Induced sputum or gastric lavage for community-based diagnosis of childhood pulmonary tuberculosis?

Utility of interferon-gamma releasing assay for the diagnosis of active tuberculosis in children: A systematic review and meta-analysis

INTRODUCTION

The accurate diagnosis of tuberculosis (TB) in children is essential for its effective management and control. Reliable diagnostic tools that are currently available for identifying TB infection include the in vivo tuberculosis skin test (TST) and ex vivo interferon-gamma release assays (IGRAs). This systematic review and meta-analysis aimed to evaluate the diagnostic accuracy of IGRAs in children.

METHODS

Of the 768 screened studies, 47 met the eligibility criteria. Data from 9065 patients, including 1086 (12.0 %) with confirmed TB, were included in the analysis. The overall quality of the included studies, assessed using the Quality Assessment of Diagnostic Accuracy Studies-2 tool, was unclear.

RESULTS

The calculated pooled sensitivity and specificity of IGRAs in children were 0.85 (95 % confidence interval [CI]: 0.79-0.89) and 0.94 (95 % CI: 0.88-0.97), respectively. Subpopulation analysis revealed that the sensitivities and specificities were as follows: QuantiFERON tests: 0.83 (95 % CI: 0.74-0.89) and 0.93 (95 % CI: 0.87-0.96), T-SPOT: 0.87 (95 % CI: 0.79-0.91) and 0.99 (95 % CI: 0.85-1.00), IGRAs in children under 15 years: 0.77 (95 % CI: 0.43-0.94) and 0.96 (95 % CI: 0.84-0.97), and IGRAs in children under 5 years: 0.85 (95 % CI: 0.52-0.97) and 0.94 (95 % CI: 0.90-0.99), respectively.

CONCLUSIONS

This study demonstrated that the sensitivity and specificity of the IGRAs in children were moderate and high, respectively. Therefore, the IGRAs may be useful for detecting TB infection in children.

CLINICAL TRIAL REGISTRATION

The review protocol was prospectively registered with the University Hospital Medical Information Network Clinical Trials Registry (UMIN000046737).

Position statement on infection screening, prophylaxis, and vaccination of pediatric patients with rheumatic diseases and immunosuppressive therapies, part 3: precautions in situations of surgery, fever, and opportunistic infections

The objective of this study is to provide practical recommendations on the management of pediatric patients with immune-mediated rheumatic diseases receiving immunosuppressive therapies. The recommendations specifically address the cases of surgery, fever, and opportunistic infections (varicella, herpes-zoster, tuberculosis, invasive fungal disease). A qualitative approach was applied. A narrative literature review was performed via Medline. Primary searches were conducted using MeSH terms and free text to identify publications on infections and vaccinations in pediatric patients with immune-mediated rheumatic diseases receiving immunosuppressive therapies. The results were presented and discussed in a nominal group meeting, comprising a committee of 12 pediatric rheumatologists from the Infection Prevention and Treatment Working Group of the Spanish Society of Pediatric Rheumatology. Several recommendations were generated. A consensus procedure was implemented via a Delphi process; this was extended to members of the Spanish Society of Pediatric Rheumatology and Spanish Society of Pediatric Infectious Disease of the Spanish Association of Pediatrics. Participants produced a score ranging from 0 (totally disagree) to 10 (totally agree). Agreement was defined as a vote ≥ 7 by at least 70% of participants. The literature review included more than 400 articles. Overall, 63 recommendations (19 on surgery, fever, and opportunistic infections) were generated and voted by 59 pediatric rheumatologists and other pediatric specialists. Agreement was reached for all 63 recommendations. The recommendations on special situations cover management in cases of surgery, fever, and opportunistic infections (varicella, herpes-zoster, tuberculosis, and invasive fungal disease).  Conclusions: Hereby, we provided consensus and updated of recommendations about the management of special situations such as surgery, fever, and opportunistic in children with immune-mediated rheumatic diseases receiving immunosuppressive therapies. Several of the recommendations depend largely on clinical judgement and specific balance between risk and benefit for each individual and situation. To assess this risk, the clinician should have knowledge of the drugs, the patient's previous situation as well as the current infectious disease, in addition to experience. What is Known: • Infectious diseases and related complications are a major cause of morbidity and mortality in patients with immune-mediated rheumatic diseases. • Information on how to manage the treatment in situations of fever, opportunistic infections, and surgery in children is limited, and guidelines for action are often extrapolated from adults. What is New: • In the absence of strong evidence, a literature review and a Delphi survey were conducted to establish a series of expert recommendations that could support the clinical practice, providing a practical and simple day-to-day approach to be used by pediatric rheumatologists.

Diagnostic value of tNGS vs Xpert MTB/RIF in childhood TB

Objectives

To evaluate the diagnostic value of targeted next generation sequencing (tNGS) in childhood tuberculosis (TB) and compare the accuracy with Xpert MTB/RIF method.

Methods

Children aged ≤18 years with symptoms suggestive of TB during July 2021 to December 2022 at Beijing Children's Hospital were included, and the performances of tNGS and Xpert were evaluated.

Results

A total of 103 children with suspected TB were recruited, including 72 discharge diagnosis of TB and 31 non-TB cases. The mean age was 7.37 ± 4.77 years, and 62.1 % were male. The most common type of specimens was gastric aspirate (GA) (59, 57.3 %). Among all the 72 TB patients, tNGS showed higher sensitivity than Xpert, but the difference was not significant (34.7 %, 25/72 vs 20.8 %, 15/72; P = 0.063). The specificities of tNGS and Xpert were 87.1 % (27/31) and 96.8 % (30/31), respectively (P = 0.162). Among different types of specimen, the highest sensitivity of tNGS on sputum and pus was observed (80.0 %, 4/5), followed by pleural effusion (50.0 %, 2/4). One rifampin resistance and one protionamide resistance were detected in bacteriologically confirmed TB by tNGS.

Conclusion

tNGS had a higher sensitivity but lower specificity compared to Xpert in diagnosis of children TB. tNGS yielded higher sensitivity than Xpert on gastric aspirate and sputum and pus.

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.

The Contribution of Chest Radiography to the Clinical Management of Children Exposed to Tuberculosis

Rationale: Although World Health Organization guidelines emphasize contact investigation for tuberculosis (TB)-exposed children, data that support chest radiography as a useful tool are lacking. Objectives: We evaluated the diagnostic and prognostic information of chest radiography in children exposed to TB and measured the efficacy of isoniazid preventive therapy (IPT) in those with relevant radiographic abnormalities. Methods: Between September 2009 and August 2012, we enrolled 4,468 TB-exposed children who were screened by tuberculin skin testing, symptom assessment, and chest radiography. Those negative for TB disease were followed for 1 year for the occurrence of new TB diagnoses. We assessed the protective efficacy of IPT in children with and without abnormal chest radiographs. Measurements and Main Results: Compared with asymptomatic children with normal chest films, asymptomatic children with abnormal radiographs were 25.1-fold more likely to have coprevalent TB (95% confidence interval [CI], 1.02-613.76) and 26.7-fold more likely to be diagnosed with incident TB disease during follow-up (95% CI, 10.44-68.30). Among the 29 symptom-negative and CXR-abnormal child contacts, 20% (3/15) of the isoniazid recipients developed incident TB, compared with 57% (8/14) of those who did not receive IPT (82% IPT efficacy). Conclusions: Our results strongly support the use of chest radiography as a routine screening tool for the evaluation of child TB contacts, which is readily available. Radiographic abnormalities not usually considered suggestive of TB may indicate incipient or subclinical disease, although TB preventive treatment is adequate in most cases.

Etiology and the challenge of diagnostic testing of community-acquired pneumonia in children and adolescents

Background

Pneumonia is the leading cause of mortality in pediatric population. The etiology of pneumonia in this population is variable and changes according to age and disease severity and where the study is conducted. Our aim was to determine the etiology of community-acquired pneumonia (CAP) in children aged 1 month to 17 years admitted to 13 Colombian hospitals.

Methods

Prospective cohort study. Hospitalized children with radiologically confirmed CAP and ≤ 15 days of symptoms were included and followed together with a control group. Induced sputum (IS) was submitted for stains and cultures for pyogenic bacteria and Mycobacterium tuberculosis, and multiplex PCR (mPCR) for bacteria and viruses; urinary antigens for pneumococcus and Legionella pneumophila; nasopharyngeal swabs for viruses, and paired serology for atypical bacteria and viruses. Additional cultures were taken at the discretion of primary care pediatricians.

Results

Among 525 children with CAP, 71.6% had non-severe pneumonia; 24.8% severe and 3.6% very severe pneumonia, and no fatal cases. At least one microorganism was identified in 84% of children and 61% were of mixed etiology; 72% had at least one respiratory virus, 28% pyogenic bacteria and 21% atypical bacteria. Respiratory syncytial virus, Parainfluenza, Rhinovirus, Influenza, Mycoplasma pneumoniae, Adenovirus and Streptococcus pneumoniae were the most common etiologies of CAP. Respiratory syncytial virus was more frequent in children under 2 years and in severe pneumonia. Tuberculosis was diagnosed in 2.3% of children. IS was the most useful specimen to identify the etiology (33.6%), and blood cultures were positive in 3.6%. The concordance between all available diagnostic tests was low. A high percentage of healthy children were colonized by S. pneumoniae and Haemophilus influenzae, or were infected by Parainfluenza, Rhinovirus, Influenza and Adenovirus.

Conclusions

Respiratory viruses are the most frequent etiology of CAP in children and adolescents, in particular in those under 5 years. This study shows the challenges in making an etiologic diagnosis of CAP in pediatric population because of the poor concordance between tests and the high percentage of multiple microorganisms in healthy children. IS is useful for CAP diagnosis in pediatric population.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12887-022-03235-z.

Strengthening Tuberculosis Services for Children and Adolescents in Low Endemic Settings

In low tuberculosis-burden countries, children and adolescents with the highest incidence of tuberculosis (TB) infection or disease are usually those who have immigrated from high-burden countries. It is, therefore, essential that low-burden countries provide healthcare services to immigrant and refugee families, to assure that their children can receive proper testing, evaluation, and treatment for TB. Active case-finding through contact tracing is a critical element of TB prevention in children and in finding TB disease at an early, easily treated stage. Passive case-finding by evaluating an ill child is often delayed, as other, more common infections and conditions are suspected initially. While high-quality laboratory services to detect Mycobacterium tuberculosis are generally available, they are often underutilized in the diagnosis of childhood TB, further delaying diagnosis in some cases. Performing research on TB disease is difficult because of the low number of cases that are spread over many locales, but critical research on the evaluation and treatment of TB infection has been an important legacy of low-burden countries. The continued education of medical providers and the involvement of educational, professional, and non-governmental organizations is a key element of maintaining awareness of the presence of TB. This article provides the perspective from North America and Western Europe but is relevant to many low-endemic settings. TB in children and adolescents will persist in low-burden countries as long as it persists throughout the rest of the world, and these wealthy countries must increase their financial commitment to end TB everywhere.

Stool-based Xpert MTB/RIF Ultra assay as a tool for detecting pulmonary tuberculosis in children with abnormal chest imaging: A prospective cohort study

OBJECTIVES

To evaluate the diagnostic efficacy of stool-based Xpert MTB/RIF Ultra assay versus other assays for the detection of paediatric pulmonary tuberculosis (PTB).

METHODS

A prospective head-to-head comparative study was conducted from Dec 2017 to May 2019 in Shanghai Public Health Clinical Centre. Samples were collected from children (< 15 years) with abnormal chest imaging (X-ray or CT scan) results for the following tests: Ultra on stool sample (Ultra-Stool), Ultra on respiratory tract sample (Ultra-RTS), Xpert MTB/RIF assay (Xpert) on RTS (Xpert-RTS), acid-fast bacilli smear on RTS (AFB-RTS), and Mycobacterium tuberculosis (Mtb) culture on RTS (Culture-RTS). The results were compared with a composite reference standard.

RESULTS

A total of 126 cases with paired results were analysed. Against a composite reference standard, Ultra-RTS demonstrated the highest sensitivity (52%) and specificity (100%). Ultra-Stool showed 84.1% concordance with Ultra-RTS, demonstrating 45.5% sensitivity and 94.7% specificity (kappa = 0.65, 95% CI= 0.51-0.79). The sensitivity of Ultra-Stool was similar to Mtb culture (45.5%, p = 1.000) and higher than AFB-RTS (27.3%, p < 0.05). Assay positivity was associated with age and infiltration range in chest imaging.

CONCLUSIONS

When RTS is difficult to obtain, stool sample-based Ultra is a comparable alternative.

Advances in the diagnosis of pulmonary tuberculosis in children

Major challenges still exist in the accurate diagnosis of tuberculosis in children. Algorithms based on clinical and radiological features remain in widespread use despite poor performance. Newer molecular diagnostics allow for rapid identification of TB and detection of drug-resistance in a subset of children, but lack sensitivity. Molecular testing of multiple specimens, including non-traditional specimen types, such as nasopharyngeal aspirates and stool and urine, may improve sensitivity, but the optimal combination of specimens requires further research. Novel tests under development or evaluation include a urine lipoarabinomannan test with improved sensitivity and a range of biomarkers measured from stimulated or unstimulated peripheral blood.

Accuracy of Xpert Ultra in Diagnosis of Pulmonary Tuberculosis among Children in Uganda: a Substudy from the SHINE Trial

Childhood tuberculosis (TB) presents significant diagnostic challenges associated with paucibacillary disease and requires a more sensitive test. We evaluated the diagnostic accuracy of Xpert MTB/RIF Ultra (Ultra) compared to other microbiological tests using respiratory samples from Ugandan children in the SHINE trial. SHINE is a randomized trial evaluating shorter treatment in 1,204 children with minimal TB disease in Africa and India. Among 352 samples and one cervical lymph node fine needle aspirate, one sample was randomly selected per patient and tested with the Xpert MTB/RIF assay (Xpert) and with Lowenstein-Jensen medium (LJ) and liquid mycobacterial growth indicator tube (MGIT) cultures. We selected only uncontaminated stored sample pellets for Ultra testing. We estimated the sensitivity of Xpert and Ultra against culture and a composite microbiological reference standard (any positive result). Of 398 children, 353 (89%) had culture, Xpert, and Ultra results. The median age was 2.8 years (interquartile range [IQR], 1.3 to 5.3); 8.5% (30/353) were HIV infected, and 54.4% (192/353) were male. Of the 353, 31 (9%) were positive by LJ and/or MGIT culture, 36 (10%) by Ultra, and 16 (5%) by Xpert. Sensitivities (95% confidence intervals [CI]) were 58% (39 to 65% [18/31]) for Ultra and 45% (27 to 64% [14/31]) for Xpert against any culture-positive result, with false positives of <1% and 5.5% for Xpert and Ultra. Against a composite microbiological reference, sensitivities were 72% (58 to 84% [36/50]) for Ultra and 32% (20 to 47% [16/50]) for Xpert. However, there were 17 samples that were positive only with Ultra (majority trace). Among children screened for minimal TB in Uganda, Ultra has higher sensitivity than Xpert. This represents an important advance for a condition which has posed a diagnostic challenge for decades.

Caracterización de los pacientes menores de 15 años con tuberculosis en el Hospital Universitario San Vicente Fundación, 2011-2018

La Tuberculosis (TB) es la enfermedad infecciosa que más daño ha causado a la especie humana a lo largo de toda la historia, tanto por el número de enfermos como de muertos. Se ha calculado que en los últimos 200 años ha sido la responsable de la muerte de más de 1.000 millones de personas (1). La TB sigue siendo una de las enfermedades infecciosas más importante en esta época, y es el fiel reflejo de las enormes diferencias económicas y sociales que siguen existiendo en la población mundial1,2. Objetivo: describir las características demográficas y clínicas de los pacientes menores de 15 años con TB en el período 2011 – 2018 en un Hospital de cuarto nivel de la ciudad de Medellín – Colombia. Metodología: estudio observacional descriptivo de corte transversal. Incluyó pacientes menores de 15 años que asistieron al Hospital Universitario San Vicente Fundación (HUSVF) a quienes se les diagnosticó TB pulmonar y/o extrapulmonar, en el período comprendido entre enero de 2011 a diciembre de 2018. Resultados: 184 historias de pacientes con TB cumplieron los criterios de inclusión. Setenta y un pacientes (38.6 %) correspondían a TB pulmonar, 59 (32 %) a otras TB intratorácicas y 54 (29.3 %) a TB extrapulmonar. Las formas de TB más frecuentes fueron: ganglionar, del sistema nervioso central (SNC) y diseminada. De los niños menores de 5 años, el 50 % presentaron algún grado de desnutrición. La confirmación microbiológica por cultivo o baciloscopia (BK) estuvo presente en 91 pacientes (49.4 %) y por Reacción en Cadena de la Polimerasa (PCR) en 72 (39.1 %). Conclusiones: la TB infantil requiere un alto índice de sospecha. La suma de criterios es muy importante para su diagnóstico dada la fisiopatología de la enfermedad, sin embargo la búsqueda exhaustiva de la micobacteria es una estrategia útil para un tratamiento efectivo.

Improving pediatric TB diagnosis in North Kivu (DR Congo), focusing on a clinical algorithm including targeted Xpert MTB/RIF on gastric aspirates

Background

The incidence of tuberculosis (TB) in the Democratic Republic of the Congo (DRC) is 323/100,000. A context of civil conflict, internally displaced people and mining activities suggests a higher regional TB incidence in North Kivu. Médecins Sans Frontières (MSF) supports the General Reference Hospital of Masisi, North Kivu, covering a population of 520,000, with an elevated rate of pediatric malnutrition. In July 2017, an adapted MSF pediatric TB diagnostic algorithm, including Xpert MTB/RIF on gastric aspirates (GAs), was implemented. The aim of this study was to evaluate whether the introduction of this clinical pediatric TB diagnostic algorithm influenced the number of children started on TB treatment.

Methods

We performed a retrospective analysis of pediatric TB cases started on treatment in the inpatient therapeutic feeding centre (ITFC) and the pediatric ward. We compared data collected in the second half (July to December) of 2016 (before introduction of the new diagnostic algorithm) and the second half of 2017. For the outcome variables the difference between the two years was calculated by a Pearson Chi-square test.

Results

In 2017, 94 GAs were performed, compared to none in 2016. Twelve percent (11/94) of samples were Xpert MTB/RIF positive. Sixty-eight children (2.9% of total exits) aged between 3 months and 15 years started TB treatment in 2017, compared to 19 (1.4% of total exits) in 2016 (p 0.002). The largest increase in pediatric TB diagnoses in 2017 occurred in patients with a negative Xpert MTB/RIF result, but clinically highly suggestive of TB according to the newly introduced diagnostic algorithm. Fifty-two (3.1%) children under five years old started treatment in 2017, as compared to 14 (1.3%) in 2016 (p 0.004). The increase was less pronounced and not statistically significant in older patients: sixteen children (2.6%) above 5 years old started TB treatment in 2017 as compared to five (1.3%) in 2016 (p 0.17).

Conclusion

After the introduction of an adapted clinical pediatric TB diagnostic algorithm, including Xpert MTB/RIF on gastric aspirates, we observed a significant increase in the number of children – especially under 5 years old – started on TB treatment, mostly on clinical grounds. Increased ‘clinician awareness’ of pediatric TB likely played an important role.

Combined Use of Gastric Aspirate and Induced Sputum Increases the Microbiological Diagnosis of Tuberculosis in Children

Objective Diagnosis of pulmonary tuberculosis (PTB) in pediatrics is a challenge due to the paucibacillary condition of the disease in this population, low sputum expectoration, and diverse unspecific symptomatology. Mycobacterial isolation through culture remains a priority. The objective of this study is to explore gastric aspirates and induced sputum techniques in the pediatric population for positivity on mycobacterial cultures.

Methods In this observational analytical study, two temporal groups were evaluated. A comparison of the isolation rate defined as positive culture confirmation by gastric aspirate (GA), induced sputum (IS), or combination of these both techniques in children under 10 years of age. The study included 86 children, 37 in the first evaluated study group and 49 in the second group.

Discussion Culture positivity was 10.8 and 30.6% for the first and second case series, respectively. These findings showed that the combination of GA and IS in two consecutive days yielded a significantly higher detection rate to confirm pulmonary tuberculosis by culture.

Conclusion The combination of GA plus IS samples for collection of M. tuberculosis culture can be a useful, nonexpensive, and safe diagnostic tool in low- and middleincome countries to diagnose tuberculosis in children.

Specimen Pooling as a Diagnostic Strategy for Microbiologic Confirmation in Children with Intrathoracic Tuberculosis

Three-hundred four young children with suspected pulmonary tuberculosis had a gastric aspirate, induced sputum and nasopharyngeal aspirate collected on each of 2 consecutive weekdays. Specimens collected on the second day were pooled in the laboratory for each child individually. The diagnostic yield by Xpert and culture from pooled specimens was not significantly different to a single gastric aspirate.

Tuberculosis in Children

Mycobacterium tuberculosis is the leading cause of death worldwide from a single bacterial pathogen. The World Health Organization estimates that annually 1 million children have tuberculosis (TB) disease and many more harbor a latent form. Accurate estimates are hindered by under-recognition and challenges in diagnosis. To date, an accurate diagnostic test to confirm TB in children does not exist. Treatment is lengthy but outcomes are generally favorable with timely initiation. With the End TB Strategy, there is an urgent need for improved diagnostics and treatment to prevent the unnecessary morbidity and mortality from TB in children.

The Incremental Value of Repeated Induced Sputum and Gastric Aspirate Samples for the Diagnosis of Pulmonary Tuberculosis in Young Children With Acute Community-Acquired Pneumonia

Background.

Mycobacterium tuberculosis (Mtb) contributes to the pathogenesis of childhood acute community-acquired pneumonia in settings with a high tuberculosis burden. The incremental value of a repeated induced sputum (IS) sample, compared with a single IS or gastric aspirate (GA) sample, is not well known.

Methods.

Two IS samples were obtained for Mtb culture from children enrolled as cases in the Pneumonia Etiology Research for Child Health (PERCH) study in South Africa. Nonstudy attending physicians requested GA if pulmonary tuberculosis was clinically suspected. We compared the Mtb yield of 2 IS samples to that of 1 IS sample and GA samples.

Results

. Twenty-seven (3.0%) culture-confirmed pulmonary tuberculosis cases were identified among 906 children investigated with IS and GA samples for Mtb. Results from 2 IS samples were available for 719 children (79.4%). Of 12 culture-confirmed pulmonary tuberculosis cases identified among children with ≥2 IS samples, 4 (33.3%) were negative at the first IS sample. In head-to-head comparisons among children with both GA and IS samples collected, the yield of 1 GA sample (8 of 427; 1.9%) was similar to that of 1 IS sample (5 of 427, 1.2%), and the yield of 2 GA samples (10 of 300; 3.3%) was similar to that of 2 IS samples (5 of 300; 1.7%). IS samples identified 8 (42.1%) of the 19 culture-confirmed pulmonary tuberculosis cases that were identified through submission of IS and GA samples.

Conclusions.

A single IS sample underestimated the presence of Mtb in children hospitalized with severe or very severe pneumonia. Detection of Mtb is enhanced by combining 2 IS with GA sample collections in young children with acute severe pneumonia.

Bacteriological diagnosis of childhood TB: a prospective observational study

Childhood TB diagnosis is challenging. Studies in adults suggest Microscopic Observation Drug Susceptibility (MODS) culture or the Xpert MTB/RIF assay might be used to expand bacteriological diagnosis. However data from children are more limited. We prospectively compared MODS and Xpert MTB/RIF with standard microscopy and culture using the BD MGIT 960 system among 1442 Kenyan children with suspected TB. 97 specimens from 54 children were TB culture-positive: 91 (94%) by MGIT and 74 (76%) by MODS (p = 0.002). 72 (74%) culture-positive and 7 culture-negative specimens were Xpert MTB/RIF positive. Xpert MTB/RIF specificity was 100% (99.7–100%) among 1164 specimens from 892 children in whom TB was excluded, strongly suggesting all Xpert MTB/RIF positives are true positives. The sensitivity of MGIT, MODS and Xpert MTB/RIF was 88%, 71% and 76%, respectively, among all 104 true positive (culture and/or Xpert MTB/RIF positive) specimens. MGIT, MODS and Xpert MTB/RIF on the initial specimen identified 40/51 (78%), 33/51 (65%) and 33/51 (65%) culture-confirmed pulmonary TB cases, respectively; Xpert MTB/RIF detected 5 additional culture-negative cases. The high sensitivity and very high specificity of the Xpert MTB/RIF assay supports its inclusion in the reference standard for bacteriological diagnosis of childhood TB in research and clinical practice.

Tuberculosis in Children

Mycobacterium tuberculosis is the leading cause of death worldwide from a single bacterial pathogen. The World Health Organization estimates that annually 1 million children have tuberculosis (TB) disease and many more harbor a latent form. Accurate estimates are hindered by under-recognition and challenges in diagnosis. To date, an accurate diagnostic test to confirm TB in children does not exist. Treatment is lengthy but outcomes are generally favorable with timely initiation. With the End TB Strategy, there is an urgent need for improved diagnostics and treatment to prevent the unnecessary morbidity and mortality from TB in children.

Nontuberculous mycobacteria in gastrostomy fed patients with cystic fibrosis

Multi-drug resistant Mycobacterium abscessus complex (MABSC) is a form of Nontuberculous mycobacteria (NTM) of special, international concern in Cystic Fibrosis (CF). We hypothesised that gastric juice and percutaneous endoscopic gastrostomy (PEG) feeding devices might yield MABSC isolates. Gastric juice and sputa from sixteen adult PEG fed CF patients and five replaced PEG tubes were studied. Bacterial and fungal isolates were cultured. Mycobacterium were identified by rpoB, sodA and hsp65 gene sequencing and strain typed using variable number tandem repeat. Bacteria and/or fungi grew from all gastric juice, sputa and PEG samples. MABSC were detected in 7 patients. Five had MABSC in their sputum. Two had an identical MABSC strain in their sputum and gastric juice and one had the same strain isolated from their PEG tube and sputum. Two patients who were sputum sample negative had MABSC isolated in their gastric juice or PEG tube. MABSC were therefore identified for the first time from a gastric sample in a minority of patients. We conclude that gastric juice and PEG-tubes may be a potential source of MABSC isolates in CF patients, and these findings warrant further study.

Official American Thoracic Society/Infectious Diseases Society of America/Centers for Disease Control and Prevention Clinical Practice Guidelines: Diagnosis of Tuberculosis in Adults and Children

BACKGROUND

Individuals infected with Mycobacterium tuberculosis (Mtb) may develop symptoms and signs of disease (tuberculosis disease) or may have no clinical evidence of disease (latent tuberculosis infection [LTBI]). Tuberculosis disease is a leading cause of infectious disease morbidity and mortality worldwide, yet many questions related to its diagnosis remain.

METHODS

A task force supported by the American Thoracic Society, Centers for Disease Control and Prevention, and Infectious Diseases Society of America searched, selected, and synthesized relevant evidence. The evidence was then used as the basis for recommendations about the diagnosis of tuberculosis disease and LTBI in adults and children. The recommendations were formulated, written, and graded using the Grading, Recommendations, Assessment, Development and Evaluation (GRADE) approach.

RESULTS

Twenty-three evidence-based recommendations about diagnostic testing for latent tuberculosis infection, pulmonary tuberculosis, and extrapulmonary tuberculosis are provided. Six of the recommendations are strong, whereas the remaining 17 are conditional.

CONCLUSIONS

These guidelines are not intended to impose a standard of care. They provide the basis for rational decisions in the diagnosis of tuberculosis in the context of the existing evidence. No guidelines can take into account all of the often compelling unique individual clinical circumstances.

Recommendations for the diagnosis of pediatric tuberculosis

Tuberculosis (TB) is still the world's second most frequent cause of death due to infectious diseases after HIV infection, and this has aroused greater interest in identifying and managing exposed subjects, whether they are simply infected or have developed one of the clinical variants of the disease. Unfortunately, not even the latest laboratory techniques are always successful in identifying affected children because they are more likely to have negative cultures and tuberculin skin test results, equivocal chest X-ray findings, and atypical clinical manifestations than adults. Furthermore, they are at greater risk of progressing from infection to active disease, particularly if they are very young. Consequently, pediatricians have to use different diagnostic strategies that specifically address the needs of children. This document describes the recommendations of a group of scientific societies concerning the signs and symptoms suggesting pediatric TB, and the diagnostic approach towards children with suspected disease.

Laboratory Diagnosis of Mycobacterium tuberculosis Infection and Disease in Children

Diagnosis of tuberculosis in children is challenging; even with advanced technologies, the diagnosis is often difficult to confirm microbiologically in part due to the paucibacillary nature of the disease. Clinical diagnosis lacks standardization, and traditional and molecular microbiologic methods lack sensitivity, particularly in children. Immunodiagnostic tests may improve sensitivity, but these tests cannot distinguish tuberculosis disease from latent infection and some lack specificity. While molecular tools like Xpert MTB/RIF have advanced our ability to detect Mycobacterium tuberculosis and to determine antimicrobial resistance, decades old technologies remain the standard in most locales. Today, the battle against this ancient disease still poses one of the primary diagnostic challenges in pediatric laboratory medicine.

Extensively drug-resistant tuberculosis in a young child after travel to India

Extensively drug-resistant (XDR) tuberculosis is becoming increasingly prevalent worldwide, but little is known about XDR tuberculosis in young children. In this Grand Round we describe a 2-year-old child from the USA who developed pneumonia after a 3 month visit to India. Symptoms resolved with empirical first-line tuberculosis treatment; however, a XDR strain of Mycobacterium tuberculosis grew in culture. In the absence of clinical or microbiological markers, low-radiation exposure pulmonary CT imaging was used to monitor treatment response, and guide an individualised drug regimen. Management was complicated by delays in diagnosis, uncertainties about drug selection, and a scarcity of child-friendly formulations. Treatment has been successful so far, and the child is in remission. This report of XDR tuberculosis in a young child in the USA highlights the risks of acquiring drug-resistant tuberculosis overseas, and the unique challenges in management of tuberculosis in this susceptible population.

The Role of Clinical Symptoms in the Diagnosis of Intrathoracic Tuberculosis in Young Children

BACKGROUND

Childhood tuberculosis (TB) is usually Mycobacterium tuberculosis (MTB) culture negative. Furthermore, clinical presentation may be altered by active case finding, isoniazid prophylaxis and early treatment. We aimed to establish the value of presenting symptoms for intrathoracic TB case diagnosis among young children.

METHODS

Healthy, HIV-uninfected, South African infants in an efficacy trial of a novel TB vaccine (MVA85A) were followed for 2 years for suspected TB. When suspected, investigation followed a standardized algorithm comprising symptom history, QuantiFERON Gold-in-Tube, chest radiography (CXR), MTB culture and Xpert MTB/RIF from paired gastric lavage and induced sputa. Adjusted odds ratios and 95% confidence intervals describe the associations between symptoms and positive MTB culture or Xpert MTB/RIF, and CXR compatible with intrathoracic TB.

RESULTS

Persistent cough was present in 172/1017 (16.9%) of the children investigated for TB. MTB culture/Xpert MTB/RIF was positive in 38/1017 children (3.7%); and CXR was positive, that is, compatible with intrathoracic TB, in 131/1017 children (12.9%). Children with persistent cough had more than triple the odds of a positive MTB culture/Xpert MTB/RIF (adjusted odds ratios: 3.3, 95% confidence interval: 1.5-7.0) and positive CXR (adjusted odds ratios: 3.5, 95% confidence interval: 2.2-5.5). Persistent cough was the only symptom that differentiated children with severe (56.5%) from nonsevere intrathoracic TB disease (28.2%; P = 0.001).

CONCLUSION

Persistent cough was the cardinal diagnostic symptom associated with microbiologic and radiologic evidence, and disease severity, of intrathoracic TB. Symptom-based definitions of TB disease for diagnostic, preventive and therapeutic studies should prioritize persistent cough above other symptoms compatible with childhood TB.

Newer Diagnostic Tests for Pulmonary Tuberculosis in Children

It has been well recognized that the diagnosis of pulmonary tuberculosis in children is often compromised by non-specific symptoms, paucibacillary nature of the disease, and the difficulty in collecting the specimen. Consequently, most tuberculosis cases in children are not confirmed, due to which the estimation of the global burden of tuberculosis in children may be inaccurate. There has also been a common misperception that diagnosis of tuberculosis and collecting respiratory specimen in children is always difficult. Because of this, microbiological confirmation of tuberculosis in young children is not routinely attempted in most endemic areas. With the emergence of HIV-related tuberculosis disease and drug-resistant tuberculosis, the availability of accurate, rapid and child friendly diagnostic tools to identify Mycobacterium tuberculosis in respiratory specimen are urgently required in endemic settings. There have been a large number of studies evaluating new diagnostic tests for tuberculosis in the past decade, but few have been evaluated in children. This review will address the developments in respiratory specimen collection and laboratory diagnostic tests of tuberculosis, with a focus on those that have been evaluated in children.

Diagnostic yield and safety of sputum induction with nebulized racemic salbutamol versus hypertonic saline in smear-negative pulmonary tuberculosis

OBJECTIVES

The aim of the study was to compare the diagnostic yield and safety profile of sputum induction (SI) with nebulized racemic salbutamol solution versus hypertonic saline in smear-negative pulmonary tuberculosis (TB).

METHODS

The prospective study was conducted at Songklanagarind Hospital, Thailand. Suspected smear-negative pulmonary TB cases were recruited and randomized to receive SI with either nebulized racemic salbutamol solution or 3% sodium chloride (NaCl) solution. Induced sputum was examined with the acid-fast bacilli (AFB) smear test and cultured for Mycobacterium tuberculosis. The efficacy and adverse events of SI were analyzed.

RESULTS

A total of 59 patients received SI with nebulized racemic salbutamol solution and 53 received 3% NaCl solution. There was no significant difference between the two groups in the average quantity of induced sputum (1.3 ± 0.1 versus 1.2 ± 0.2 ml, p = 0.5). The percentages of positive AFB smear and TB cultures in the salbutamol group were 15% and 22%, and 13% and 17% in the 3% NaCl group (p = 0.5), respectively. Racemic salbutamol solution could increase the TB diagnostic yield similarly to 3% NaCl, but incurred less chest tightness (5% versus 15%) and bronchospasm (0% versus 11.3%, p = 0.02) compared with 3% NaCl.

CONCLUSIONS

SI by nebulized racemic salbutamol solution offers equal benefits to 3% NaCl solution in increasing both sputum quantity and diagnostic yield in smear-negative patients suspected of having pulmonary TB. Nebulized racemic salbutamol does not produce bronchospasm and chest tightness occurs less frequently than with 3% NaCl. Therefore, SI with nebulized racemic salbutamol solution should be considered as a good alternative noninvasive diagnostic tool for the diagnosis of pulmonary TB when hypertonic saline is unavailable or contraindicated.

Evaluation of Microscopic Observation Drug Susceptibility (MODS) and the string test for rapid diagnosis of pulmonary tuberculosis in HIV/AIDS patients in Bolivia

BACKGROUND

Tuberculosis (TB) is the most common opportunistic infection and the leading cause of death in HIV-positive people worldwide. Diagnosing TB is difficult, and is more challenging in resource-scarce settings where culture-based diagnostic methods rely on poorly sensitive smear microscopy by Ziehl-Neelsen stain (ZN).

METHODS

We performed a cross-sectional study examining the diagnostic utility of Microscopic Observation Drug Susceptibility liquid culture (MODS) versus traditional Ziehl-Neelsen staining (ZN) and Lowenstein Jensen culture (LJ) of pulmonary tuberculosis (TB) and multidrug-resistant tuberculosis (MDRTB) in HIV-infected patients in Bolivia. For sputum scarce individuals we assessed the value of the string test and induced sputum for TB diagnosis. The presence of Mycobacterium tuberculosis (Mtb) in the sputum of 107 HIV-positive patients was evaluated by ZN, LJ, and MODS. Gastric secretion samples obtained by the string test were evaluated by MODS in 102 patients.

RESULTS

The TB-HIV co-infection rate of HIV patients with respiratory symptoms by sputum sample was 45 % (48/107); 46/48 (96 %) were positive by MODS, 38/48 (79 %) by LJ, and 30/48 (63 %) by ZN. The rate of MDRTB was 9 % (4/48). Median time to positive culture was 10 days by MODS versus 34 days by LJ (p < 0.0001). In smear-negative patients, MODS detected TB in 17/18 patients, compared to 11/18 by LJ (94.4 % vs 61.0 %, p = 0.03 %). In patients unable to produce a sputum sample without induction, the string test cultured by MODS yielded Mtb in of 9/11 (82 %) TB positive patients compared to 11/11 (100 %) with induced sputum. Of the 10 patients unable to produce a sputum sample, 4 were TB-positive by string test.

CONCLUSION

MODS was faster and had a higher Mtb detection yield compared to LJ, with a greater difference in yield between the two in smear-negative patients. The string test is a valuable diagnostic technique for HIV sputum-scarce or sputum-absent patients, and should be considered as an alternative test to induced sputum to obtain sample for Mtb in resource-limited settings. Nine percent of our TB+ patients had MDRTB, which reinforces the need for rapid detection with direct drug susceptibility testing in HIV patients in Bolivia.

What steps do we need to take to improve diagnosis of tuberculosis in children?

Tuberculosis still represents a big global public health challenge. The diagnosis of tuberculosis and the differentiation between active and latent tuberculosis remain difficult, particularly in childhood, because of the lack of a gold standard test for diagnosis. In the last decade, novel diagnostic assays have been developed. Among immunologic tests, new assays based on the measurement of different cytokines released by specific T cells in response to Mycobacterium tuberculosis antigens, other than INF-γ, have been investigated. Promising results rely on nucleic acid amplification techniques, also able to detect drugs resistance. Innovative research fields studied the modifications of CD27 expression in T cells as well as different host gene expression in response to M. tuberculosis. Further studies are needed to assess the diagnostic value and the accuracy of these new assays.

Induced sputum is safe and well-tolerated for TB diagnosis in a resource-poor primary healthcare setting

Improved tuberculosis (TB) diagnostics are required. Induced sputum sampling is superior to spontaneous sputum analysis for diagnosis of pulmonary TB. Therefore, we examined the applicability of induced sputum in primary health centers of the Peruvian TB program and studied the safety and tolerability of this procedure. We show that induced sputum is safe, inexpensive, and well-tolerated in a resource-limited environment. Widespread use of induced sputum at primary health centers can be implemented and may improve TB diagnosis.

A controlled trial of sputum induction and routine collection methods for TB diagnosis in a South African community

The diagnostic yield of pulmonary tuberculosis (TB) by sputum induction (SI) at the first point of contact with health services, conducted in all patients with suspected TB regardless of the ability to expectorate spontaneously, has not been evaluated. We compared the diagnostic yield of SI to routine sputum collection in a South African community setting. Ambulatory patients with suspected TB provided a 'spot' expectorated sputum sample, an SI sample by hypertonic (5 %) saline nebulization, and early morning expectorated sputum sample. The diagnostic yield of sputum smear microscopy and liquid culture (denominator all subjects with any positive Mycobacterium tuberculosis culture), and time-to-positivity of culture were compared between SI and expectorated samples. A total of 555 subjects completed the SI procedure, of whom 132 (24 %) were human immunodeficiency virus (HIV)-infected. One hundred and twenty-nine samples (129, 23 %) were M. tuberculosis culture-positive. The time-to-positivity of Mycobacteria Growth Indicator Tube (MGIT) culture was shorter for SI (median difference 2 days, p = 0.63) and for early morning expectorated sputum (median difference 2 days, p = 0.02) compared to spot expectorated sputum. However, there was no difference in the culture-positive diagnostic yield between SI and spot expectorated sputum [difference +0.7 %; confidence interval (CI) -7.0 to +8.5 %, p = 0.82] or SI and early morning expectorated sputum (difference +4.7 %; CI -3.2 to +12.5 %, p = 0.20) for all subjects or for HIV-infected subjects. SI reduces the time to positive M. tuberculosis culture, but does not increase the rate of positive culture compared to routine expectorated sputum collection. SI cannot be recommended as the routine collection method at first contact among ambulatory patients with suspected TB in high-burden communities.

Use of Induced sputum to determine the prevalence of Pneumocystis jirovecii in immunocompromised children with pneumonia

BACKGROUND

Information on prevalence of Pneumocystis jirovecii pneumonia (PCP) in immunocompromised children with pneumonia in Southeast Asia is limited.

METHODS

Immunocompromised children hospitalized with radiographic pneumonia were investigated for PCP by testing induced sputum by using polymerase chain reaction (PCR).

RESULTS

Ninety-four immunocompromised children (mean age 74.5 ± 43.7 months, boys 69) with pneumonia were investigated for PCP. Underlying disease included solid tumors and hematological malignancy in 57, HIV infection in 14, primary immune deficiency in 11 and other immune deficiency disorders in 12 children. PCR could detect P. jirovecii in 14 children. Prevalence of PCP in HIV-infected children was 43% (6 of 14), renal disease on immunosuppressants 45% (4 of 9), primary immune deficiency 19% (2 of 11) and malignancies on chemotherapy 4% (2 of 57). Three of 14 children died from PCP.

CONCLUSIONS

PCP is responsible for pneumonia in 14% of children with underlying immunocompromised state; PCR on induced sputum improves diagnosis.

Childhood tuberculosis in northern Viet Nam: a review of 103 cases

Background

Childhood tuberculosis causes significant morbidity and mortality in Southeast Asia, yet little is known about the epidemiology and clinical characteristics of this disease in Viet Nam.

Objectives

To determine the demographics, clinical presentations, radiographic and microbiologic findings, treatment regimens, and outcomes of children admitted with tuberculosis (TB) to a national referral hospital in Viet Nam.

Methods

We conducted a retrospective case series study of children ≤ 15 years old with bacteriologically confirmed or clinically diagnosed TB admitted to a national referral hospital in Ha Noi, Viet Nam from January through December 2007.

Results

One hundred three children were identified: median age 5 years (IQR 2-10), 44% female, 99% Kinh ethnicity, 27% residing in Ha Noi, 88% with BCG vaccination, 27% with known TB contact, and 38% malnourished. Intrathoracic TB was present in 62%, extrathoracic in 52%, both intra and extrathoracic in 19%, and undetermined site in 5%. The most common extrathoracic manifestation was peripheral lymphadenitis, and children under 5 were more likely to have miliary TB or both intra and extrathoracic TB. Fever and failure to thrive were common presenting symptoms among all participants (65% and 56%, respectively), 66% of those with intrathoracic TB presented with cough, and 92% of those with TB meningitis presented with severe neurologic impairment. Acid-fast bacilli smears and mycobacterial cultures were positive in 18% and 21% of children tested, and histopathology was positive in 88% of those biopsied. There were no adverse drug reactions necessitating change in therapy, and no inpatient mortality.

Conclusions

Extrathoracic TB was common, treatment well tolerated and clinical outcomes excellent. Culture confirmation rates were low and emphasize the need for improved diagnostics.

Diagnosis of paediatric tuberculosis using sputum induction in Botswana: programme description and findings

SETTING

Four public hospitals in Botswana, a high tuberculosis (TB) burden setting.

OBJECTIVES

To assess the feasibility and utility of sputum induction in the diagnosis of paediatric TB.

DESIGN

From 2008 to 2010, children aged ≤18 years referred for suspected pulmonary TB underwent sputum induction. Confirmed TB was defined as the presence of at least one of the signs and symptoms suggestive of TB and positive Mycobacterium tuberculosis culture. Information on TB-associated symptoms (cough, fatigue, night sweats, low appetite, chest pain, weight loss, haemoptysis and contact with a TB case) was collected for three risk groups: human immunodeficiency virus (HIV) positive children, HIV-negative children aged <3 years and HIV-negative children aged ≥3 years.

RESULTS

The median age of the 1394 subjects who underwent sputum induction was 3.8 years (IQR 1.3-8.4); 373 (27%) were HIV-positive, 419 (30%) were HIV-negative and 602 (43%) had unknown HIV status. TB was confirmed in 84 (6.0%); cases were more likely to have weight loss, chest pain or TB household contacts. There were no serious complications attributable to sputum induction during and after the procedure; only 0.8% (9/1174) of patients reported minor complications.

CONCLUSIONS

In Botswana, paediatric sputum induction was feasible, safe and assisted bacteriological confirmation in a subgroup of children treated for TB.

Intensified specimen collection to improve tuberculosis diagnosis in children from Rural South Africa, an observational study

BACKGROUND

In drug-resistant TB settings, specimen collection is critical for drug-susceptibility testing (DST). This observational study included multiple specimen types collected from pediatric TB suspects with the aim to determine diagnostic yield and inform clinical practice in children with drug-resistant and drug-susceptible TB.

METHODS

From 03/2009-07/2010, TB suspects aged ≥6 months and ≤12 years were recruited among outpatient and inpatient settings. Subjects were new TB suspects or had persistent symptoms despite ≥2 months of TB treatment. The protocol included collection of a single blood and urine specimen, a single sputum induction and, if inpatients and <5 years of age, collection of 3 gastric aspirates (GA). Samples were cultured on solid and/or liquid media. DST was by 1% proportion method.

RESULTS

Among 118 children with possible, probable or confirmed TB, the mean age was 4.9 years [SD 3.2] and 64 (62%) of those tested were HIV-positive. Eight (7%) subjects were culture-positive from at least one specimen; yield did not differ by HIV status or TB treatment history. Among those with positive cultures, 7/8 (88%) were from induced sputum, 5/6 (83%) from GA, 3/8 (38%) from blood, and 3/7 (43%) from urine. In subjects with both induced sputum and GA collection, sputum provided one additional case compared to GA. Multidrug resistant (MDR)-TB was detected by urine culture alone in one child >5 years old. Pan-resistant extensively drug resistant (XDR)-TB was identified by cultures from all sites in one subject.

CONCLUSIONS

TB was cultured from HIV-positive and -negative children, and allowed for identification of MDR and XDR-TB cases. Urine and induced sputum each provided an additional TB diagnosis and, when compared to GA, may be considered a less invasive, same-day method of specimen collection for childhood TB suspects. This study illustrates the continued challenges and limitations of available strategies for pediatric TB diagnostics.

"Induced sputum versus gastric lavage for the diagnosis of pulmonary tuberculosis in children"

Background

Diagnosis of pulmonary tuberculosis (PTB) is difficult in infants and young children. For microbiological confirmation of PTB children, sequential gastric lavage (GL) is recommended. Induced sputum (IS) may be an alternative or complementary tool, but the information is limited in children in developed countries. The aim of this study is to assess the safety and diagnostic yield from IS combined with GL for PTB diagnosis in non-HIV infected children.

Methods

The study involved 22 children with suspected PTB admitted to the Getafe Hospital from January 2007 to May 2011. IS and GL were performed on three consecutive days, according to a standardized protocol. In all samples, BK staining, culture and PCR were carried out, including Genotype MTBDR plus for resistance to INH-RIF (Isoniazid-Rifampin) since 2008. A preliminary analysis of an ongoing prospective study is presented.

Results

Median age was 72 months (range 1 month to 14 years of age). Seven (33%) were ≤ 5 years of age. Seventeen were clinically diagnosed of PTB based on positive PPD and radiological criteria. Microbiological confirmation was achieved in 10 (58.8%) by either GL or IS. M. tuberculosis was identified by GL in 8 children (47.1%) and by IS in 7 (41.2%). One infant (2 IS samples) had transient oxygen desaturation recovered spontaneously.

Conclusions

IS appears to be safe and well tolerated by children for diagnosis of PTB and is more convenient. Increasing the diagnostic yield of PTB in children with PTB may be a complementary technique. Largest studies are necessary to define the role of IS in paediatric PTB.

The burden and outcomes of childhood tuberculosis in Cotonou, Benin

SETTING

The National Tuberculosis Programme (NTP) and the paediatric ward of the General Hospital (GH), Cotonou, Benin.

OBJECTIVE

To describe the burden of tuberculosis (TB), characteristics and outcomes among children treated in Cotonou from 2009 to 2011.

DESIGN

Cross-sectional cohort study consisting of a retrospective record review of all children with TB aged <15 years.

RESULTS

From 2009 to 2011, 182 children with TB were diagnosed and treated (4.5% of total cases), 153 (84%) by the NTP and 29 (16%) by the GH; the latter were not notified to the NTP. The incidence rate of notified TB cases was between 8 and 13 per 100 000 population, and was higher in children aged >5 years. Of 167 children tested, 29% were HIV-positive. Treatment success was 72% overall, with success rates of 86%, 62% and 74%, respectively, among sputum smear-positive, sputum smear-negative and extra-pulmonary patients. Treatment success rates were lower in children with sputum smear-negative TB (62%) and those with HIV infection (58%).

CONCLUSION

The number of children being treated for TB is low, and younger children in particular are underdiagnosed. There is a need to improve the diagnosis of childhood TB, especially among younger children, and to improve treatment outcomes among HIV-TB infected children, with better follow-up and monitoring.

Sputum induction to aid diagnosis of smear-negative or sputum-scarce tuberculosis in adults in HIV-endemic settings

Sputum induction can aid tuberculosis (TB) diagnosis, but adult data from HIV-endemic environments are limited, and it is unclear how performance varies depending on the clinical context (in-patient versus outpatient), HIV status and whether patients are smear-negative or sputum-scarce. 696 adults with suspected smear-negative or sputum-scarce TB from Cape Town (South Africa) were referred for routine sputum induction. Liquid culture for Mycobacterium tuberculosis served as the reference standard. 82% (573 out of 696) of patients provided a specimen ≥1 mL, 83% (231 out of 278) of which were of adequate quality. 15% (96 out of 652) of sputum induction specimens were culture-positive, and this yield was higher among inpatients versus outpatients (17% (71 out of 408) versus 10% (25 out of 244), p=0.01) and HIV-infected versus uninfected patients (17% (51 out of 294) versus 9% (16 out of 173), p=0.02), but similar for CD4 (>200 versus ≤200 cells·μL(-1)) and patient (smear-negative versus sputum-scarce) subcategories. Overall sensitivity (95% CI) of smear-microscopy was 49% (39-59%), higher among in-patients versus outpatients (55% (43-67%) versus 32% (14-50%), p=0.05), but unaffected by HIV co-infection, CD4 count or patient type. 29% (203 out of 696) of patients commenced anti-TB treatment and sputum induction offered microbiological confirmation and susceptibility testing in only 47% (96 out of 203). Under programmatic conditions in an HIV-endemic environment although the yield of culture was approximately two-fold higher amongst HIV-infected patients and inpatients, a fifth of all patients were unable to provide a specimen following sputum induction. Same-day microbiological diagnosis was only possible in ~50% of patients.

Promising directions in the diagnosis of childhood tuberculosis

Estimates of the burden of childhood tuberculosis have been hampered by the lack of a reliable diagnostic test. Clinical scoring systems, radiological findings and tuberculin skin testing (the traditional methods used for diagnosis) are unreliable, particularly in the era of HIV. Microbiologic confirmation using induced sputum is feasible and has become increasingly important to define the burden of disease and to enable appropriate treatment. The availability of a rapid molecular diagnostic test (Xpert® MTB/RIF; Cepheid) is an important advance that can improve case detection in children and enable rapid detection of mycobacterial drug resistance. Xpert testing of two induced sputum specimens detected approximately 75% of children with culture-confirmed disease. Urine lipoarabinomannan has shown promise as a rapid diagnostic in a subgroup of HIV-infected severely immunocompromised adults, but there have been no data in children so far. Further research is needed to develop a rapid point-of-care, reliable and affordable diagnostic test for childhood tuberculosis that can be widely used.

Description of pediatric tuberculosis evaluated in a referral center in istanbul Turkey

PURPOSE

Diagnosis of tuberculosis (TB) in children is more challenging than in adults. This study aimed to describe demographical, clinical and laboratory findings of children diagnosed with tuberculosis in Turkey, including the issues of contact tracing, culture positivity and forms of the disease.

MATERIALS AND METHODS

Clinical and laboratory data of 51 children with a mean age of 8.0±4.6 years who were diagnosed with TB were retrospectively reviewed. Main diagnostic tools included tuberculin skin test, chest X-ray, sputum/gastric aspirate culture with sensitivity testing, and direct microscopy for acid-fast bacilli on available samples. Clinical characteristics and outcomes of the patients were examined.

RESULTS

Thirty-six (70.6%) children were diagnosed with intra-thoracic and 15 (29.4%) with extra-thoracic tuberculosis. Twenty-eight of the patients had a positive Bacillus Calmette-Guérin vaccine scar (28/51, 54.9%) and 23/51 (45.1%) had a positive tuberculin skin test. An adult TB contact was identified in 27 (52.9%) of the cases. On direct microscopy, acid-fast bacilli were found in nine (17.6%) patients and positive culture for Mycobacterium tuberculosis was found in 19 (37.3%). Drug resistance to isoniazid was detected in four (7.8%). One patient with nephrotic syndrome and miliary tuberculosis died during follow-up. All other patients responded well to the treatment.

CONCLUSION

Focusing on active contact tracing among all household contacts of tuberculous cases may be helpful in early identification and controlling childhood disease, even in regions with low disease prevalence. Adopting a suspicious and proactive approach in this particular age group is warranted.

Tuberculosis diagnostics for children in high-burden countries: what is available and what is needed

BACKGROUND

The diagnosis of childhood tuberculosis (TB) is complex and most of the new diagnostics for TB are for adults.

AIMS

To review the performance of TB diagnostics and their suitability to its characteristics in young children.

METHODS

Expert opinion and review of the literature.

MAIN FINDINGS

The lack of a sufficient number of research studies on TB diagnostics for children hinders the preparation of systematic literature reviews. Information on test performance in children is often extrapolated from studies in adults and there is a dearth of evidence of test performance in children. Approaches to shorten the time required for diagnosis (by using a variety of specimens) are needed and there is preliminary evidence that such schemes are feasible. Diagnostics based on smear microscopy such as LED-FM, serological tests and IGRAS are unlikely to improve the diagnosis of active TB in children. Liquid and the MODS culture methods are more sensitive than solid culture, and new methods to detect mycobacterium nucleic acid or its components such as TrDNA fragments, LAMP assays and Xpert MTB/RIF have good potential to increase the number of cases confirmed. These tests should be evaluated in specimens which are easily accessible in children such as fine-needle aspiration biopsy, urine, blood and stools.

INTERPRETATION

The evaluation of new diagnostic tests for TB in children is overdue. The lack of suitable diagnostic tests hinders the proper management of children, the assessment of the real burden of childhood TB, evaluation of the efficacy of new treatments and vaccines and, ultimately, the development of effective control interventions.

Diagnosis and management of TB in children: an update

In recent years, several notable modifications have occurred in the management of TB infection and disease in children. First, we review new data related to infection, including alternative regimens for the treatment of latent TB, management of drug-resistant infection and preventive therapy in the context of HIV infection. Next, we summarize updated WHO guidelines for the treatment of TB in children, explore issues specific to the management of disease in HIV-infected children, and retreatment of TB, and review pediatric recommendations for the management of drug-resistant TB. Finally, we conclude with a discussion of adjunctive therapy and new drugs in development.

Increased and expedited case detection by Xpert MTB/RIF assay in childhood tuberculosis: a prospective cohort study

BACKGROUND

Diagnosis and timely treatment of tuberculosis in children is hampered by the absence of fast and reliable tests, especially in the era of human immunodeficiency virus (HIV). The aim of this study was to evaluate the diagnostic performance of the Xpert MTB/RIF assay (Xpert) in children with suspected tuberculosis in a high tuberculosis/HIV-burden setting.

METHODS

In a prospective study with a minimum follow-up of 12 months, 164 children with suspected tuberculosis were assigned to predefined diagnostic subgroups, based on microbiological and clinical findings. Results of smear microscopy and culture were compared against diagnostic performance of Xpert.

RESULTS

Twenty-eight of 164 children (17.1%) had confirmed tuberculosis. Xpert detected 100% (95% confidence interval [CI], 59.0%-100%) of smear-positive cases and 66.6% (95% CI, 43.0%-85.4%) of culture-positive but smear-negative cases. In the per-sample analysis, Xpert displayed a similar sensitivity (54.7% [95% CI, 42.7%-66.2%]) compared with culture methods. Xpert detected 3-fold more confirmed tuberculosis cases than smear microscopy but with equal rapidity. Four additional cases (8.5%) with clinical tuberculosis but negative culture were diagnosed by Xpert. Testing second and third samples increased sensitivity by 20% and an additional 16%, respectively. When tuberculosis was reliably excluded, Xpert's specificity was 100%. HIV infection did not affect diagnostic accuracy of Xpert.

CONCLUSIONS

Xpert was easy to perform and displayed similar diagnostic accuracy as culture methods in children with suspected tuberculosis. Rapid turnaround times should reduce treatment delay and improve patient outcome, although sensitivity remains suboptimal and access is dependent on local laboratory infrastructure.

Advances in the diagnosis of pulmonary tuberculosis in HIV-infected and HIV-uninfected children

The identification of improved diagnostic tests for tuberculosis has been identified as a global research priority. Over the past decade, there has been renewed interest in the development and validation of novel diagnostic tools for pulmonary tuberculosis that are applicable to resource-poor settings. These techniques are aimed primarily at improving detection of the organism or a specific host immune response. Although most studies have focused on determining the accuracy of novel tests in adults, it is likely they will also have the capacity to significantly improve the diagnosis of childhood tuberculosis. Improving the quality of clinical samples obtained from children with suspected tuberculosis remains an important research priority while awaiting validation of novel diagnostic tests. This review will focus on a number of recent developments for the diagnosis of tuberculosis, with a specific emphasis on the application of these new tests to children in settings where tuberculosis is endemic.

Consensus statement on diagnostic end points for infant tuberculosis vaccine trials

BACKGROUND

 Definition of clinical trial end points for childhood tuberculosis is hindered by lack of a standard case definition. We aimed to identify areas of consensus or debate on potential end points for tuberculosis vaccine trials among human immunodeficiency virus-uninfected children.

METHODS

 Thirty-eight opinion leaders participated in a Consensus Workshop at the Second Global Forum on TB Vaccines (Estonia, 2010). Outcomes were categorized as unanimity, modified consensus, or lack of consensus. Individual reservations were noted.

RESULTS

 Modified consensus was achieved on 3 issues: (1) unsuitability of historical BCG trial end points as sole primary end points for modern infant trials; (2) symptomatic, complicated intrathoracic tuberculosis as an uncommon but clinically relevant disease phenotype; (3) primary complex tuberculosis in younger children as a common, high-risk phenotype, with a high rate of spontaneous resolution. Participants agreed that radiologic diagnosis of intrathoracic tuberculosis would be based primarily on hilar lymphadenopathy. Lack of consensus was noted for (1) significance of isolated culture of Mycobacterium tuberculosis and (2) the need for evidence of prior tuberculosis exposure to support a diagnosis of tuberculosis disease. Reservations were expressed regarding use of interferon-γ release assays and the clinical relevance, and potential for misclassification, of primary complex tuberculosis.

CONCLUSIONS

 The Workshop did not achieve consensus on a single primary end-point definition. Tuberculosis disease phenotypes with optimal diagnostic certainty will be uncommon in the study population. Criteria for composite or multiple end points were identified, and we propose a hierarchy of end-point criteria, based on rate of occurrence, clinical relevance, and diagnostic certainty.

Sputum induction for the diagnosis of pulmonary tuberculosis: a systematic review and meta-analysis

Sputum induction (SI) has been proposed as the optimal sample collection method for patients with paucibacillary tuberculosis (TB). Studies reporting the culture of Mycobacterium tuberculosis from SI were reviewed. A random-effects meta-analysis of diagnostic yield (numerator M. tuberculosis SI culture-positive cases; denominator all culture-positive cases) was conducted. Diagnostic yields (95% confidence intervals, CIs) were displayed as Forest plots. Heterogeneity was evaluated using Chi-squared and I-squared tests and meta-regression analysis. Ninety publications were screened, 28 full-text papers reviewed, and 17 analyzed. Collectively, n=627 SI culture-positive cases among n=975 culture-confirmed TB cases were reported. The diagnostic yield of SI ranged from 35 to 95%. The pooled diagnostic yield was 74% (CI 65-81%), with significant heterogeneity (p<0.0001, I2=86%). There were no statistically significant differences in the yield between sub-groups defined by human immunodeficiency virus (HIV) prevalence or age. Univariate analysis demonstrated that the use of fiberoptic bronchoscopy (FOB) as the comparator method was associated with a 22% reduction (CI 2-42%) in the diagnostic yield of SI. However, after adjustment for confounding, the meta-regression analysis showed that FOB usage (p=0.21) and saline concentration (p=0.31) were not independently associated with the diagnostic yield. SI will detect approximately three-quarters of M. tuberculosis culture-positive cases under study conditions. Significant heterogeneity in the diagnostic yield was not explained by HIV prevalence, age, or the use of FOB as the comparator method. The use of a particular nebulized saline concentration for SI cannot be recommended on the basis of this meta-regression analysis.

Safety and tolerability of sputum induction in adolescents and adults with suspected pulmonary tuberculosis

Sputum induction by the inhalation of hypertonic saline may increase the yield of microbiological diagnosis of pulmonary tuberculosis (TB). This is particularly relevant in paucibacillary TB, such as in children or human immunodeficiency virus (HIV)-infected patients. Sputum induction must be shown to be safe and tolerable in community settings where invasive diagnostic methods are unavailable. The objective of this study was to describe the changes in physiological parameters and adverse events occurring during sputum induction in ambulatory adult and adolescent TB suspects recruited in community clinics. Sputum induction was performed in HIV-infected (n = 35) and HIV-uninfected (n = 67) TB suspects (n = 102). Oxygen saturation (%), blood pressure (mm Hg), heart rate (/minute), respiratory rate (/minute), and adverse events were monitored at baseline, continuously during the salbutamol pre-treatment and saline nebulization phases, and for 30 min afterwards. During nebulization, there was a statistically significant increase in oxygen saturation (1%, p < 0.0001), systolic BP (7 mm Hg, p < 0.0001), and diastolic BP (2 mm Hg, p = 0.008). Post-nebulization decrease in the systolic BP occurred (4 mm Hg, p = 0.016). These changes were not considered to be clinically significant. Eight minor, transitory, self-resolving adverse events occurred (labored breathing, n = 2; chest pain, n = 2; paroxysmal coughing, n = 1; elevated heart rate, n = 1; vomiting, n = 1; hypotension, n = 1), leading to procedure termination in four participants. No serious adverse events occurred. Induced sputum is safe, tolerable, and feasible in adult and adolescent TB suspects in a community healthcare setting.

Tuberculosis in special populations

The susceptibility to infection, the pathogenesis and the clinical manifestations of tuberculosis (TB) depend on the immunological status of the host. Immunological status is largely determined by age and comorbidities, but is also affected by other less well known factors. In Spain, most incidental cases of TB arise from the reactivation of remotely acquired latent infections and are favored by the aging of the population and the use of aggressive immunosuppressive therapies. The diagnosis and management of TB in these circumstances is often challenging. On the one hand, the atypical presentation with extrapulmonary involvement may delay diagnosis, and on the other, the toxicity and interactions of the antituberculous drugs frequently make treatment difficult. Immigration from resource-poor, high incidence TB countries, where the social and economic conditions are often suboptimal, adds a new challenge to the control of the disease in Spain. This chapter summarizes our current knowledge of epidemiological, clinical and treatment aspects of TB in particularly susceptible populations.