Tuberculosis in children

Detection of Mycobacterium tuberculosis on stool specimens by PCR among patients with pulmonary tuberculosis

Background:

To detect Mycobacterium tuberculosis on stool specimens by polymerase chain reaction (PCR) among patients with pulmonary tuberculosis. Detection of M. tuberculosis complex in sputum forms the basis of diagnosis of pulmonary tuberculosis. However, some patients tend to swallow sputum and some are unable to produce sputum. Based on the survival of M. tuberculosis in the gastric fluid, swallowed organisms may be detectable in stool samples.

Methods:

The study was carried out on 30 cases each in four groups: sputum smear-positive and sputum smear-negative adults, pediatric patients suspected of pulmonary tuberculosis along with healthy controls. The samples were processed for direct microscopy for acid-fast bacilli (AFB) and M. tuberculosis culture. Stool PCR was done on all 120 samples.

Results:

AFB was demonstrated in 42 and cultured in 39 out of 240 samples. PCR-targeting IS6110 gene showed positive results in 24 (20%) out of 120 stool samples. PCR in stool showed the highest positivity in sputum smear-positive samples followed by gastric aspirates and sputum smear-negative samples.

Conclusion:

Stool PCR is a potentially useful diagnostic method for pulmonary tuberculosis.

Integrated TB and HIV care for Mozambican children: temporal trends, site-level determinants of performance, and recommendations for improved TB preventive treatment

BACKGROUND

Pediatric tuberculosis (TB), human immunodeficiency virus (HIV), and TB-HIV co-infection are health problems with evidence-based diagnostic and treatment algorithms that can reduce morbidity and mortality. Implementation and operational barriers affect adherence to guidelines in many resource-constrained settings, negatively affecting patient outcomes. This study aimed to assess performance in the pediatric HIV and TB care cascades in Mozambique.

METHODS

A retrospective analysis of routine PEPFAR site-level HIV and TB data from 2012 to 2016 was performed. Patients 0-14 years of age were included. Descriptive statistics were used to report trends in TB and HIV indicators. Linear regression was done to assess associations of site-level variables with performance in the pediatric TB and HIV care cascades using 2016 data.

RESULTS

Routine HIV testing and cotrimoxazole initiation for co-infected children in the TB program were nearly optimal at 99% and 96% in 2016, respectively. Antiretroviral therapy (ART) initiation was lower at 87%, but steadily improved from 2012 to 2016. From the HIV program, TB screening at the last consultation rose steadily over the study period, reaching 82% in 2016. The percentage of newly enrolled children who received either TB treatment or isoniazid preventive treatment (IPT) also steadily improved in all provinces, but in 2016 was only at 42% nationally. Larger volume sites were significantly more likely to complete the pediatric HIV and TB care cascades in 2016 (p value range 0.05 to < 0.001).

CONCLUSIONS

Mozambique has made significant strides in improving the pediatric care cascades for children with TB and HIV, but there were missed opportunities for TB diagnosis and prevention, with IPT utilization being particularly problematic. Strengthened TB/HIV programming that continues to focus on pediatric ART scale-up while improving delivery of TB preventive therapy, either with IPT or newer rifapentine-based regimens for age-eligible children, is needed.

Formulation and Bioequivalence Testing of Fixed-Dose Combination Orally Disintegrating Tablets for the Treatment of Tuberculosis in the Paediatric Population

Tuberculosis (TB) is believed to affect around 10 million people worldwide. Treatment for TB includes isoniazid and rifampicin, with fixed-dose combination (FDC) recommended for improved patient compliance. Similarly, orally disintegrating tablets (ODTs) are an increasingly popular dosage form that aid compliance since they do not require swallowing. In this study ODTs of isoniazid and rifampicin, either as discrete or FDC doses, were formulated and bioequivalence between single and combination doses compared using in vitro and in silico approaches. Dissolution profiles were compared using FDA advised difference (f₁) and similarity (f₂) testing in biorelevant media. Rifampicin release from FDCs decreased by approximately 15% in fed-state media (failed f₁ and f₂), which was attributed to enhanced rifampicin degradation in the presence of isoniazid at lower pH. Apparent permeability (P_app) values derived from Caco-2 transport studies were included alongside dissolution results into a physiologically based pharmacokinetic (PBPK) model, to simulate in vivo bioavailability in healthy subjects. Models showed no difference in bioavailability between formulations or dosing (fasted or fed) state, despite the failures in dissolution-based bioequivalence testing, highlighting shortcomings in f₁ and f₂ assessment and the strength of PBPK models.

From Diagnosis to Treatment of Pediatric Tuberculosis: Ten Years Experience in a Single Institution

Aim and Objectives. To describe the patient characteristics, clinical-epidemiologic-microbiologic profile, and treatment outcomes, and to draw attention to tuberculosis (TB) in Turkey. Methods. A retrospective, descriptive study was undertaken of 93 children aged 0 to 18 years who were admitted to Hacettepe University Pediatric Pulmonology Department for treatment from January 2005 to December 2015. Review of hospital records was performed for all children diagnosed as having TB. Results. Pulmonary TB was detected in 51.6% of the patients, extrapulmonary involvement in 33.3%, and pulmonary TB with extrapulmonary involvement in 15.1%. The history of contact with an adult with TB was found in 29% of cases. The most common extrapulmonary TB was TB lymphadenitis. The most common symptom was cough followed by fever and night sweats. One fifth of the patients had normal physical examinations at the time of diagnosis. One fifth (20.4%) of the patients had culture, 17.2% had polymerase chain reaction, and 15% had acid-resistant bacillus positivity. In 21.4% of patients with culture growth, at least one anti-TB drug resistance was found. The mean duration of treatment of patients treated according to the national guideline was 8.6 months (range = 6-36 months). Recovery was seen in 91.4% of patients. Conclusion. The most important way to prevent childhood TB is to fight adult TB through early diagnosis and effective treatment. The presence of contact history must direct us to search for TB. While evaluating children with persisted nonspecific symptoms, TB must be kept in mind even if physical examinations are normal.

Tuberculosis in HIV-infected infants, children, and adolescents in Latin America

OBJECTIVE

To evaluate the occurrence, clinical presentations and diagnostic methods for tuberculosis in a cohort of HIV-infected infants, children and adolescents from Latin America.

METHODS

A retrospective analysis of children with tuberculosis and HIV was performed within a prospective observational cohort study conducted at multiple clinical sites in Latin America.

RESULTS

Of 1114 HIV-infected infants, children, and adolescents followed from 2002 to 2011, 69 that could be classified as having confirmed or presumed tuberculosis were included in this case series; 52.2% (95% CI: 39.8-64.4%) had laboratory-confirmed tuberculosis, 15.9% (95% CI: 8.2-26.7%) had clinically confirmed disease and 31.9% (95% CI: 21.2-44.2%) had presumed tuberculosis. Sixty-six were perinatally HIV-infected. Thirty-two (61.5%) children had a history of contact with an adult tuberculosis case; however information on exposure to active tuberculosis was missing for 17 participants. At the time of tuberculosis diagnosis, 39 were receiving antiretroviral therapy. Sixteen of these cases may have represented immune reconstitution inflammatory syndrome.

CONCLUSIONS

Our study emphasizes the need for adequate contact tracing of adult tuberculosis cases and screening for HIV or tuberculosis in Latin American children diagnosed with either condition. Preventive strategies in tuberculosis-exposed, HIV-infected children should be optimized.

Commentary: a targets framework: dismantling the invisibility trap for children with drug-resistant tuberculosis

Tuberculosis (TB) is an airborne infectious disease that is both preventable and curable, yet it kills more than a million people every year. Children are highly vulnerable, but often invisible casualties. Drug-resistant forms of TB are on the rise globally, and children are as vulnerable as adults but less likely to be counted as cases of drug-resistant disease if they become sick. Four factors make children with drug-resistant TB 'invisible': first, the nature of the disease in children; second, deficiencies in existing diagnostic tools; third, overreliance on these tools; and fourth, our collective failure to deploy one effective tool for finding and treating children - contact investigation. We describe a nascent science-advocacy network - the Sentinel Project on Pediatric Drug-Resistant Tuberculosis - whose goal is to end child deaths from this disease. Provisional annual targets, focused on children exposed at home to multidrug-resistant TB, to be updated every year, constitute a framework to focus attention and collective actions at the community, national, and global levels. The targets in two age groups, under 5 and 5-14 years old, tell us the number of: (i) children who require complete evaluation for TB disease and infection; (ii) children who require treatment for TB disease; and (iii) children who would benefit from preventive therapy.

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.

Risk factors for mortality in Malawian children with human immunodeficiency virus and tuberculosis co-infection

SETTING

A large urban pediatric human immunodeficiency virus (HIV) clinic in Lilongwe, Malawi.

OBJECTIVE

To identify demographic and clinical risk factors for mortality in children co-infected with HIV and tuberculosis (TB).

DESIGN

A retrospective cohort study of HIV-infected children (aged <18 years) enrolled between October 2004 and October 2010 with at least one current or historical TB diagnosis. Descriptive statistics and logistic regression analyses were performed to determine factors associated with mortality.

RESULTS

A total of 1561 patients met the inclusion criteria, representing 32% of patients ever enrolled. Median age at TB diagnosis was 3.8 years (interquartile range 1.5-7.4); 60.9% had severe immune suppression and 47.6% of those with available data had some degree of acute malnutrition at TB diagnosis. Of the 1113 patients with known outcomes, 225 (20.2%) died. Children with TB-HIV co-infection not initiated on antiretroviral therapy (ART) at any time were 8.8 times more likely to die compared to those initiated on ART 0-2 months after initiation of anti-tuberculosis treatment (adjusted OR 8.83, 95%CI 4.42-17.63). Severe immunosuppression and World Health Organization Stage IV were also associated with mortality.

CONCLUSIONS

Pediatric TB-HIV co-infection is common and mortality is high in this cohort of Malawian children. Prompt initiation of ART should be emphasized in this high-risk patient population.

The hidden harm of home-based care: pulmonary tuberculosis symptoms among children providing home medical care to HIV/AIDS-affected adults in South Africa

Millions of children in sub-Saharan Africa undertake personal and medical care for family members who are unwell with AIDS. To date, no research has investigated whether such care provision places children at heightened risk for pulmonary tuberculosis. This study aimed to address this gap by identifying risk factors for paediatric pulmonary tuberculosis symptomatology. In 2009-2011, 6002 children aged 10-17 years were surveyed using door-to-door household sampling of census enumeration areas. These were randomly sampled from six urban and rural sites with over 30% HIV prevalence, within South Africa's three highest tuberculosis-burden provinces. Validated scales and clinical tuberculosis symptom checklists were modelled in multivariate logistic regressions, controlling for socio-demographic co-factors. Findings showed that, among children, severe pulmonary tuberculosis symptomatology was predicted by primary caregiver HIV/AIDS-illness [odds ratio (OR): 1.63, confidence interval (CI): 1.23-2.15, p<0.001], and AIDS-orphanhood (OR: 1.44, CI: 1.04-2.00, p<0.029). Three-fold increases in severe tuberculosis symptoms were predicted by the child's exposure to body fluids through providing personal or medical care to an ill adult (OR: 3.12, CI: 1.96-4.95, p<0.001). Symptoms were also predicted by socio-economic factors of food insecurity (OR: 1.52, CI: 1.15-2.02, p<0.003) and household overcrowding (OR: 1.35, CI: 1.06-1.72, p<0.017). Percentage probability of severe tuberculosis symptoms rose from 1.4% amongst least-exposed children, to 18.1% amongst those exposed to all above-stated risk factors, independent of biological relationship of primary caregiver-child and other socio-demographics. Amongst symptomatic children, 75% had never been tested for tuberculosis. These findings identify the risk of tuberculosis among children providing home medical care to their unwell caregivers, and suggest that there are gaps in the health system to screen and detect these cases of paediatric tuberculosis. There is a need for effective interventions to reduce childhood risk, as well as further support for community-based contact-tracing, tuberculosis screening and anti-tuberculosis treatment for children caring for ill adults in contexts with a high burden of HIV and tuberculosis.

TNF-α/IL-2 ratio discriminates latent from active tuberculosis in immunocompetent children: a pilot study

BACKGROUND

Distinguishing latent tuberculosis (LTB) from tuberculosis (TB) disease may be challenging in children. Here, we analyzed cytokine profiles that can distinguish the two infection stages in a nonendemic country (France).

METHODS

Immunocompetent children with LTB (n = 6) or TB disease (n = 8) (median age: 6.2 and 5.7 years, respectively) were analyzed. Four young uninfected children were included as controls. A Luminex assay evaluated cytokine responses to Mycobacterium tuberculosis antigens.

RESULTS

Poor interleukin-4 (IL-4) and IL-10 responses precluded analysis of these cytokines. Interferon-γ (IFN-γ), tumor necrosis factor-α (TNF-α), IL-2, and T-helper type 1 (Th1) cytokines and IL-5, IL-13, T-helper type 2 (Th2) cytokines were simultaneously induced by antigens in 14/14 infected but 0/4 uninfected children. Th1 cytokine levels were similar in LTB and TB disease: IFN-γ: 12,254 and 10,495 pg/ml; IL-2: 2,097 and 1,869 pg/ml; and TNF-α: 1,020 and 2,875 pg/ml, respectively. Th2 cytokine levels were similar and even higher in LTB than in TB disease: IL-5: 23 and 10 pg/ml; IL-13: 284 and 109 pg/ml, respectively. Positive correlation of cytokine levels, whether Th1 or Th2, was observed. Higher (P = 0.008) TNF-α/IL-2 ratios distinguished 6/8 active TB disease cases from 6/6 LTB cases.

CONCLUSION

TNF-α/IL-2 ratio may discriminate TB disease from LTB in immunocompetent children. Larger studies in TB endemic settings must verify these results.

Tuberculosis and profound hypovitaminosis D in an infant

A young infant presented with a febrile respiratory illness, irritability, and failure to thrive. Clinical evaluation identified that he had profound hypovitaminosis D with severe hypocalcemia and active pulmonary tuberculosis. We review the literature and discuss the current state of knowledge of the interrelationship between Mycobacterium infection and vitamin D status, and its implication to pediatricians.

Unusual spinal tuberculosis with cord compression in an infant

Spinal abscess is rare in children, especially in young infants. The most common etiology is bacteria, Staphylococcus aureus in particular. Mycobacterium tuberculosis is another cause. We report an unusual cervical spinal abscess with spinal cord compression in a 13-month-old child. The presenting symptoms were weakness in the right arm and, predominantly, the right leg for 1 month. Magnetic resonance imaging showed an abscess of the cervical spine, extension with bony destruction, and spinal cord compression. The patient underwent an emergency neurosurgical decompression and laminectomy. Pathology and culture results confirmed Mycobacterium tuberculosis. After 12 months of antituberculosis treatment, the child could walk with a walker. At 37 months, he was able to walk without assistance. We conclude that spinal tuberculosis should be considered in cases of children with spinal cord-compression symptoms and an image showing an extraspinal abscess. Early diagnosis and prompt treatment are critical for maximizing a functional recovery.

Epidemiology of tuberculosis among US- and foreign-born children and adolescents in the United States, 1994-2007

OBJECTIVES

We examined trends in tuberculosis (TB) cases and case rates among US- and foreign-born children and adolescents and analyzed the potential effect of changes to overseas screening of applicants for immigration to the United States.

METHODS

We analyzed TB case data from the National Tuberculosis Surveillance System for 1994 to 2007.

RESULTS

Foreign-born children and adolescents accounted for 31% of 18,659 reported TB cases in persons younger than age 18 years from 1994 to 2007. TB rates declined 44% among foreign-born children and adolescents (20.3 per 10,000 to 11.4 per 100,000 population) and 48% (2.1 per 100,000 to 1.1 per 100,000) among those who were born in the United States. Rates were nearly 20 times as high among foreign-born as among US-born adolescents. Among foreign-born children and adolescents with known month of US entry (88%), more than 20% were diagnosed with TB within 3 months of entry.

CONCLUSIONS

Marked disparities in TB morbidity persist between foreign- and US-born children and adolescents. These disparities and the high proportion of TB cases diagnosed shortly after US entry suggest a need for enhanced pre- and postimmigration screening.

[Diagnosis of tuberculosis in pediatrics. Consensus document of the Spanish Society of Pediatric Infectology (SEIP) and the Spanish Society of Pediatric Pneumology (SENP)]

Tuberculosis is one of the most important health problems worldwide. There are an increased number of cases, including children, due to different reasons in developed countries. The most likely determining cause is immigration coming from high endemic areas. Measures to optimize early and appropriate diagnosis of the different forms of tuberculosis in children are a real priority. Two Societies of the Spanish Pediatric Association (Spanish Society of Pediatric Infectology and Spanish Society of Pediatric Pneumology) have agreed this Consensus Document in order to homogenize diagnostic criteria in pediatric patients.

Mycocerosic acid biomarkers for the diagnosis of tuberculosis in the Coimbra Skeletal Collection

Tuberculosis has been a scourge of humans over many millennia, but questions remain regarding its evolution and epidemiology. Fossil biomarkers, such as DNA and long-chain mycolic acids, can be detected in ancient skeletal and other materials. The phthiocerol dimycocerosate waxes are also robust biomarkers for tuberculosis and sensitive methods are available for the detection of their mycocerosic acid components. The presence of mycocerosic acids was investigated in 49 individuals from the 1837-1936 Coimbra Identified Skeletal Collection (Portugal), half with documentary data indicating tuberculosis as a cause of death. Samples were hydrolysed, acidic components converted to pentafluorobenzyl esters, the non-hydroxylated long-chain esters isolated, and this fraction separated into multimethyl-branched and other esters by normal phase high performance liquid chromatography. Negative ion chemical ionisation gas chromatography mass spectrometry was used to detect diagnostic C29, C30 and C32 mycocerosic acids. Mycocerosic acids were detected in archaeological material for the first time, illustrating that they are valuable biomarkers for the diagnosis of ancient tuberculosis. A 72% correlation with the Coimbra burial record supported TB as the major cause of death. In addition, 30% of the skeletons, positive for mycocerosates, showed the presence of related long-chain mycolipenic acids.

Proposed management of childhood tuberculosis in low-incidence countries

The incidence of childhood tuberculosis continues to decline in central Europe, but due to migration from high incidence countries paediatricians will still be confronted with it. The management of childhood tuberculosis in low-incidence, high-income countries differs from most high-incidence countries. The primary measures for preventing the transmission of tuberculosis to children are the detection of adult source cases, detection of latent TB infection (LTBI) in children by history, tuberculin skin testing and, if necessary and recommended, interferon-gamma release assays. Children with LTBI should receive preventive therapy. The inclusion of tuberculosis in the differential diagnosis of unclear pulmonary and extrapulmonary disease remains important, and tuberculosis has to be managed according to international standards.

Pediatric tuberculosis in Alberta: epidemiology and case characteristics (1990-2004)

BACKGROUND

Pediatric tuberculosis (TB) is important medically and indicative of a public health problem. An understanding of the epidemiology and case characteristics of pediatric TB, in a province that accepts large numbers of immigrants, can inform TB elimination strategy.

METHODS

All cases of pediatric TB notified in Alberta between 1990 and 2004 were identified in the TB Registry. Individual diagnostic criteria were reviewed and case patients were related to a population grid derived from Statistics Canada censuses and population estimates of Status Indians from the Department of Indian and Northern Affairs, Canada. Incidence rates were determined by ethnic group and gender. Clinical/mycobacteriologic case characteristics were compared by ethnic group and birth country.

RESULTS

Among 124 notified cases, 95 (96 episodes) met strict diagnostic criteria: 45 Status Indians, 30 Canadian-born 'other' and 21 foreign-born. Incidence rates were much higher in Status Indians and the foreign-born compared to the Canadian-born 'other'; 10.7, 5.4, and 0.4 per 100,000 person-years, respectively. Among Canadian-born 'other' cases, 12 were Métis and 11 were Canadian-born children of foreign-born parents. Compared to foreign-born cases, Canadian-born cases were more likely to have a source case in Alberta, to be detected through contact tracing, to have primary pulmonary TB, and to have a rural address.

CONCLUSION

Pediatric TB in Alberta is mainly the result of ongoing transmission in Aboriginal peoples and immigration to Canada of persons with latent TB infection. The elimination of pediatric TB will require interruption of transmission in Aboriginal peoples and prevention of disease in immigrants.

Immune function in young children with previous pulmonary or miliary/meningeal tuberculosis and impact of BCG vaccination

OBJECTIVE

Children <5 years old are at increased risk of miliary/meningeal tuberculosis, but the immunologic factors that place them at risk are unknown. BCG vaccine protects against miliary/meningeal tuberculosis, but the mechanism of protection is unknown. We assessed for abnormalities in immune response associated with miliary/meningeal or pulmonary tuberculosis in young children.

PATIENTS AND METHODS

We conducted a case-control study among HIV-seronegative Brazilian children who were <5 years old. Case subjects had previous culture-confirmed or clinical miliary/meningeal tuberculosis. There were 2 sets of control subjects: those with culture-confirmed pulmonary tuberculosis and purified protein derivative-positive household contacts. All of the children had completed treatment. Peripheral blood mononuclear cells were stimulated (phytohemagglutinin, phytohemagglutinin + interleukin 12, lipopolysaccharide, lipopolysaccharide + interferon-gamma, and purified protein derivative), and cytokine responses (interleukin 1beta, interleukin-4, interleukin-6, interleukin-8, interleukin 10, interleukin 12, interferon-gamma, tumor necrosis factor-alpha, and monocyte chemoattractant protein 1) were quantified by bead-based assay. Median cytokine responses were compared by the Kruskal-Wallis test. Multivariate analysis of variance accounted for multiple comparisons.

RESULTS

There were 18 case subjects with miliary/meningeal tuberculosis, 28 pulmonary control subjects, and 29 purified protein derivative-positive control subjects. The median age was 4.2 years. There was no difference in case and control subjects by age, gender, race, BMI, or median CD4 count. Twelve (67%) of 18 case subjects, 26 (93%) of 28 pulmonary control subjects, and 28 (97%) of 29 purified protein derivative-positive subjects had received BCG vaccine. No cytokine defects were identified in case subjects with miliary/meningeal tuberculosis compared with either set of control subjects. Pulmonary control subjects had uniformly higher monocyte chemoattractant protein 1 levels than case subjects with miliary/meningeal tuberculosis and purified protein derivative-positive control subjects, both at rest and with lipopolysaccharide, lipopolysaccharide + interferon-gamma, and purified protein derivative stimulation. Pulmonary control subjects did not have a higher frequency of allele G in the -2518 monocyte chemoattractant protein 1 promoter polymorphism. Case subjects with miliary/meningeal tuberculosis who had received BCG vaccine (n = 12) had lower stimulated interleukin 8 production than children who did not receive BCG vaccine (n = 6).

CONCLUSIONS

Children with previous miliary/meningeal tuberculosis did not have a major defect in the cytokine pathways studied. Increased monocyte chemoattractant protein 1 levels were associated with pulmonary disease, occurred despite BCG vaccination, and were not associated with a polymorphism in the monocyte chemoattractant protein 1 promoter.

T-SPOT.TB: an in vitro diagnostic assay measuring T-cell reaction to Mycobacterium tuberculosis-specific antigens

The overall sensitivity of the RD1 ELISPOT assay (T-SPO.TB), which counts T cells sensitized to specific Mycobacterium tuberculosis peptide sequences, was 81-97% in populations with confirmed tuberculosis, in whom 39-78% had immunosuppressive conditions. In patients with confirmed tuberculosis, the respective RD1 ELISPOT versus tuberculin skin test (TST) sensitivities were 100% versus 89% in adults and 77% versus 35% in children (of whom 39% were HIV-positive). In contrast to that of the TST, the sensitivity of the RD1 ELISPOT assay was not significantly affected by age <36 months, or the immunological or nutritional status of the subjects. Specificity was 100% in two UK-based studies. Isolated false positives have been recorded in patients infected with non-tuberculous M. kansasii. A study investigating latent tuberculosis infection found no significant difference in results between HIV-positive and -negative participants for the RD1 ELISPOT assay, while the TST varied significantly with HIV status. Contact-tracing studies have demonstrated concordance between the RD1 ELISPOT assay and the TST of 65-89%. There is a significant correlation between a positive result and the degree of exposure to the index case for the RD1 ELISPOT assay, but not for the TST, in contact-tracing studies. Unlike the TST, the RD1 ELISPOT assay is not confounded by bacille Calmette-Guérin vaccination.

Clinical investigation of cavitary tuberculosis and tuberculous pneumonia

BACKGROUND

[corrected] The radiographic characteristics of tuberculous pneumonia in adults are similar to primary tuberculosis that occurs in childhood, and upper lobe cavitary tuberculosis is the hallmark of postprimary tuberculosis. The purpose of this study was to investigate the factors associated with tuberculous pneumonia by making comparison with cavitary tuberculosis.

METHODS

The medical records and radiographic findings of patients with cavitary tuberculosis and tuberculous pneumonia, and who were diagnosed between March 2003 and February 2006, were analyzed retrospectively.

RESULTS

Forty patients had cavitary tuberculosis and sixteen patients had tuberculous pneumonia. Fever was more frequent for tuberculous pneumonia, whereas hemoptysis was more frequent for cavitary tuberculosis. The duration of symptoms before visiting the hospital was shorter, but the diagnosis after admission was more delayed for tuberculous pneumonia patients than for cavitary tuberculosis patients. The prevalence of underlying comorbidities such cancer, diabetes, alcoholism and long-term steroid use was not different between the two groups. The patients with tuberculous pneumonia were older and they had lower levels of serum albumin and hemoglobin than those with cavitary tuberculosis. The patients with tuberculous pneumonia showed a tendency to have more frequent endobronchial lesion. Tuberculous pneumonia occurred in any lobe, whereas the majority of cavitary tuberculosis patients had upper lung lesion, but the prevalence of lymphadenopathy, pleural effusion and previous tuberculosis scar was not different between the two groups.

CONCLUSIONS

Older age, a lower level of serum albumin and hemoglobin and a random distribution of lesion were associated with tuberculosis pneumonia as compared with cavitary tuberculosis. These findings suggest that the pathogenesis of tuberculous pneumonia might be different from that of cavitary tuberculosis.

Tuberculous otitis media developing as a complication of tympanostomy tube insertion

Primary tuberculous otitis media of which infection focus cannot be found elsewhere in the body is a rare disease. Route of the infection has been hypothesized as Eustachian tube or external auditory canal with tympanic membrane perforation but it is hard to ascertain in the patient. We present a case of an 8-year-old child who suffered chronic otorrhea after tympanostomy tube insertion. The radiological and histopathological findings revealed tuberculous otitis media, which occurred as a complication of tympanostomy tube insertion.

Balancing prevention and screening among international migrants with tuberculosis: Population mobility as the major epidemiological influence in low-incidence nations

BACKGROUND

Tuberculosis infection and disease remain a significant cause of global morbidity and mortality. The burden of tuberculosis disease is greatest in the developing nations of the world, although the effect of imported disease is observed in low-incidence tuberculosis regions, represented predominantly by high-income countries. In these regions, national tuberculosis control and elimination programmes are increasingly challenged to address disease in foreign-born residents. Immigration policies and shifting migration patterns over the past 5 decades have brought larger numbers of permanent and temporary residency migrants from high-prevalence regions of the world into low tuberculosis incidence environments. As a consequence, both national immigration policies and global health strategies for the control of tuberculosis share common interest in mobile populations moving from high-to-low prevalence regions. Existing immigration medical screening practices in major immigrant-receiving nations were often designed to prevent and manage the importation of contagious, active pulmonary tuberculosis disease. Such programmes may be limited in addressing the long-term consequences of latent tuberculosis infection in foreign-born residents. In nations with a low incidence of tuberculosis, a direct link can be found between the globalization of health factors related to international population movements, as observed with tuberculosis and immigration policies and practices. Continued migration from high-endemic tuberculosis regions will increasingly influence the disease burden in low-endemic areas, and challenge local tuberculosis control and elimination programmes. Evidence-based approaches to meeting those challenges will allow for the effective use of resources and support ongoing programme evaluation.

Improved recovery of Mycobacterium tuberculosis from children using the microscopic observation drug susceptibility method

OBJECTIVE

The diagnosis of pulmonary tuberculosis presents challenges in children, because symptoms are nonspecific, sputa are not accessible, and Mycobacterium tuberculosis cultures and smears often are negative. The Microscopic Observation Drug Susceptibility technique is a simple, inexpensive method for Mycobacterium tuberculosis isolation with superior speed and sensitivity over Lowenstein-Jensen culture in studies of adults with pulmonary tuberculosis. The objective of this study was to determine whether Microscopic Observation Drug Susceptibility culture can improve the sensitivity and the speed of Mycobacterium tuberculosis recovery among Peruvian children with symptoms suggestive of pulmonary tuberculosis.

METHODS

Two specimens of each type (gastric aspirate, nasopharyngeal aspirate, and stool specimens) were collected from each patient, examined by auramine stain, and cultured by Microscopic Observation Drug Susceptibility and Lowenstein-Jensen techniques. Patients (n = 165) were enrolled between April 2002 and February 2004 at the Instituto de Salud del Niño, the major pediatric hospital in Lima, Peru. Inclusion criteria were age < or = 12 years, Stegen-Toledo clinical score > or = 5 points, and absence of antituberculous therapy. The main outcome measurements were (1) proportion of specimens that were culture positive by Microscopic Observation Drug Susceptibility versus Lowenstein-Jensen and (2) days required for positive culture result, stratified by specimen type and auramine stain result.

RESULTS

Fifteen (9%) patients had at least 1 positive Mycobacterium tuberculosis culture (from stool in 3 cases, nasopharyngeal aspirate in 8 cases, and gastric aspirate in 15 cases). Thirty-eight culture-positive specimens were obtained (22 gastric aspirate, 12 nasopharyngeal aspirates, and 4 stools). Microscopic Observation Drug Susceptibility provided significantly more positive cultures than Lowenstein-Jensen (33 of 38 specimens culture positive by Microscopic Observation Drug Susceptibility vs 21 of 38 by Lowenstein-Jensen). This was attributed to enhanced recovery of Mycobacterium tuberculosis from auramine-negative specimens (19 of 23 by Microscopic Observation Drug Susceptibility vs 9 of 23 by Lowenstein-Jensen), in contrast to similar detection rates for the 2 tests with auramine-positive samples. Similar results were found for analyses that were limited to gastric aspirates. Isolation was faster by Microscopic Observation Drug Susceptibility than Lowenstein-Jensen.

CONCLUSIONS

Isolation of Mycobacterium tuberculosis from children with suspected pulmonary tuberculosis by Microscopic Observation Drug Susceptibility demonstrated greater yield and faster recovery than by Lowenstein-Jensen method, significantly improving local capabilities to detect pediatric tuberculosis in resource-poor settings.

Early detection of perinatal tuberculosis using a whole blood interferon-gamma release assay

BACKGROUND

The diagnosis of perinatal tuberculosis (TB) is problematic because of its nonspecific presentation, the difficulty of obtaining microbiological confirmation, and the unreliability of the tuberculin skin test. Immunodiagnosis of TB has received new attention with the discovery of Mycobacterium tuberculosis-specific immunodominant antigens (early secreted antigenic target 6 [ESAT-6] and culture filtrate protein 10 [CFP-10]) that are encoded by the RD1 region of the pathogen. A whole blood assay has recently been developed to quantitatively measure interferon- gamma production by lymphocytes specific to these antigens, but its evaluation in the diagnosis of TB in infants and children has been limited to date.

METHODS

In addition to routine diagnostic evaluation (tuberculin skin tests, culture of early-morning gastric aspirate samples, and chest radiographs), 2 infants with suspected perinatal TB were investigated with a whole blood interferon-gamma release assay.

RESULTS

The results of the tuberculin skin tests were negative for both patients. The findings of the chest radiographs were abnormal with features suggestive of miliary TB. A whole blood interferon- gamma release assay was performed and yielded positive results within 48 h after admission to the hospital for both patients, prompting early antituberculous treatment. M. tuberculosis was cultured after 6 weeks from gastric aspirate samples collected on admission to the hospital from both infants. At 6 months of age, both infants were thriving and had acheived normal developmental milestones.

CONCLUSIONS

The advent of interferon- gamma release assays may prove to be useful in the evaluation of infants with suspected perinatal TB.

Tuberculosis in children: an update

TB is a common and serious global infection that is spread exclusively from person to person. The initial infection in most healthy people leads to LTBI 95% of the time, but untreated individuals have a 5% to 10% lifetime risk for reactivating their infection to develop highly infectious cavitary pulmonary TB or extrapulmonary disease. Following primary infection progressive disease is more likely to develop in children younger than 5 years old or those who are immunocompromised, particularly those with HIV infection. The diagnosis of TB in most of the world depends on the presence of a clinical illness typical for TB in concert with radiographic changes, the presence of AFB in sputum, or a positive TST. Newer methods of in vitro stimulation of T lymphocytes from TB-infected people to produce interferon may be more accurate than a TST but have yet to be well studied in children. Treatment of children with LTBI is generally 9 months of daily isoniazid unless the child has been in contact with an adult with known isoniazid-resistant TB. For active TB, children generally are treated for 6 months with an initial 2 months of isoniazid, rifampin, and pyrazinamide. Where exposure to an isoniazid-resistant strain is likely, ethambutol is added. After 2 months, pyrazinamide is discontinued unless the patient has been confirmed to have been infected with a resistant strain of M. tuberculosis. BCG, rarely used in the United States, is still considered important to prevent meningitis and miliary disease in very young children in areas of the world with a high prevalence of TB.