Bacteriological diagnosis of childhood TB: a prospective observational study

Update on the diagnosis and treatment of tuberculosis

According to World Health Organization estimates, more than 1 million patients aged less than 15 years develop tuberculosis (TB) each year worldwide. In some regions, up to 25% of new TB cases are caused by drug-resistant strains. Although Spain is considered a low-incidence country, several hundred children and adolescents develop TB each year. The importance of paediatric TB has been minimized for years due to the lack of microbiological confirmation in many patients and because these patients are not usually contagious. Nevertheless, in the past 15 years there have been major improvements in the epidemiological reporting of TB in children and adolescents, new immunodiagnostic tests have been developed, molecular methods that allow rapid microbiological diagnosis and detection of variants associated with drug resistance have become available, novel second-line antituberculosis drugs have been discovered, including for paediatric use, and the results of clinical trials have validated shorter courses of treatment for some patients. This document, developed by a group of experts from the Sociedad Española de Infectología Pediátrica and the Sociedad Española de Neumología Pediátrica, updates and complements the previous guidelines for the diagnostic and therapeutic management of children with TB in Spain based on the newly available scientific evidence.

Childhood Tuberculosis in Mongolia: Trends and Estimates, 2010-2030

Mongolia was listed among the 30 countries with a high tuberculosis burden in 2021. Approximately 10-11% of the tuberculosis cases are of children, which is higher than the global average (6.0%). As children are a vulnerable population, it is important to understand the current situation and prioritize the development of tuberculosis prevention strategies. However, only few studies have addressed childhood tuberculosis in Mongolia. Therefore, we aimed to describe the characteristics of childhood tuberculosis and to show its trends and estimates in Mongolia. We performed descriptive and trend analyses on secondary data from the National Center for Communicable Diseases from 2010 to 2020. A total of 4,242 childhood tuberculosis cases, compiled from nine districts of the capital city and 21 provinces, were analyzed. We found that tuberculosis occurred more frequently in school-age children, and 71.8% of the all cases were an extrapulmonary tuberculosis. Trend analysis revealed that childhood tuberculosis continuously increased with fluctuations from 2018 onwards. The central region, including the capital city of Ulaanbaatar, is the most tuberculosis-burdened. Childhood tuberculosis is estimated to increase in the central region and decrease in the others from 2021 to 2030. Our findings showed that the national childhood tuberculosis trend is increasing, although there are differences in the pattern between regions. Further studies are needed to identify the determinant factors of regional differences, and age-specific public health interventions, such as scale-up screening and preventive treatment, are in demand in high-prevalence areas.

A systematic review on Correlates of Risk of TB disease in children and adults

BACKGROUND

Tuberculosis (TB) remains one of the leading causes of death in the world. Targeted treatment to prevent progression from TB exposure and infection to disease is a key element of WHO End-TB strategy. A systematic review to identify and develop correlates of risk (COR) of TB disease is timely.

METHOD

EMBASE, MEDLINE, PUBMED were searched using relevant keywords and MeSH terms published between 2000 and 2020 on COR of TB disease in children and adults. Preferred Reporting Items for Systematic reviews and Meta-analysis (PRISMA) framework was used for structuring and reporting of outcomes. Risk of bias was assessed using Quality Assessment of Diagnostic Accuracy Studies tool-2 (QUADAS-2).

RESULTS

4105 studies were identified. Following eligibility screening, 27 studies were quality assessed. Risk of bias was high in all studies. Broad variations in COR type, study population, methodology and result reporting were observed. Tuberculin skin test (TST) and interferon gamma release essays (IGRA) are poor COR. Transcriptomic signatures although promising require validation studies to assess wider applicability. Performance consistency of other CORs-cell marker, cytokines and metabolites are much needed.

CONCLUSION

This review identifies the need for a standardized approach to identify a universally applicable COR signature to achieve the WHO END-TB targets.

Xpert MTB/RIF and Xpert MTB/RIF Ultra assays for active tuberculosis and rifampicin resistance in children

BACKGROUND

Every year, at least one million children become ill with tuberculosis and around 200,000 children die. Xpert MTB/RIF and Xpert Ultra are World Health Organization (WHO)-recommended rapid molecular tests that simultaneously detect tuberculosis and rifampicin resistance in adults and children with signs and symptoms of tuberculosis, at lower health system levels. To inform updated WHO guidelines on molecular assays, we performed a systematic review on the diagnostic accuracy of these tests in children presumed to have active tuberculosis.

OBJECTIVES

Primary objectives • To determine the diagnostic accuracy of Xpert MTB/RIF and Xpert Ultra for (a) pulmonary tuberculosis in children presumed to have tuberculosis; (b) tuberculous meningitis in children presumed to have tuberculosis; (c) lymph node tuberculosis in children presumed to have tuberculosis; and (d) rifampicin resistance in children presumed to have tuberculosis - For tuberculosis detection, index tests were used as the initial test, replacing standard practice (i.e. smear microscopy or culture) - For detection of rifampicin resistance, index tests replaced culture-based drug susceptibility testing as the initial test Secondary objectives • To compare the accuracy of Xpert MTB/RIF and Xpert Ultra for each of the four target conditions • To investigate potential sources of heterogeneity in accuracy estimates - For tuberculosis detection, we considered age, disease severity, smear-test status, HIV status, clinical setting, specimen type, high tuberculosis burden, and high tuberculosis/HIV burden - For detection of rifampicin resistance, we considered multi-drug-resistant tuberculosis burden • To compare multiple Xpert MTB/RIF or Xpert Ultra results (repeated testing) with the initial Xpert MTB/RIF or Xpert Ultra result SEARCH METHODS: We searched the Cochrane Infectious Diseases Group Specialized Register, MEDLINE, Embase, Science Citation Index, the Cumulative Index to Nursing and Allied Health Literature (CINAHL), Scopus, the WHO International Clinical Trials Registry Platform, ClinicalTrials.gov, and the International Standard Randomized Controlled Trials Number (ISRCTN) Registry up to 29 April 2019, without language restrictions.

SELECTION CRITERIA

Randomized trials, cross-sectional trials, and cohort studies evaluating Xpert MTB/RIF or Xpert Ultra in HIV-positive and HIV-negative children younger than 15 years. Reference standards comprised culture or a composite reference standard for tuberculosis and drug susceptibility testing or MTBDRplus (molecular assay for detection of Mycobacterium tuberculosis and drug resistance) for rifampicin resistance. We included studies evaluating sputum, gastric aspirate, stool, nasopharyngeal or bronchial lavage specimens (pulmonary tuberculosis), cerebrospinal fluid (tuberculous meningitis), fine needle aspirates, or surgical biopsy tissue (lymph node tuberculosis).

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted data and assessed study quality using the Quality Assessment of Studies of Diagnostic Accuracy - Revised (QUADAS-2). For each target condition, we used the bivariate model to estimate pooled sensitivity and specificity with 95% confidence intervals (CIs). We stratified all analyses by type of reference standard. We assessed certainty of evidence using the GRADE approach.

MAIN RESULTS

For pulmonary tuberculosis, 299 data sets (68,544 participants) were available for analysis; for tuberculous meningitis, 10 data sets (423 participants) were available; for lymph node tuberculosis, 10 data sets (318 participants) were available; and for rifampicin resistance, 14 data sets (326 participants) were available. Thirty-nine studies (80%) took place in countries with high tuberculosis burden. Risk of bias was low except for the reference standard domain, for which risk of bias was unclear because many studies collected only one specimen for culture. Detection of pulmonary tuberculosis For sputum specimens, Xpert MTB/RIF pooled sensitivity (95% CI) and specificity (95% CI) verified by culture were 64.6% (55.3% to 72.9%) (23 studies, 493 participants; moderate-certainty evidence) and 99.0% (98.1% to 99.5%) (23 studies, 6119 participants; moderate-certainty evidence). For other specimen types (nasopharyngeal aspirate, 4 studies; gastric aspirate, 14 studies; stool, 11 studies), Xpert MTB/RIF pooled sensitivity ranged between 45.7% and 73.0%, and pooled specificity ranged between 98.1% and 99.6%. For sputum specimens, Xpert Ultra pooled sensitivity (95% CI) and specificity (95% CI) verified by culture were 72.8% (64.7% to 79.6%) (3 studies, 136 participants; low-certainty evidence) and 97.5% (95.8% to 98.5%) (3 studies, 551 participants; high-certainty evidence). For nasopharyngeal specimens, Xpert Ultra sensitivity (95% CI) and specificity (95% CI) were 45.7% (28.9% to 63.3%) and 97.5% (93.7% to 99.3%) (1 study, 195 participants). For all specimen types, Xpert MTB/RIF and Xpert Ultra sensitivity were lower against a composite reference standard than against culture. Detection of tuberculous meningitis For cerebrospinal fluid, Xpert MTB/RIF pooled sensitivity and specificity, verified by culture, were 54.0% (95% CI 27.8% to 78.2%) (6 studies, 28 participants; very low-certainty evidence) and 93.8% (95% CI 84.5% to 97.6%) (6 studies, 213 participants; low-certainty evidence). Detection of lymph node tuberculosis For lymph node aspirates or biopsies, Xpert MTB/RIF pooled sensitivity and specificity, verified by culture, were 90.4% (95% CI 55.7% to 98.6%) (6 studies, 68 participants; very low-certainty evidence) and 89.8% (95% CI 71.5% to 96.8%) (6 studies, 142 participants; low-certainty evidence). Detection of rifampicin resistance Xpert MTB/RIF pooled sensitivity and specificity were 90.0% (67.6% to 97.5%) (6 studies, 20 participants; low-certainty evidence) and 98.3% (87.7% to 99.8%) (6 studies, 203 participants; moderate-certainty evidence).

AUTHORS' CONCLUSIONS

We found Xpert MTB/RIF sensitivity to vary by specimen type, with gastric aspirate specimens having the highest sensitivity followed by sputum and stool, and nasopharyngeal specimens the lowest; specificity in all specimens was > 98%. Compared with Xpert MTB/RIF, Xpert Ultra sensitivity in sputum was higher and specificity slightly lower. Xpert MTB/RIF was accurate for detection of rifampicin resistance. Xpert MTB/RIF was sensitive for diagnosing lymph node tuberculosis. For children with presumed tuberculous meningitis, treatment decisions should be based on the entirety of clinical information and treatment should not be withheld based solely on an Xpert MTB/RIF result. The small numbers of studies and participants, particularly for Xpert Ultra, limits our confidence in the precision of these estimates.

Integrating pediatric TB services into child healthcare services in Africa: study protocol for the INPUT cluster-randomized stepped wedge trial

Background

Tuberculosis is among the top-10 causes of mortality in children with more than 1 million children suffering from TB disease annually worldwide. The main challenge in young children is the difficulty in establishing an accurate diagnosis of active TB.

The INPUT study is a stepped-wedge cluster-randomized intervention study aiming to assess the effectiveness of integrating TB services into child healthcare services on TB diagnosis capacities in children under 5 years of age.

Methods

Two strategies will be compared: i) The standard of care, offering pediatric TB services based on national standard of care; ii) The intervention, with pediatric TB services integrated into child healthcare services: it consists of a package of training, supportive supervision, job aids, and logistical support to the integration of TB screening and diagnosis activities into pediatric services. The design is a cluster-randomized stepped-wedge of 12 study clusters in Cameroon and Kenya. The sites start enrolling participants under standard-of-care and will transition to the intervention at randomly assigned time points. We enroll children aged less than 5 years with a presumptive diagnosis of TB after obtaining caregiver written informed consent. The participants are followed through TB diagnosis and treatment, with clinical information prospectively abstracted from their medical records.

The primary outcome is the proportion of TB cases diagnosed among children < 5 years old attending the child healthcare services. Secondary outcomes include: number of children screened for presumptive active TB; diagnosed; initiated on TB treatment; and completing treatment. We will also assess the cost-effectiveness of the intervention, its acceptability among health care providers and users, and fidelity of implementation.

Discussion

Study enrolments started in May 2019, enrolments will be completed in October 2020 and follow up will be completed by June 2021. The study findings will be disseminated to national, regional and international audiences and will inform innovative approaches to integration of TB screening, diagnosis, and treatment initiation into child health care services.

Trial resistration

NCT03862261, initial release 12 February 2019.

Clinical Spectrum of Pediatric Tuberculosis: A Microbiological Correlation from a Tertiary Care Center

AIM AND OBJECTIVES

The paucibacillary nature of pediatric tuberculosis (TB) makes diagnosis difficult. The aim of the study was to correlate the clinical spectrum of pediatric TB with microbiological diagnosis.

MATERIALS AND METHODS

Specimens from clinically suspected pediatric TB cases were subjected to Ziehl-Neelsen staining, culture on Lowenstein-Jensen medium and cartridge-based nucleic acid amplification test (CB-NAAT) for TB.

RESULTS

Pulmonary TB was the predominant form affecting 36 of 62 (58%) patients. Tubercular meningitis was the commonest form of extrapulmonary type and affected 13 of 26 (50%) children. Microbiological diagnosis by any of the above methods could be established in 35 (56.45%) cases. While 33 of 36 (92%) patients diagnosed with pulmonary TB had radiological findings, of which only 25 (76%) could be microbiologically confirmed, only 24 of 31 (77%) patients with extrapulmonary symptoms had radiological evidence and microbiological confirmation could be achieved in 4 (17%) of these.

CONCLUSION

An integrated approach of diagnosis, including clinical-radiological, microbiological and immunological evidence should be stressed on.

Multidrug-resistant tuberculosis infection and disease in children: a review of new and repurposed drugs

The World Health Organization estimates that 10 million new cases of tuberculosis (TB) occurred worldwide in 2017, of which 600,000 were rifampicin or multidrug-resistant (RR/MDR) TB. Modelling estimates suggest that 32,000 new cases of MDR-TB occur in children annually, but only a fraction of these are correctly diagnosed and treated. Accurately diagnosing TB in children, who usually have paucibacillary disease, and implementing effective TB prevention and treatment programmes in resource-limited settings remain major challenges. In light of the underappreciated RR/MDR-TB burden in children, and the lack of paediatric data on newer drugs for TB prevention and treatment, we present an overview of new and repurposed TB drugs, describing the available evidence for safety and efficacy in children to assist clinical care and decision-making.