps identified in this review are as follows: people may not have access to TB diagnostic tests, individuals are at a higher risk of missed diagnosis, services are available but people may not seek care with a diagnostic facility, and patients are not diagnosed despite reaching health facilities. Therefore, reaching the goal to End TB requires putting in place models and methods to provide prompt and quality assured diagnosis to populations at par.

Insight into diagnosis of pleural tuberculosis with special focus on nucleic acid amplification tests

INTRODUCTION

Pleural tuberculosis (TB) is the archetype of extrapulmonary TB (EPTB), which mainly affects the pleural space and leads to exudative pleural effusion. Diagnosis of pleural TB is a difficult task predominantly due to atypical clinical presentations and sparse bacillary load in clinical specimens.

AREA COVERED

We reviewed the current literature on the globally existing conventional/latest modalities for diagnosing pleural TB. Bacteriological examination (smear/culture), tuberculin skin testing/interferon-γ release assays, biochemical testing, imaging and histopathological/cytological examination are the main modalities. Moreover, nucleic acid amplification tests (NAATs), i.e. loop-mediated isothermal amplification, PCR/multiplex-PCR, nested-PCR, real-time PCR and GeneXpert® MTB/RIF are being utilized. Currently, GeneXpert Ultra, Truenat MTB^TM, detection of circulating Mycobacterium tuberculosis (Mtb) cell-free DNA by NAATs, aptamer-linked immobilized sorbent assay and immuno-PCR (I-PCR) have also been exploited.

EXPERT OPINION

Routine tests are not adequate for effective pleural TB diagnosis. The latest molecular/immunological tests as discussed above, and the other tools, i.e. real-time I-PCR/nanoparticle-based I-PCR and identification of Mtb biomarkers within urinary/serum extracellular vesicles being utilized for pulmonary TB and other EPTB types may also be exploited to diagnose pleural TB. Reliable diagnosis and early therapy would reduce the serious complications associated with pleural TB, i.e. TB empyema, pleural fibrosis, etc.

Bayesian latent class analysis produced diagnostic accuracy estimates that were more interpretable than composite reference standards for extrapulmonary tuberculosis tests

BACKGROUND

Evaluating the accuracy of extrapulmonary tuberculosis (TB) tests is challenging due to lack of a gold standard. Latent class analysis (LCA), a statistical modeling approach, can adjust for reference tests' imperfect accuracies to produce less biased test accuracy estimates than those produced by commonly used methods like composite reference standards (CRSs). Our objective is to illustrate how Bayesian LCA can address the problem of an unavailable gold standard and demonstrate how it compares to using CRSs for extrapulmonary TB tests.

METHODS

We re-analyzed a dataset of presumptive extrapulmonary TB cases in New Delhi, India, for three forms of extrapulmonary TB. Results were available for culture, smear microscopy, Xpert MTB/RIF, and a non-microbiological test, cytopathology/histopathology, or adenosine deaminase (ADA). A diagram was used to define assumed relationships between observed tests and underlying latent variables in the Bayesian LCA with input from an inter-disciplinary team. We compared the results to estimates obtained from a sequence of CRSs defined by increasing numbers of positive reference tests necessary for positive disease status.

RESULTS

Data were available from 298, 388, and 230 individuals with presumptive TB lymphadenitis, meningitis, and pleuritis, respectively. Using Bayesian LCA, estimates were obtained for accuracy of all tests and for extrapulmonary TB prevalence. Xpert sensitivity neared that of culture for TB lymphadenitis and meningitis but was lower for TB pleuritis, and specificities of all microbiological tests approached 100%. Non-microbiological tests' sensitivities were high, but specificities were only moderate, preventing disease rule-in. CRSs' only provided estimates of Xpert and these varied widely per CRS definition. Accuracy of the CRSs also varied by definition, and no CRS was 100% accurate.

CONCLUSION

Unlike CRSs, Bayesian LCA takes into account known information about test performance resulting in accuracy estimates that are easier to interpret. LCA should receive greater consideration for evaluating extrapulmonary TB diagnostic tests.

The value of histological examination in the diagnosis of tuberculous lymphadenitis in the era of rapid molecular diagnosis

Extrapulmonary tuberculosis often poses a diagnostic challenge. This study aimed to assess the value of histological examination in diagnosing tuberculous lymphadenitis (LNTB) when performed simultaneously with rapid molecular assay (Xpert MTB/RIF) testing. People presumed to have LNTB were prospectively enrolled in a tertiary care hospital. Excision biopsy was performed and tested by histology, Xpert, and culture. Of 390 lymph nodes, 11 (2.8%) were positive by AFB microscopy, 124 (31.8%) by Xpert, 137 (35.1%) by culture, and histopathology was consistent with TB in 208 (53.3%). Altogether, LNTB was diagnosed in 228 and bacteriologically confirmed TB in 178 cases. Against culture, histopathology versus Xpert had higher sensitivity (93 vs. 62%) but lower specificity (68 vs. 83%). In patients with short clinical history, a significantly higher number of Xpert-positive specimens were culture-positive. Among patients with histology suggestive of TB, no difference was seen in response to treatment between bacteriology positive and negative, but a significant slow response was noted in bacteriology confirmed TB with nonspecific histology. In a country like Pakistan, with high TB and low HIV prevalence, diagnosis is possible for more than 95% of LNTB when Xpert and histopathology examination is used in combination, compared to less than 60% by Xpert alone.

Reimagining the status quo: How close are we to rapid sputum-free tuberculosis diagnostics for all?

Rapid, accurate, sputum-free tests for tuberculosis (TB) triage and confirmation are urgently needed to close the widening diagnostic gap. We summarise key technologies and review programmatic, systems, and resource issues that could affect the impact of diagnostics. Mid-to-early-stage technologies like artificial intelligence-based automated digital chest X-radiography and capillary blood point-of-care assays are particularly promising. Pitfalls in the diagnostic pipeline, included a lack of community-based tools. We outline how these technologies may complement one another within the context of the TB care cascade, help overturn current paradigms (eg, reducing syndromic triage reliance, permitting subclinical TB to be diagnosed), and expand options for extra-pulmonary TB. We review challenges such as the difficulty of detecting paucibacillary TB and the limitations of current reference standards, and discuss how researchers and developers can better design and evaluate assays to optimise programmatic uptake. Finally, we outline how leveraging the urgency and innovation applied to COVID-19 is critical to improving TB patients' diagnostic quality-of-care.

Abdominal Tuberculosis Mimicking Ovarian Cancer: A Case Report and Review of the Literature

Introduction

Tuberculosis (TB) is a disease with high morbidity and mortality resulting from infection by Mycobacterium tuberculosis. TB can disseminate to any organ system of the body resulting in extrapulmonary tuberculosis. Interestingly, CA-125, which is a biomarker for some cancer, also rises in benign diseases such as pulmonary and extrapulmonary tuberculosis which may complicate diagnosis. In this case report, we present an abdominal tuberculosis patient that was initially presented as ovarian cancer.

Case Report

A 30-year-old woman admitted to the emergency department with chief complaint of fatigue and shortness of breath since 3 months ago. She had lost around 20 kg weight in the past 5 months. She was previously suspected with ovarian cancer because of the characteristic features of malignancy, high levels of CA-125, and positive PET scan. She was later diagnosed with abdominal TB. Subsequently, the patient was given anti-TB drugs, and the patient showed clinical improvement.

Conclusion

In the case of an elevated CA-125, clinicians should consider extrapulmonary TB as a differential diagnosis of ovarian cancer, especially in countries with high burden of tuberculosis.

Establishment and evaluation of an overlap extension polymerase chain reaction technique for rapid and efficient detection of drug-resistance in Mycobacterium tuberculosis

BACKGROUND

Rapid and accurate detection of drug resistance in Mycobacterium tuberculosis is critical for effective control of tuberculosis (TB). Herein, we established a novel, low cost strategy having high accuracy and speed for the detection of M. tuberculosis drug resistance, using gene splicing by overlap extension PCR (SOE PCR).

METHODS

The SOE PCR assay and Sanger sequencing are designed and constructed to detect mutations of rpoB, embB, katG, and inhA promoter, which have been considered as the major contributors to rifampicin (RFP), isoniazid (INH), and ethambutol (EMB) resistance in M. tuberculosis. One hundred and eight M. tuberculosis isolates came from mycobacterial cultures of TB cases at Chongqing Public Health Medical Center in China from December 2018 to April 2019, of which 56 isolates were tested with the GeneXpert MTB/RIF assay. Performance evaluation of the SOE PCR technique was compared with traditional mycobacterial culture and drug susceptibility testing (DST) or GeneXpert MTB/RIF among these isolates. Kappa identity test was used to analyze the consistency of the different diagnostic methods.

RESULTS

We found that the mutations of S531L, S315T and M306V were most prevalent for RFP, INH and EMB resistance, respectively, in the 108 M. tuberculosis isolates. Compared with phenotypic DST, the sensitivity and specificity of the SOE PCR assay for resistance detection were 100.00% and 88.00% for RFP, 94.64% and 94.23% for INH, and 68.97% and 79.75% for EMB, respectively. Compared with the GeneXpert MTB/RIF, the SOE PCR method was completely consistent with results of the GeneXpert MTB/RIF, with a concordance of 100% for resistance to RFP.

CONCLUSIONS

In present study, a novel SOE PCR diagnostic method was successfully developed for the accurate detection of M. tuberculosis drug resistance. Our results using this method have a high consistency with that of traditional phenotypic DST or GeneXpert MTB/RIF, and SOE PCR testing in clinical isolates can also be conducted rapidly and simultaneously for detection of drug resistance to RFP, EMB, and INH.

Pleural Fluid Soluble Interleukin-2 Receptor as a Biomarker for the Diagnosis of Tuberculosis Pleural Effusion: A Systematic Review and Meta-Analysis

Background

Several studies have assessed the diagnostic accuracy of pleural fluid soluble interleukin-2 receptor (sIL-2R) for tuberculous pleural effusion (TPE) but with varied results. Therefore, we conducted this systematic review and meta-analysis to evaluate the accuracy of sIL-2R for TPE.

Methods

PubMed, Ovid, and Web of Science databases were searched from inception to 23 March 2021 to identify eligible studies concerning the diagnostic accuracy of fluid sIL-2R for TPE. The sensitivity and specificity of sIL-2R for TPE were pooled with a bivariate model. We estimated the global diagnostic accuracy of PE sIL-2R with a summary receiver operating characteristic (sROC) curve. The revised Quality Assessment for Diagnostic Accuracy Studies tool (QUADAS-2) was used to assess the quality of eligible studies.

Results

A total of nine studies with 270 TPEs and 586 non-TPEs were included in the final analysis. The pooled sensitivity and specificity were 0.81 (95% CI: 0.76–0.86) and 0.92 (95% CI: 0.77–0.98), respectively. The area under the sROC curve (AUC) was 0.82 (95% CI: 0.79–0.86). No significant publication bias was observed.

Conclusions

Pleural fluid sIL-2R is a useful diagnostic marker for TPE. However, the diagnostic accuracies of already available biomarkers such as pleural fluid adenosine deaminase, interferon-γ, and interleukin-27 appear to be superior relative to sIL-2R. Therefore, it might not be preferable to use sIL-2R for diagnosing TPE.

HIV-Negative Rifampicin Resistance/Multidrug-Resistant Extrapulmonary Tuberculosis in China from 2015 to 2019: A Clinical Retrospective Investigation Study from a National Tuberculosis Clinical Research Center

Background

China is the region with a high global burden of rifampicin resistance/multidrug-resistant tuberculosis (RR/MDR-TB) and low HIV incidence. Our aim was to assess the clinical and demographic characteristics of RR/MDR-extrapulmonary tuberculosis (EPTB) from 2015 to 2019 to provide evidence for the prevention and control of the disease in high TB burden areas.

Methods

We investigated the clinical and demographic data of all MDR/RR-EPTB cases in a TB specialized hospital from China and compared the cases with the MDR/RR-pulmonary tuberculosis (PTB) patients over the same period.

Results

Of the RR/MDR-TB patients enrolled, 15.4 were EPTB. The most common anatomical site was pleural/chest wall (25.9%). Compared with RR/MDR-PTB, females were more likely to be susceptible to RR/MDR-EPTB (OR 1.65, 95% CI 1.52–1.77); the risk of RR/MDR-EPTB for 25–44 years group increased (OR 1.61, 95% CI 1.52–1.77), and then decreased with the increasing age (OR 1.48, 95% CI 0.74–1.69 for 44–65 years group and OR 2.23, 95% CI 0.98–2.71 for ≥65 years group); more likely to be newly diagnosed (p < 0.01) and less likely to to combine with diabetes (P < 0.01), more dependent on GeneXpert MTB/RIF (Xpert, 90.9%) for diagnosis, with significantly higher rates of pre-XDR/XDR and significantly lower favorable treatment outcomes (both p < 0.01).

Conclusion

There are clinical and demographic differences between RR/MDR-PTB and RR/MDR-PTB. Xper should be recommended at an early stage for suspected patients, and fluoroquinolones should be used cautiously for anti-infective therapy in this population.

The Role of Core Needle Biopsy Pathology Combined with Molecular Tests in the Diagnosis of Lymph Node Tuberculosis

Background

Early lymph node tuberculosis (LNTB) diagnosis is still difficult. The majority of LN specimens require the undertaking of invasive and unpleasant procedures.

Purpose

To evaluate the diagnostic efficacy of pathology when combined with molecular tests for the diagnosis of LNTB in core needle biopsy (CNB) specimens and to compare that diagnostic efficacy with that deriving from tissue specimens’ examination alone.

Methods

We retrospectively analyzed the medical records of LNTB patients who met the inclusion criteria. The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and area under the curve (AUC) of pathology, molecular tests, and parallel test (positive result for either of these two assays) were calculated to evaluate their diagnostic efficacy compared with a composite reference standard.

Results

A total of 289 patients were included in the study. The overall sensitivity, specificity, PPV, NPV, and AUC of pathology, molecular tests, and parallel test were 94.5%, 97.2%, 99.6%, 71.4%, 0.96; 73.1%, 100.0%, 100.0%, 34.6%, 0.87; and 98.4%, 97.2%, 99.6%, 89.7%, 0.98, respectively. For CNB specimens, these values for pathology, molecular tests, and parallel test were 93.3%, 96.2%, 99.4%, 69.4%, 0.95; 76.4%, 100.0%, 100.0%, 40.0%, 0.88; and 99.4%, 96.2%, 99.4%,96.2%,0.98, while those same values for the tissue were 96.6%, 100.0%, 100.0%, 76.9%, 0.98; 67.1%, 100.0%, 100.0%, 25.6%, 0.84; and 96.6%, 100.0%, 100.0%, 76.9%,0.98, respectively.

Conclusion

The validity of pathology and molecular testing when using CNB specimens was similar to that of tissue specimens for relevant assessment approaches. For the LNTB diagnosis, CNB specimens were preferred for the simultaneous undertaking of pathological examination and molecular testing.

Diagnostic Model for Discrimination Between Tuberculous Meningitis and Bacterial Meningitis

Background

The differential diagnosis between tuberculous meningitis (TBM) and bacterial meningitis (BM) remains challenging in clinical practice. This study aimed to establish a diagnostic model that could accurately distinguish TBM from BM.

Methods

Patients with TBM or BM were recruited between January 2017 and January 2021 at Tongji Hospital (Qiaokou cohort) and Sino-French New City Hospital (Caidian cohort). The detection for indicators involved in cerebrospinal fluid (CSF) and T-SPOT assay were performed simultaneously. Multivariate logistic regression was used to create a diagnostic model.

Results

A total of 174 patients (76 TBM and 98 BM) and another 105 cases (39 TBM and 66 BM) were enrolled from Qiaokou cohort and Caidian cohort, respectively. Significantly higher level of CSF lymphocyte proportion while significantly lower levels of CSF chlorine, nucleated cell count, and neutrophil proportion were observed in TBM group when comparing with those in BM group. However, receiver operating characteristic (ROC) curve analysis showed that the areas under the ROC curve (AUCs) produced by these indicators were all under 0.8. Meanwhile, tuberculosis-specific antigen/phytohemagglutinin (TBAg/PHA) ratio yielded an AUC of 0.889 (95% CI, 0.840–0.938) in distinguishing TBM from BM, with a sensitivity of 68.42% (95% CI, 57.30%–77.77%) and a specificity of 92.86% (95% CI, 85.98%–96.50%) when a cutoff value of 0.163 was used. Consequently, we successfully established a diagnostic model based on the combination of TBAg/PHA ratio, CSF chlorine, CSF nucleated cell count, and CSF lymphocyte proportion for discrimination between TBM and BM. The established model showed good performance in differentiating TBM from BM (AUC: 0.949; 95% CI, 0.921–0.978), with 81.58% (95% CI, 71.42%–88.70%) sensitivity and 91.84% (95% CI, 84.71%–95.81%) specificity. The performance of the diagnostic model obtained in Qiaokou cohort was further validated in Caidian cohort. The diagnostic model in Caidian cohort produced an AUC of 0.923 (95% CI, 0.867–0.980) with 79.49% (95% CI, 64.47%–89.22%) sensitivity and 90.91% (95% CI, 81.55%–95.77%) specificity.

Conclusions

The diagnostic model established based on the combination of four indicators had excellent utility in the discrimination between TBM and BM.

SARS-CoV-2 Supply Shortages and Tuberculosis Diagnostics: Current Issues Requiring Immediate Solutions

The SARS-CoV-2 pandemic has strained manufacturing capacity worldwide, resulting in significant shortages of laboratory supplies both directly and indirectly. Such shortages include probe-based kits for detection of the Mycobacterium tuberculosis complex from positive liquid broth cultures. These shortages and possible loss of this particular assay have consequences for laboratory testing algorithms and public health in the United States. As there are no FDA-approved, commercially available options that currently exist which could immediately fill this gap, laboratories must identify alternatives and plan for modifying current testing algorithms to accommodate this change.