Xpert MTB/RIF assay for diagnosis of extrapulmonary tuberculosis in children: a systematic review and meta-analysis

Pediatric Tuberculosis: A Review of Evidence-Based Best Practices for Clinicians and Health Care Providers

Advances in pediatric TB care are promising, the result of decades of advocacy, operational and clinical trials research, and political will by national and local TB programs in high-burden countries. However, implementation challenges remain in linking policy to practice and scaling up innovations for prevention, diagnosis, and treatment of TB in children, especially in resource-limited settings. There is both need and opportunity to strengthen clinician confidence in making a TB diagnosis and managing the various manifestations of TB in children, which can facilitate the translation of evidence to action and expand access to new tools and strategies to address TB in this population. This review aims to summarize existing guidance and best practices for clinicians and health care providers in low-resource, TB-endemic settings and identify resources with more detailed and actionable information for decision-making along the clinical cascade to prevent, find, and cure TB in children.

Clinical, Laboratory and Radiological Correlates of Xpert MTB/RIF Assay Study in Cerebrospinal Fluid in CNS Tuberculosis

BACKGROUND

Cerebrospinal fluid (CSF) Xpert MTB/RIF assay is an initial test for the diagnosis of tuberculous meningitis (TBM). Nevertheless, it is not very clear which of the factors govern CSF-Gene Xpert/MTB positivity.

OBJECTIVE

Hence, we aimed to assess the relationship, if any, between the clinical, laboratory and radiological parameters of the central nervous system (CNS) tuberculosis patients and the Gene Xpert study in CSF in such patients.

METHODS AND MATERIAL

First, we studied 200 patients with CNS tuberculosis according to the case definition, and subsequently, we performed a Gene Xpert study on the CSF of these patients. Then, we correlated the clinical, radiological, and CSF criteria with the Gene Xpert positivity using the univariate binary logistic regression method via SPSS 20 (P-value <0.05).

RESULTS

Seventy-five (37.5%) patients (57.3% females) of median 24 years of age, were CSF-Gene Xpert/MTB-positive and 125 (62.5%) patients were negative. The mean duration of illness (P = 0.017), weight loss or failure to thrive (P < 0.001), loss of consciousness or seizure (P = 0.001), signs of meningeal irritation (P = 0.027), stage III of TBM (P < 0.001), evidence of dissemination (P = 0.003), basal exudates (P = 0.004), hydrocephalus (P = 0.018), CSF lymphocytic predominance (P < 0.001), and reduced CSF glucose (P = 0.011) correlated significantly with positive the Gene Xpert/MTB results. Also, Gene Xpert had a sensitivity of 80% and a specificity of 74.84% against culture Xpert.

CONCLUSIONS

Xpert MTB/RIF might be more useful in the later stages of the disease and those with more severe disease.

Pediatric Drug-Resistant Tuberculosis: The Current and Future Prospects for Management and Prevention

In the continued battle against one of the oldest enemies known to mankind, Mycobacterium tuberculosis (MTB), the emergence of drug resistance to antituberculosis drugs among children poses multiple challenges for early detection and treatment. Molecular diagnostics and newer drugs like bedaquiline and delamanid have strengthened the armamentarium and helped design convenient, safe, and child-friendly therapeutic regimens against drug-resistant tuberculosis (TB). Preventive strategies like treatment of TB infection among children living in close contact with patients with drug-resistant TB and effective vaccines against TB are currently in the investigative stages of development and implementation. In addition to the implementation of recent novel diagnostics and treatment modalities, effective psychosocial and nutritional support, as well as dedicated monitoring for compliance and adverse effects, are crucial determinants for successful treatment outcomes in these children.

Xpert MTB/RIF Assay for the Diagnosis of Lymph Node Tuberculosis in Children: A Systematic Review and Meta-Analysis

Background: Lymph node tuberculosis (LNTB) is the leading type of extrapulmonary tuberculosis (EPTB) causing death in children. The Xpert MTB/RIF assay is a novel rapid test for the diagnosis of LNTB. Although previous evidence suggests that Xpert is reliably accurate in diagnosing EPTB in children, information is lacking for the specific type of LNTB in children. The aim of this study was to systematically assess the accuracy and reliability of Xpert for the diagnosis of LNTB in children. Methods: We systematically searched four databases, Embase, Cochrane Library, PubMed, and Web of Science, which extracted relevant data according to predefined inclusion and exclusion criteria. The data were analyzed by meta-Disc 1.4 and Stata 12.0 software to determine sensitivity, specificity, diagnostic odds ratio (DOR), etc. Results: A total of 646 samples from 8 studies were included in the analysis. The pooled sensitivity, specificity, negative likelihood ratio (NLR), positive likelihood ratio (PLR,) and combined diagnostic odds ratio (DOR) of Xpert for all samples were 0.79 (95% CI 0.70, 0.87), 0.90 (95% CI 0.86, 0.92), 0.29 (95% CI 0.19, 0.43), 7.20 (95% CI 3.32, 15.60), and 37.56 (95% CI 13.04, 108.15), respectively. The area under the curve (AUC) of the summary receiver operating characteristic (sROC) curve was 0.9050. Conclusion: Overall, Xpert showed moderate sensitivity and high specificity compared with culture in the diagnosis of LNTB in children. In addition, after analyzing the combined diagnostic odds ratio and positive LR, our study showed that Xpert has excellent diagnostic accuracy.

Performance of TB-LAMP in the Diagnosis of Tuberculous Empyema Using Samples Obtained From Pleural Decortication

Purpose

To evaluate the performance of TB-LAMP in the diagnosis of TB empyema using pleural tissue specimens obtained during pleural decortication.

Methods

Using the clinical records and the different diagnostic test results of patients who underwent pleural decortication in a TB-designated hospital over 3.5 years, we calculated the sensitivity, specificity positive predictive, and negative predictive values of the pathology, MGIT 960 culture, and TB-LAMP obtained by using pleural tissue specimens against the etiologic diagnosis and composite clinical reference standard (CCRS) as the reference standards.

Result

A total of 304 patients' records were extracted. All these patients had gone through pleural decortication. When the etiologic diagnosis was used as the reference, the sensitivity of TB-LAMP in identifying TB empyema was 77.8% (compared to 10.6% of MGIT 960 P < 0.05). The sensitivity of MGIT 960, pathology, and TB-LAMP was 8.2%, 77.7%, and 67.2% against CCRS as the reference; and the specificity of the three was 100.0, 100.0, and 96.2% against the same standard. A combination of pathology and TB-LAMP would increase the sensitivity and specificity to 84.7 and 96.0%. Using TB-LAMP to diagnose TB empyema using pleural tissue samples obtained from pleural decortication was faster with satisfactory performance.

Conclusion

TB-LAMP has great potential in faster and more accurate diagnosis of TB empyema. Our findings provide insights for optimizing diagnostic algorithms for TB empyema.

Research Questions and Priorities for Pediatric Tuberculosis: A Survey of Published Systematic Reviews and Meta-Analyses

Background. Advancing a research agenda designed to meet the specific needs of children is critical to ending pediatric TB epidemic. Systematic reviews are increasingly informing policies in pediatric tuberculosis (TB) care and control. However, there is a paucity of information on pediatric TB research priorities. Methodology. We searched MEDLINE, EMBASE, Web of Science, and the Cochrane Library for systematic reviews and meta-analyses on any aspect related to pediatric TB published between 2015 and 2021. We used the UK Health Research Classification System (HRCS) to help us classify the research questions and priorities. Findings. In total, 29 systematic reviews, with 84 research questions, were included in this review. The four most common research topics in the area of detection were 43.33% screening and diagnosis of TB, 23.33% evaluation of treatments and therapeutic interventions, 13.34% TB etiology and risk factors, and 13.34% prevention of disease and conditions and promotion of well-being. The research priorities focused mainly on evaluating TB diagnosis by improving yield through enhanced in specimen collection or preparation and evaluating of bacteriological TB diagnostic tests. Other topics of future research were developing a treatment for TB in children, assessing the use of IPT in reducing TB-associated morbidity, evaluating the prioritization of an IPT-friendly healthcare environment, and providing additional guidance for the use of isoniazid in the prevention of TB in HIV-infected children. Conclusion. There is a need for more systematic reviews on pediatric TB. The review identified several key priorities for future pediatric TB research mainly in the domain of (1) “Detection, screening and diagnosis,” “Development of Treatments and Therapeutic Interventions,” and “Prevention of Disease and Conditions, and Promotion of Well-Being.” These domains are very relevant in the research component of the roadmap towards ending TB in children. It also will serve as an additional action in the WHO End TB strategy.

A Difficult Case of Pyrexia of Unknown Origin

This is the case of a 15-y-old boy who presented with fever and back pain with MRI features of spondylitis. A CT-guided vertebral biopsy showed acute and chronic inflammatory cells and grew Pseudomonas aeruginosa on aerobic culture. The child was treated for 2 wk with antibiotics with no response. Meanwhile, he developed new lung, liver, and splenic lesions on CT imaging. Empiric antitubercular therapy was then started and continued for 8 wk during which time there was progressive clinical deterioration. At this time the patient underwent bronchoscopy with lavage and endoscopic ultrasound-guided subcarinal lymph node and lung biopsy. The Xpert MTB/Rif ULTRA was "trace positive" in the bronchoscopic lavage with indeterminate rifampicin resistance, while it was negative in lymph node and lung biopsy. The lymph node and lung biopsy histopathology showed nonspecific inflammatory changes with no granulomas or malignant cells. In view of the positive Xpert ULTRA with indeterminate rifampicin resistance and no response to first-line drugs, treatment with second-line antitubercular drugs was initiated. The clinical condition continued to deteriorate; here the imaging findings were reviewed again and repeat aspiration cytology and biopsy from intra-abdominal nodes was carried out. This yielded the diagnosis of Hodgkin lymphoma. The patient had stage IVB disease. He responded well to standard chemotherapy and is currently in remission. The case illustrates the need to avoid empiric therapy, repeat invasive procedures if so needed, choose the site/method of biopsy appropriately and interpret results of investigations carefully when evaluating a patient with pyrexia of unknown origin.

The diagnostic impact of implementing a molecular-based algorithm to standard mycobacterial screening at a reference laboratory with an intermediate prevalence for non-respiratory samples

Rapid, reliable results can be given by molecular, direct detection and identification of the Mycobacterium tuberculosis (MTB/Mtb) complex from clinical samples. The Xpert MTB/RIF assay is an assay that has been availablefor more than a decade for identification of Mycobacterium tuberculosis and resistance to rifampicin. However, there is minimal evidence on its clinical usefulness in paucibacillary, non-respiratory samples. The Xpert MTB/RIF assay clinical utility index, its diagnostic characteristics and the number required to diagnose 2935 non-respiratory specimens submitted for routine mycobacterial work-up in a reference laboratory in an intermediate prevalence setting per specimen form were evaluated. The Xpert MTB/RIF assay showed a variable clinical utility index and number required to diagnose (NND) depending on the type of specimen, which was moderate in tissue biopsies (NND = 1.8) and excellent in pus and urine samples, compared to acid-fast microscopy and culture as a gold standard technique (NND = 1.1 and 1.2). Microscopy, on the other hand, consistently showed a weak to fair index of clinical usefulness in all specimen forms, with in NND of 2.3-12.5. The NND for detecting tuberculous infection in the cerebrospinal fluid by the Xpert MTB/RIF assay was noted to be 1.2, with a moderate clinical utility index of 0.8. The evidence presented indicates that the overall appropriate diagnostic utility of the Xpert MTB/RIF assay is clinically successful in most non-respiratory samples. To check the cost-effectiveness and prognostic effect of integrating this completely automated molecular-based assay into the routine testing algorithm for non-respiratory mycobacterial specimens, further data must be collected.

Tuberculosis among children and adolescents in Rio de Janeiro, Brazil - Focus on extrapulmonary disease

OBJECTIVE

To compare the socio-demographic, clinical, and diagnostic characteristics and treatment outcomes between extrapulmonary tuberculosis (EPTB) and pulmonary tuberculosis (PTB) in children and adolescents in Rio de Janeiro, a high TB-burdened Brazilian city.

METHODS

This retrospective study used data from patients with EPTB and PTB aged 0 - 18 years, notified on two national databases from 2014 to 2016.

RESULTS

Among the 1008 patients, 144 (14.2%) had EPTB. Patients with EPTB showed higher odds of hospital-based diagnosis (odds ratio (OR): 6.76 [95% confidence interval (95% CI): 4.62-9.90]; p < 0.001), no laboratory confirmation (OR: 4.9 2.14 [95% CI: 3.07 - 7.85]; p < 0.001), and being <14 years old (OR: 3.13 [95% CI: 2.18-4.49]) than those with PTB. A diagnosis without laboratory investigation was observed among 301/864 (34.8%) patients with PTB, 48/144 (33.3%) with EPTB, and among those aged under five years with EPTB (15/27 [55.6%]). TB deaths were more frequent in patients with EPTB (5/144 [3.5%]) than in those with PTB (4/864[0.5%]) (p = 0.001); 4/5 (80%) TB deaths were due to TB meningitis; 50% died within 14 days of diagnosis.

CONCLUSIONS

EPTB remains a clinical diagnostic challenge that needs to be addressed to fully benefit from the higher sensitivity laboratory investigations.