A retrospective study on Xpert MTB/RIF for detection of tuberculosis in a teaching hospital in China

Performance of Xpert MTB/RIF and sputum microscopy compared to sputum culture for diagnosis of tuberculosis in seven hospitals in Indonesia

Introduction

Tuberculosis (TB) is a major public health concern in Indonesia, where the incidence was 301 cases per 100,000 inhabitants in 2020 and the prevalence of multi-drug resistant (MDR) TB is increasing. Diagnostic testing approaches vary across Indonesia due to resource limitations. Acid-fast bacilli (AFB) smear is widely used, though Xpert MTB/RIF has been the preferred assay for detecting TB and rifampicin resistance since 2012 due to higher sensitivity and ability to rapidly identify rifampicin resistance. However, <1,000 Xpert instruments were available in Indonesia as of 2020 and the Xpert supply chain has suffered interruptions.

Methods

We compared the performance of Xpert MTB/RIF and AFB smear to facilitate optimization of TB case identification. We analyzed baseline data from a cohort study of adults with pulmonary TB conducted at seven hospitals across Indonesia. We evaluated sensitivity and specificity of AFB smear and Xpert MTB/RIF using Mycobacterium tuberculosis (Mtb) culture as the gold standard, factors associated with assay results, and consistency of Xpert MTB/RIF with drug susceptibility test (DST) in detecting rifampicin resistance.

Results

Sensitivity of AFB smear was significantly lower than Xpert MTB/RIF (86.2 vs. 97.4%, p-value <0.001), but specificity was significantly better (86.7 vs. 73.3%, p-value <0.001). Performance varied by hospital. Positivity rate for AFB smear and Mtb culture was higher in subjects with pulmonary cavities and in morning sputum samples. Consistency of Xpert MTB/RIF with DST was lower in those with rifampicin- sensitive TB by DST.

Discussion

Additional evaluation using sputa from primary and secondary Indonesian health centers will increase the generalizability of the assessment of AFB smear and Xpert MTB/RIF performance, and better inform health policy.

Clinical trial registration

[https://clinicaltrials.gov/], identifier [NCT027 58236].

Adenosine deaminase-based measurement in the differential diagnosis of pleural effusion: a multicenter retrospective study

INTRODUCTION

The differential diagnosis of pleural effusion is difficult, and studies have reported on the potential role of adenosine deaminase (ADA) in the differential diagnosis of undiagnosed pleural effusion. This retrospective study aimed to investigate the diagnostic role of ADA in pleural effusion.

METHODS

266 patients with pleural effusion from three centers were enrolled. The concentrations of ADA and lactate dehydrogenase (LDH) were measured in pleural fluids and serum samples of the patients. The diagnostic performance of ADA-based measurement for tuberculous pleural effusion (TPE), malignant pleural effusion (MPE), and parapneumonic effusion (PPE) was examined by receiver operating characteristic (ROC) curve analysis.

RESULTS

An area under the ROC curve (AUC) value of 0.909 was obtained using the pleural ADA values as the indicator for TPE identification (sensitivity: 87.50%, specificity: 87.82%). The ratio of serum LDH to pleural ADA (cancer ratio) provided the predictive capacity with an AUC of 0.879 for MPE diagnosis (sensitivity: 95.04%, specificity: 67.06%). At a cut-off value of 14.29, the pleural ADA/LDH ratio showed a sensitivity and specificity of 81.13% and 83.67%, respectively, and a high AUC value of 0.888 for the differential diagnosis of PPE from TPE.

CONCLUSION

ADA-based measurement is helpful for the differential diagnosis of pleural effusion. Further studies should be performed to validate these results.

Diagnosis of extrapulmonary tuberculosis by ultrasound-guided biopsy: A retrospective comparison study

Objective

To compare the diagnostic performance of laboratory assays on the ultrasound-guided core needle biopsy samples for diagnosis of extra-pulmonary tuberculosis (EPTB) in HIV-positive and HIV-negative patients.

Methods

A total of 217 patients suspected to have EPTB underwent lesion biopsy from 2017 to 2020. Results of laboratory tests on the biopsy and non-biopsy samples were collected with clinical data for retrospective analysis of test utility. The calculated diagnostic accuracy of the tests was stratified according to the specimen types and HIV status.

Results

The cohort contained 118 patients with a final positive diagnosis of extrapulmonary tuberculosis (EPTB group, 54.4%) and 99 finally diagnosed as without TB (non-EPTB group, 45.6%). The risk factor for EPTB was HIV co-infection (OR 2.22, 95% CI 1.17-4.28, p = 0.014). In biopsy samples, GeneXpert (Xpert) showed higher sensitivity (96.6% [91.6-98.7], p < 0.0001) than culture (56.1% [47.0-64.9]). Regardless of HIV status, Xpert had the highest sensitivity (>95%) and specificity (nearly 100%) of any methods. In non-biopsy samples, only T-SPOT.TB (T-SPOT) showed higher sensitivity than culture (90.9% [62.3-99.5] vs 35.3% [17.3-58.7], p = 0.0037). Furthermore, the sensitivities of Xpert were lower in non-biopsy samples (60.0% [23.1-92.9], p = 0.022) than in biopsy samples (100% [86.7-100]). Even in smear-negative biopsy samples, Xpert still had higher sensitivity than culture and retained high specificity (100% [95.7-100]).

Conclusion

Superior performance of Xpert in diagnosing EPTB was observed regardless of HIV status and specimen types. Nevertheless, the biopsy samples still substantially facilitated the accurate diagnosis of extrapulmonary tuberculosis.

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.

The performance of detecting Mycobacterium tuberculosis complex in lung biopsy tissue by metagenomic next-generation sequencing

Background

Tuberculosis (TB) is a chronic infectious disease caused by the Mycobacterium tuberculosis complex (MTBC), which is the leading cause of death from infectious diseases. The rapid and accurate microbiological detection of the MTBC is crucial for the diagnosis and treatment of TB. Metagenomic next-generation sequencing (mNGS) has been shown to be a promising and satisfying application of detection in infectious diseases. However, relevant research about the difference in MTBC detection by mNGS between bronchoalveolar lavage fluid (BALF) and lung biopsy tissue specimens remains scarce.

Methods

We used mNGS to detect pathogens in BALF and lung biopsy tissue obtained by CT-guide percutaneous lung puncture (CPLP) or radial endobronchial ultrasound transbronchial lung biopsy (R-EBUS-TBLB) from 443 hospitalized patients in mainland China suspected of pulmonary infections between May 1, 2019 and October 31, 2021. Aim to evaluate the diagnostic performance of mNGS for detecting MTBC and explore differences in the microbial composition in the 2 specimen types.

Results

Among the 443 patients, 46 patients finally were diagnosed with TB, of which 36 patients were detected as MTBC positive by mNGS (8.93%). Striking differences were noticed in the higher detection efficiency of lung biopsy tissue compared with BALF (P = 0.004). There were no significant differences between the 2 specimen types in the relative abundance among the 27 pathogens detected by mNGS from the 36 patients.

Conclusions

This study demonstrates that mNGS could offer an effective detection method of MTBC in BALF or lung tissue biopsy samples in patients suspected of TB infections. When it comes to the situations that BALF samples have limited value to catch pathogens for special lesion sites or the patients have contraindications to bronchoalveolar lavage (BAL) procedures, lung biopsy tissue is an optional specimen for MTBC detection by mNGS. However, whether lung tissue-mNGS is superior to BALF-mNGS in patients with MTBC infection requires further prospective multicenter randomized controlled studies with more cases.

Xpert MTB/RIF Ultra versus Xpert MTB/RIF for diagnosis of tuberculous pleural effusion: A systematic review and comparative meta-analysis

Objective

We compared diagnostic accuracy of pleural fluid Xpert MTB/RIF (Xpert) and Xpert MTB/RIF Ultra (Ultra) assays for diagnosing tuberculous pleural effusion (TPE), through systematic review and comparative meta-analysis.

Methods

We searched PubMed and Embase databases for publications reporting diagnostic accuracy of Xpert or Ultra for TPE. We used bivariate random-effects modeling to summarize diagnostic accuracy information from individual studies using either mycobacterial culture or composite criteria as reference standard. We performed meta-regression through hierarchical summary receiver operating characteristic (HSROC) modeling to evaluate comparative performance of the two tests from studies reporting diagnostic accuracy of both in the same study population.

Results

We retrieved 1097 publications, and included 74 for review. Summary estimates for sensitivity and specificity for Xpert were 0.52 (95% CI 0.43–0.60, I² 82.1%) and 0.99 (95% CI 0.97–0.99, I² 85.1%), respectively, using culture-based reference standard; and 0.21 (95% CI 0.17–0.26, I² 81.5%) and 1.00 (95% CI 0.99–1.00, I² 37.6%), respectively, using composite reference standard. Summary estimates for sensitivity and specificity for Ultra were 0.68 (95% CI 0.55–0.79, I² 80.0%) and 0.97 (95% CI 0.97–0.99, I² 92.1%), respectively, using culture-based reference standard; and 0.47 (95% CI 0.40–0.55, I² 64.1%) and 0.98 (95% CI 0.95–0.99, I² 54.8%), respectively, using composite reference standard. HSROC meta-regression yielded relative diagnostic odds ratio of 1.28 (95% CI 0.65–2.50) and 1.80 (95% CI 0.41–7.84) respectively in favor of Ultra, using culture and composite criteria as reference standard.

Conclusion

Ultra provides superior diagnostic accuracy over Xpert for diagnosing TPE, mainly because of its higher sensitivity.

Efficacy of the Xpert Mycobacterium tuberculosis/rifampicin assay for diagnosing sputum-smear negative or sputum-scarce pulmonary tuberculosis in bronchoalveolar lavage fluid

OBJECTIVE

To evaluate he diagnostic performance of the Xpert Mycobacterium tuberculosis/Rifampin (MTB/RIF) assay in bronchoalveolar lavage fluid (BALF).

METHODS

We retrospectively reviewed the clinical data from 671 sputum-smear negative or sputum-scarce adult patients with suspected pulmonary tuberculosis (PTB) who had an Xpert MTB/RIF assay performed on BALF. The diagnostic performance of the Xpert MTB/RIF assay, smear microscopy (SM) and MTB culture was evaluated using MTB culture or final clinical diagnosis as the reference standard.

RESULTS

Compared with MTB culture, the sensitivity and specificity were 87.8% and 72.7% for the Xpert MTB/RIF assay and 11.0% and 99.2% for SM, respectively. Compared with final diagnosis, diagnostic performance was 58.9% and 83.9% for the Xpert MTB/RIF assay, 5.0% and 98.3% for SM, and 43.3% and 100% for culture, for sensitivity and specificity respectively. The Xpert MTB/RIF assay had low specificity and high sensitivity. When very low results were re-evaluated and considered MTB-negative, the specificity increased significantly. The sensitivity remained higher than SM and was similar to that of culture.

CONCLUSIONS

The Xpert MTB/RIF assay adds microbiologic evidence to clinical decisions; however, close attention should be paid to very low semi-quantitative positive results.

A retrospective study on the combined biomarkers and ratios in serum and pleural fluid to distinguish the multiple types of pleural effusion

Purpose

Pleural effusion (PE) is a common clinical manifestation, and millions of people suffer from pleural disease. Herein, this retrospective study was performed to evaluate the biomarkers and ratios in serum and pleural fluid (PF) for the differential diagnosis of the multiple types of PE and search for a new diagnostic strategy for PE.

Methods

In-patients, who developed tuberculous PE (TPE), malignant PE (MPE), complicated parapneumonic effusion (CPPE), uncomplicated PPE (UPPE), or PE caused by connective tissue diseases (CTDs) and underwent thoracentesis at Peking University People’s Hospital from November 2016 to April 2019, were included in this study. Eleven biomarkers and their ratios in serum and PF were investigated and compared between pairs of the different PE groups, and a decision-tree was developed.

Results

Totally 112 PE cases, including 25 MPE, 33 TPE, 19 CPPE, 27 UPPE, and 8 PE caused by CTDs, were reviewed. Biomarkers and ratios showed good diagnostic performance with high area under the curve values, sensitivities, and specificities for the differential diagnosis of the multiple types of PE. According to the decision-tree analysis, the combination of adenosine deaminase (ADA), serum albumin, serum lactate dehydrogenase, total protein, PF-LDH/ADA, and PF-LDH/TP provided the best predictive capacity with an overall accuracy of 84.8%; the sensitivity and specificity for TPE diagnosis were 100% and 98.7%, respectively.

Conclusion

The biomarkers and ratios showed good diagnostic performance, and a decision-tree with an overall accuracy of 84.8% was developed to differentiate the five types of PE in clinical settings.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12890-021-01459-w.

Aptamer Detection of Mycobaterium tuberculosis Mannose-Capped Lipoarabinomannan in Lesion Tissues for Tuberculosis Diagnosis

Tuberculosis (TB) is the leading infectious cause of mortality worldwide. However, the diagnosis of TB, especially extrapulmonary TB (EPTB) diagnosis from lesion tissues, remains a challenge. Nucleic acid aptamers are analogous to antibodies and have advantages of easier modification, high specificity, and affinity. Mannose-capped lipoarabinomannan (ManLAM) is a unique surface lipoglycan component or constantly released from mycobacterium tuberculosis (M.tb) cell wall, which makes it a perfect candidate biomarker for TB diagnosis. Our present study aims to establish M.tb ManLAM aptamer-based immunohistochemistry (IHC) method for TB diagnosis. We performed TB diagnosis using 263 formalin-fixed paraffin-embedded tissue samples including 213 TB samples (pulmonary TB (PTB) and EPTB), and 8 samples from latent TB infection (LTBI) high risk subjects, and 42 samples from other non-TB patients with ManLAM aptamer-based IHC and routine laboratory TB diagnostic methods parallelly. The sensitivity and specificity of the ManLAM aptamer-based IHC were 86.38% and 92.86%, with much higher sensitivity than those of mycobacterial culture (9.66%) and acid-fast staining (AFS) (43.01%) and comparability to Interferon-gamma Release Assay (IGRA) (84.38%) and GeneXpert (79.31%). High agreement between ManLAM based-IHC and IGRA or GeneXpert for TB diagnosis were observed. Furthermore, ManLAM aptamer-based IHC combination with other routine TB laboratory diagnostic methods significantly increased the sensitivity up to 88.64%–97.92%. As our knowledge, this is the first report about aptamer-based IHC for disease diagnosis. Thus, ManLAM aptamer-based IHC has potentials for TB diagnosis, including PTB, and EPTB, and assists the diagnosis of LTBI with high effectiveness, feasibility, and easy production.