Multiple microbiologic tests for tuberculosis improve diagnostic yield of bronchoscopy in medically complex patients

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.

The Usefulness of Bronchoscopy in the Diagnosis of Mycobacterium tuberculosis Complex Species Infection

BACKGROUND: Pulmonary tuberculosis is an active chronic infection of the lungs. It is still a public health problem globally caused by the Mycobacterium tuberculosis Complex (MTBC). These species are difficult to determine only by conventional tests. The clinical manifestations are almost similar between the strains and cause diagnosis delays. Prolonged and intolerable MTBC therapy inhibits infection control. AIM: This study aims to evaluate the usefulness of bronchoscopy in diagnosing the MTBC species infection. METHODS: This study recruited patients with difficulty expectorating sputum. Pulmonary tuberculosis was diagnosed with the Xpert MTB/RIF assay. This study assessed sputum Acid Fast Bacilli (AFB) staining, chest X-rays with active pulmonary tuberculosis, characteristics of Bronchoalveolar lavage (BAL), and bronchoscopic findings based on the Chung classification. The BAL of polymerase chain reaction analysis using RD9 and TbD1 primers to determine MTBC species. RESULTS: Out of the 30 cases, M. tuberculosis and Mycobacterium bovis 24 (80.0%) and 6 (20.0%) were identified in BAL fluid. There were 12 cases (40.0%) with AFB sputum test, and 25 (83.3%) of the Xpert MTB/RIF detected tuberculosis cases. All chest X-rays showed infiltrated and 22 (73.3%) pulmonary ectasis. There was a significant difference in MTBC species between sputum and BAL fluid (p < 0.05). The ulcerative type of bronchoscopy findings was significantly different in MTBC species (p < 0.05) and there was no macroscopic BAL fluid difference (p > 0.05). CONCLUSIONS: Bronchoscopy is a specimen collection technique that is beneficial in determining the diagnosis of MTBC. Analysis of BAL with molecular methods contributes to identifying MTBC species quickly and accurately.

Additional Usefulness of Bronchoscopy in Patients with Initial Microbiologically Negative Pulmonary Tuberculosis: A Retrospective Analysis of a Korean Nationwide Prospective Cohort Study

Purpose

Bronchoscopy is widely used for microbiological diagnosis of patients with minimal sputum production. However, the usefulness of bronchoscopy in patient groups who benefit from subsequent microbiological confirmation has not been established.

Patients and Methods

We retrospectively analyzed Korean tuberculosis (TB) cohort data from September 2018 to October 2019 to evaluate the usefulness of bronchoscopy in patients with microbiologically negative pulmonary TB (based on initial sputum polymerase chain reaction and culture results). The primary outcome was the proportion of microbiological diagnoses made after bronchoscopy. Secondary outcomes were the predictors of microbiological confirmation and the percentage of additional resistance detection after bronchoscopy.

Results

A total of 5194 patients were diagnosed with pulmonary TB, 937 of whom were microbiologically negative for pulmonary TB based on the initial sputum findings. Of these, 319 patients underwent bronchoscopy, and further microbiological confirmation was achieved in 157 (49.1%) patients. The predictors of microbiological confirmation after bronchoscopy were age >65 years, female sex, and low body mass index (BMI). The rate of additional resistance detection was 10.5% (multidrug resistant/rifampin-resistant 3.8%; isoniazid-resistant 5.7%).

Conclusion

Bronchoscopy can be used for the detection of resistant pathogens. Bronchoscopy should be considered for microbiologically negative pulmonary TB in women aged >65 years and with low BMI for subsequent microbiological confirmation.

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.

Diagnoses from lung specimen collected through flexible bronchoscopy from patients in a tertiary hospital in Dar es Salaam Tanzania: a retrospective cross-sectional study

BACKGROUND

Flexible bronchoscopy enables visualization of the respiratory airway mucosa from the oropharynx to third generation branching of the tracheobronchial tree. Bronchoscopic diagnoses vary from one locality to the other in accordance to the locality specific risk factors for lung diseases. This study aimed at describing diagnoses of all specimen of patients who underwent flexible bronchoscopy at Muhimbili National Hospital from January 2013 to November 2017.

METHODS

A retrospective hospital-based cross sectional study was conducted among 451 patients. Data was collected from archives and included both demographic and clinical variables. Descriptive statistics were used to summarize the study findings.

RESULTS

There was a 3 fold increase in the number of patients who underwent flexible bronchoscopy from 57 cases in 2013 to 180 cases in 2017. About 39% (174/451) of patients underwent lung biopsies while 64.5% (291/451) underwent bronchioalveolar lavage, bronchial washings or brush cytology, alone or in combination with biopsy. Generally, 64.4% (112/174) of all lung biopsies were malignant. Adenocarcinoma was the most common diagnosis seen in 33.9% (59/174). Of 76 cytological samples which were sent for bacterial culture and sensitivity, 11/76 (11.8%) were culture positive. A total of 6 (10.7%) out of 56 samples which were sent for GeneXpert MTB/RIF tested positive for M.tuberculosis.

CONCLUSION

Adenocarcinoma was the most common diagnosis. Bacterial and mycobacterial infections were among the most reported findings in cytological samples. Suspicious tuberculosis lesions during bronchoscopy made it possible to diagnose tuberculosis which was hard to diagnose before patients were sent for bronchoscopy.