Prevalence of Latent Tuberculosis Infection Among Healthy Young Children and Adolescents and a Two-step Approach for the Diagnosis of Tuberculosis Infection in Chengdu, China

BACKGROUND

China has a high burden of tuberculosis and latent tuberculosis infection (LTBI). The aim of this study was to estimate the prevalence of LTBI among healthy young children and adolescents and test a 2-step approach to explore the threshold for the diagnosis of tuberculosis infection in Chengdu, China.

METHODS

Healthy preschool children and school-going children in Chengdu, Sichuan Province, were screened for LTBI using the tuberculin skin test (TST). Preschool children with TST ≥ 5 mm also underwent interferon-γ release assay (IGRA) to explore the threshold of this 2-step approach.

RESULTS

In total, 5667 healthy young children and adolescents completed TST test between July 2020 and January 2021 and were included in the present analysis. The age of the participants ranged from 2.4 to 18 years (median 7.25 ± 4.514 years), of which 2093 (36.9%) were younger than 5 years. The overall prevalence of LTBI was 6.37% and 6.64% in children younger than 5 years old. Fourteen of the 341 preschool children with TST ≥5 mm were interferon-γ release assay positive, of which 4 showed a TST result of 5-10 mm, and 6 preschool children received preventive treatment for LTBI.

CONCLUSIONS

Healthy young children and adolescents should also be considered as important target populations for LTBI screening. TST can be recommended for first-line screening as part of a 2-step approach for LTBI screening using a positive threshold of 5 mm.

Brief Report: Yield of Repeat Tuberculin Skin Testing for People Living With HIV in Brazil

OBJECTIVES

In Brazil, annual tuberculin skin tests (TSTs) are recommended for people living with HIV (PLWH) with CD4 >350, with tuberculosis preventive therapy provided on test conversion. We aimed to determine the yield of repeat TSTs for PLWH.

DESIGN

Secondary analysis of the stepped-wedge, cluster-randomized THRio trial for isoniazid preventive therapy (IPT) to prevent tuberculosis (TB).

METHODS

We analyzed data from newly registered PLWH with negative baseline TST results. We calculated the number of TST conversions after 1 and/or 2 years among patients eligible for follow-up TSTs, the proportion of converters initiating IPT, and incidence of TB/death.

RESULTS

Among 1770 PLWH with a negative baseline TST, 679 (38%) were female and median age was 36 years (IQR 29-43). Eighty-six (5%) developed TB or died within 1 year. Among 1684 eligible for a follow-up 1-year TST, 582 (35%) were tested and 53 (9%) were positive. Forty-nine converters (92%) started IPT. Of 529 patients with a negative 1-year TST, 7 (1%) developed TB or died over the following year. Of 522 patients eligible for a 2-year TST, 158 (30%) were tested and 13 (8%) were positive. Ten converters (77%) started IPT. Of 1102 patients who did not receive a 1-year TST, 33 (3%) developed TB or died. Of the 1069 patients eligible for a 2-year TST, 259 (24%) were tested and 34 (13%) were positive. Thirty converters (88%) started IPT.

CONCLUSIONS

In this cohort of PLWH in Brazil, TST conversion was high among those retested, but only 48% received a follow-up TST within 2 years.

IgG4-Related Disease With Tuberculosis: A Case Report and Retrospective Review of Patients in a Single Center

Background

IgG4-related disease (IgG4-RD) is a recently recognized systemic fibro-inflammatory disease of unknown cause involving many organs including pancreas, salivary glands, and lymph nodes. Chronic tuberculosis (TB) infection has been reported in IgG4-RD, but the prevalence of TB infection has not been evaluated in IgG4-RD.

Methods

Characterization of a patient with IgG4-RD by physical examination, laboratory tests, magnetic resonance imaging (MRI) and histological examination. TB infection was evaluated by medical history, radiological examinations, sputum examinations, tubercular skin test (TST) and interferon gamma (IFN-γ) release assay test (IGRA). Medical records of IgG4-RD patients were reviewed in our institute from February 2015 to September 2020 to explore the prevalence of TB infection in IgG4-RD.

Results

We described a 40-year-old Chinese man presented with headache and diplopia. Physical examination revealed bitemporal hemianopsia and limited abduction of both eyes. MRI revealed uniformly enhancing mass overlying clivus with dural tail sign. Laboratory data revealed elevation of IgG4 (1.9g/L), and TB-IGRA demonstrated significantly elevated IFN-γ (414.21 pg/ml). The clivus lesion was subtotally removed and IgG4 was strongly positive on immunohistochemical staining. The diagnosis of IgG4-RD was established, and the patient received treatment of corticosteroids, methotrexate, and cyclophosphamide with isoniazid prophylaxis. Consequently, the mass shrank remarkably within 3 months. A similar concurrence of TB disease or latent TB infection (LTBI) and IgG4-RD was present in 17/47 (36.2%) patients in our institute.

Conclusion

High frequency of TB/LTBI presented in patients with IgG4-RD. Patients with IgG4-RD and LTBI should be closely monitored for resurgence of TB. Whether TB represents a risk for IgG4-RD should be further investigated in prospective cohort.

Implementation of latent tuberculosis infection screening and treatment among newly arriving immigrants in the Netherlands: A mixed methods pilot evaluation

INTRODUCTION

To reach pre-elimination levels of tuberculosis (TB) incidence in the Netherlands, prevention of TB among immigrants through diagnosis and treatment of latent TB infection (LTBI) is needed. We studied the feasibility of a LTBI screening and treatment program among newly arriving immigrants for national implementation.

METHODS

We used mixed methods to evaluate the implementation of LTBI screening and treatment in five Public Health Services (PHS) among immigrants from countries with a TB incidence >50/100,000 population. We used Poisson regression models with robust variance estimators to assess factors associated with LTBI diagnosis and LTBI treatment initiation and reported reasons for not initiating or completing LTBI treatment. We interviewed five PHS teams using a semi-structured method to identify enhancing and impeding factors for LTBI screening and treatment.

RESULTS

We screened 566 immigrants; 94 (17%) were diagnosed with LTBI, of whom 49 (52%) initiated and 34 (69%) completed LTBI treatment. LTBI diagnosis was associated with male gender, higher age group, higher TB incidence in the country of origin and lower level of education. Treatment initiation was associated with PHS (ranging from 29% to 86%), lower age group, longer intended duration of stay in the Netherlands, and lower level of education. According to TB physicians, clients and their consulted physicians in the home country lacked awareness about benefits of LTBI treatment. Furthermore, TB physicians questioned the individual and public health benefit of clients who return to their country of origin within the foreseeable future.

CONCLUSIONS

Doubt of physicians in both host country and country of origin about individual and public health benefits of LTBI screening and treatment of immigrants hampered treatment initiation: the high initiation proportion in one PHS shows that if TB physicians are committed, the LTBI treatment uptake can be higher.

Role Of Tuberculin Test As A Diagnostic Tool For Tuberculosis

BACKGROUND

Childhood Tuberculosis remains one of the major public health concerns in developing countries like Pakistan and is responsible for high rates of morbidity and mortality in children. Although tuberculin skin test is very commonly used by physicians all over the world, its interpretation always remains difficult and challenging. The objective of this study was to determine the frequency of positive tuberculin skin test in vaccinated and unvaccinated children suffering from tuberculosis.

METHODS

This Cross-sectional study was conducted in the department of Paediatric Ayub Teaching Hospital, Abbottabad from 1st February 2015 to 30th April 2016. A total of 150 patients were observed in this study. Children of either gender who were aged 1-15 years admitted in ward with tuberculosis were included in the study by using nonprobability convenient sampling technique. We injected 0.1 ml (10 units) of tuberculin purified protein derivative (PPD) into the anterior surface of the forearm and induration was read at 72 hours after administration. Data was entered and analysed using SPSS version 10.

RESULTS

Out of 150 children, 84 (56%) were males and 66 (44%) were females. The mean age was 7.8±3.84 years. Of these 75 (50%) were vaccinated and 75 (50%) were unvaccinated. In vaccinated Group 5.3% children had positive tuberculin skin test while in unvaccinated Group 2.7% children had positive tuberculin skin test and this difference was found statistically insignificant (pvalue= 0.40). Pulmonary TB was the diagnosis in 67 (44.7%), TBM in 65 (43.3%), abdominal TB in 7 (4.7%), disseminated TB in 4 (2.7%) and military TB in 7 (4.7%) patients.

CONCLUSIONS

The positivity of tuberculin skin test in vaccinated and unvaccinated children suffering from tuberculosis was found to be insignificant in our study. We conclude that Tuberculin Skin Test should not be used as a sole diagnostic tool for diagnosing the disease in children of our region..

Care Cascade for targeted tuberculosis testing and linkage to Care in Homeless Populations in the United States: a meta-analysis

BACKGROUND

Homelessness increases the risk of tuberculosis (TB) disease and latent TB infection (LTBI), but persons experiencing homelessness often lack access to testing and treatment. We assessed the yield of TB testing and linkage to care for programs targeting homeless populations in the United States.

METHODS

We conducted a comprehensive search of peer-reviewed and grey literature, adapting Cochrane systematic review methods. Two reviewers independently assessed study eligibility and abstracted key data on the testing to care cascade: number of persons reached, recruited for testing, tested for LTBI, with valid test results, referred to follow-up care, and initiating care. We used random effects to calculate pooled proportions and 95% confidence intervals (CI) of persons retained in each step via inverse-variance weighted meta-analysis, and cumulative proportions as products of adjacent step proportions.

RESULTS

We identified 23 studies published between 1986 and 2014, conducted in 12 states and 15 cities. Among studies using tuberculin skin tests (TST) we found that 93.7% (CI 72.4-100%) of persons reached were recruited, 97.9% (89.3-100%) of those recruited had tests placed, 85.5% (78.6-91.3%) of those with tests placed returned for reading, 99.9% (99.6-100%) of those with tests read had valid results, and 24.7% (21.0-28.5%) with valid results tested positive. All persons testing positive were referred to follow-up care, and 99.8% attended at least one session of follow-up care. Heterogeneity was high for most pooled proportions. For a hypothetical cohort of 1000 persons experiencing homelessness reached by a targeted testing program using TST, an estimated 917 were tested, 194 were positive, and all of these initiated follow-up care.

CONCLUSIONS

Targeted TB testing of persons experiencing homelessness appears effective in detecting LTBI and connecting persons to care and potential treatment. Future evaluations should assess diagnostic use of interferon gamma release assays and completion of treatment, and costs of testing and treatment.

Use of tuberculin skin test for assessment of immune recovery among previously malnourished children in Ethiopia

OBJECTIVE

To compare levels of immunity in children recovering from severe acute malnutrition (cases) against those of community controls (controls).

RESULTS

At baseline children recovering from severe acute malnutrition had lower, mid upper arm circumference (122 mm for cases and 135 mm for controls; p < 0.001), weight-for-height Z-score (- 1.0 for cases and - 0.5 for controls; p < 0.001), weight-for-age Z-score (- 2.8 for cases and - 1.1 for controls; p < 0.001) and height/length-for-age Z-score (- 3.6 for cases and - 1.4 for controls; p < 0.001), than controls. Age and gender matched community controls. At baseline, prevalence of a positive tuberculin skin test, assessed by cutaneous delayed-type hypersensitivity reaction skin test, was very low in both cases (3/93 = 3.2%) and controls (2/94 = 2.1%) and did not significantly increase at 6 months follow up (6/86 = 7.0% in cases and 3/84 = 3.4% in controls). The incidences of common childhood morbidities, namely fever, diarrhoea and cough, were 1.7-1.8 times higher among cases than controls. In conclusion, these results show that tuberculin skin test does not enable any conclusive statements regarding the immune status of patients following treatment for severe acute malnutrition. The increased incidence of infection in cases compared to controls suggests persistence of lower resistance to infection even after anthropometric recovery is achieved.

National position statement for the management of latent tuberculosis infection

The primary role of any tuberculosis (TB) control program is to ensure the prompt identification and effective treatment of active disease. The host immune system often succeeds in containing the initial (or primary) infection with Mycobacterium tuberculosis (Mtb), but may fail to eliminate the pathogen. The persistence of viable organisms explains the potential for the development of active disease years or even decades after infection. This is known as latent tuberculosis infection (LTBI) although, rather than a distinct entity, this probably represents part of a dynamic spectrum. Individuals with LTBI are asymptomatic and it is therefore clinically undetectable. The World Health Organization (WHO) estimates that one-third of the global population has been infected with Mtb, with highest prevalence of LTBI in countries/regions with the highest prevalence of active disease. In 2013, 88% of 1322 notifications in Australia were in the overseas-born population (incidence 19.5 per 100,000 v. 1.0 per 100,000), with this proportion rising over the course of the last decade. Combined with epidemiological evidence of low local transmission, this strongly implies that the vast majority resulted from reactivation of latent infection acquired prior to immigration. Contrasting trends in TB incidence in other developed countries probably reflect differences in policy regarding LTBI.

CONCLUSION

The diagnosis and treatment of LTBI represents an important opportunity for intervention by jurisdictional TB control programs.

Comparing tuberculin skin test and interferon γ release assay (T-SPOT.TB) to diagnose latent tuberculosis infection in household contacts

BACKGROUND/AIMS

The tuberculin skin test (TST) and interferon γ release assay are currently used as diagnostic tools to detect latent tuberculosis (TB) infection; however, there are inconsistencies about the degree of agreement between the tests. We aimed to evaluate the concordance rate between the two tests in household contacts of a country with intermediate TB burden, where most people were vaccinated.

METHODS

We recruited household contacts who spent > 8 hours daily with patients with microbiologically confirmed active pulmonary TB, and received both TST and T-SPOT.TB (Oxford Immunotec) simultaneously. The degree of agreement was analysed according to TST cutoff and Bacille Calmette-Guerin (BCG) vaccination status. Relevant factors were analysed to establish the association with TST or T-SPOT.TB.

RESULTS

Among 298 household contacts, 122 (40.9%) were spouses, and 250 (83.9%) had received BCG vaccination. In the contact sources, 117 (39.3%) showed a positive result for acid-fast bacillus (AFB) sputum smear and 109 (36.6%) had cavities. The highest agreement rate of 69.5% and κ value of 0.378 were found with a 10 mm cutoff. Spouse, time interval from TB diagnosis to test, and AFB sputum smear positivity were significantly associated with a positive result for T-SPOT.TB. Sex, BCG vaccination, and cavity on chest computed tomography were related to TST positivity.

CONCLUSIONS

The present study suggested it was not possible for TST and T-SPOT.TB to replace each other because of considerable discrepancy between the two tests in household contacts in a country with intermediate TB prevalence.

Status of Tuberculosis services in Indian Prisons

INTRODUCTION

Prisons are known to be a high risk environment for tuberculosis (TB) due to overcrowding, low levels of nutrition, poor infection control and lack of accessible healthcare services. India has nearly 1400 prisons housing 0.37 million inmates. However, information on, availability of diagnostic and treatment services for TB in the prison settings is limited. This study examined the availability of TB services in prisons of India. Simultaneously, prison inmates were screened for tuberculosis.

METHOD

The study was conducted in 157 prisons across 300 districts between July-December 2013. Information on services available and practices followed for screening, diagnosis and treatment of TB was collected. Additionally, the inmates and prison staff were sensitised on TB using interpersonal communication materials. The inmates were screened for cough ≥2 weeks as a symptom of TB. Those identified as presumptive TB patients (PTBP) were linked with free diagnostic and treatment services.

RESULTS

Diagnostic and treatment services for TB were available in 18% and 54% of the prisons respectively. Only half of the prisons screened inmates for TB on entry, while nearly 60% practised periodic screening of inmates. District level prisons (OR, 6.0; 95% CI, 1.6-22.1), prisons with more than 500 inmates (OR, 52; 95% CI, 1.4-19.2), and prisons practising periodic screening of inmates (OR, 2.7; 95% CI, 1.0-7.2) were more likely to diagnose TB cases. 19% of the inmates screened had symptoms of TB (cough ≥2 weeks) and 8% of the PTBP were diagnosed with TB on smear microscopy.

CONCLUSION

The TB screening, diagnostic and treatment services are sub-optimal in prisons in India and need to be strengthened urgently.

Quantitative genetic analysis of the bTB diagnostic single intradermal comparative cervical test (SICCT)

BACKGROUND

Bovine tuberculosis (bTB) is a disease of significant economic importance and is a persistent animal health problem with implications for public health worldwide. Control of bTB in the UK has relied on diagnosis through the single intradermal comparative cervical test (SICCT). However, limitations in the sensitivity of this test hinder successful eradication and the control of bTB remains a major challenge. Genetic selection for cattle that are more resistant to bTB infection can assist in bTB control. The aim of this study was to conduct a quantitative genetic analysis of SICCT measurements collected during bTB herd testing. Genetic selection for bTB resistance will be partially informed by SICCT-based diagnosis; therefore it is important to know whether, in addition to increasing bTB resistance, this might also alter genetically the epidemiological characteristics of SICCT.

RESULTS

Our main findings are that: (1) the SICCT test is robust at the genetic level, since its hierarchy and comparative nature provide substantial protection against random genetic changes that arise from genetic drift and from correlated responses among its components due to either natural or artificial selection; (2) the comparative nature of SICCT provides effective control for initial skin thickness and age-dependent differences; and (3) continuous variation in SICCT is only lowly heritable and has a weak correlation with SICCT positivity among healthy animals which was not significantly different from zero (P > 0.05). These emerging results demonstrate that genetic selection for bTB resistance is unlikely to change the probability of correctly identifying non-infected animals, i.e. the test's specificity, while reducing the overall number of cases.

CONCLUSIONS

This study cannot exclude all theoretical risks from selection on resistance to bTB infection but the role of SICCT in disease control is unlikely to be rapidly undermined, with any adverse correlated responses expected to be weak and slow, which allow them to be monitored and managed.

Tuberculosis in Poland in 2014

AIM OF THE STUDY

To evaluate the main features of TB epidemiology in 2014 in Poland and to compare with the data on the same phenomena in EU/EEA countries.

METHODS

Analysis of case- based data on TB patients from National TB Register, data on anti-TB drugsusceptibility testing results in cases notified in 2014, data from National Institute of Public Health- NationalInstitute of Hygiene on cases of tuberculosis as AIDS-defining disease, data from Central Statistical Office ondeaths from tuberculosis based on death certificates, data from ECDC report „ European Centre for DiseasePrevention and Control/WHO Regional Office for Europe. Tuberculosis surveillance and monitoring in Europe 2016. Stockholm: European Centre for Disease Prevention and Control, 2016”.

RESULTS

6 698 TB cases were reported in Poland in 2014. The incidence rate was 17.4 cases per 100 000, withlarge variability between voivodeships from 9.3 to 26.5 per 100 000. The mean annual decrease of TB incidence in 2010- 2014 was 2.1%. 6 066 cases had no history of previous treatment i.e. 15.8 per 100 000. 632 cases i.e. 1.6 per 100 000 – 9.4% of all registered subjects were relapses. The number of all notified pulmonary tuberculosis cases in 2014 was 6311 i.e. 16.4 per 100 000. Pulmonary cases represented 94.2% of all TB cases. In the presented year 387 extrapulmonary TB cases were reported. Children with TB (70 cases) accounted for 1.0% of all cases notified in Poland. The incidence of tuberculosis increases with age from 1.2 per 100 000 among children to 30.4 per 100 000 among patients 65 years old and older. The incidence among men i.e. 24.6 per 100 000 was 2.3 times higher than among women i.e. 10.7 per 100 000. The biggest difference in the TB incidence between the two sex groups occurred in persons aged 45 to 49 years – 40.4 vs. 9.3. The TB incidence in rural population was lower than in urban, respectively 17.0 per 100 000 and 17.7 per 100 000. The number of all registered culture positive TB cases, including relapses, was 4 781. Culture-confirmed cases constituted 71.4% of all TB cases and 72.9% of all pulmonary TB cases. The number of smear-positive pulmonary TB cases reported in 2014 was 2800 i.e. 7.3 per 100 000 respectively what constituted 44.4% of all pulmonary TB cases. TB was initial AIDS indicative disease in 13 persons. In Poland in 2014 there were 35 cases with MDR-TB (including 7 patients of foreign origin) and 97 patients with resistance to isoniazid only, constituting respectively 0.8% and 2.2% of cases with known DST results (DSTs were done in 93.3% of all culture-confirmed TB cases). In 2014, there were 49 foreign-origin TB cases reported in Poland. There were 532 deaths due to tuberculosis reported in 2013 – 1.4 per 100 000; 518 and 14 from extrapulmonary tuberculosis. Mortality among males – 2.2 per 100.000 – was 3.6 X higher than among females – 0.6. 38,5% of all TB deaths were cases 65 years old and older – 3.7 per 100 000. There were no deaths from tuberculosis in children. TB was cause of death in one adolescent. TB mortality in 2013 constituted 0.14% of total mortality in Poland and 27.1% of mortality from infectious diseases.

CONCLUSIONS

In Poland in 2014 the incidence of tuberculosis was higher than the average in EU/EEA countries. The highest incidence rates occurred in older age groups. The incidence in men was more than 2 times higher than in women. In Poland, unfavorable phenomena as tuberculosis in children, tuberculosis in persons infected with HIV and MDR-TB are less common than in EU/EEA countries.

Evaluation of a diagnostic flow chart applying medical thoracoscopy, adenosine deaminase and T-SPOT.TB in diagnosis of tuberculous pleural effusion

OBJECTIVE

To evaluate a diagnostic flow chart applying medical thoracoscoy (MT), adenosine deaminase (ADA) and T-SPOT.TB in diagnosis of tuberculous pleural effusion (TPE) at a high TB burden country.

PATIENTS AND METHODS

136 patients with pleural effusion (PE) were enrolled and divided into TPE and Non-TPE group. MT (histology), PE ADA and T-SPOT.TB were conducted on all patients. ROC analysis was performed for the best cut-off value of PE ADA in detection of TPE. The diagnostic flow chart applying MT, ADA and T-SPOT.TB was evaluated for improving the limitations of each diagnostic method.

RESULTS

ROC analysis showed that the best cut-off value of PE ADA was 30U/L. The sensitivity and specificity of these tests were calculated respectively to be: 71.4% (58.5%-81.6%) and 100% (95.4-100.0%) for MT, 92.9% (83.0-97.2%) and 68.8% (57.9-77.9%) for T-SPOT.TB, and 80.0% (69.6-88.1%) and 92.9% (82.7-98.0%) for PE ADA. The sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, positive predictive value and negative predictive value of the diagnostic flow chart were 96.4% (87.9-99.0%), 96.3% (89.6-98.7%), 25.714, 0.037, 97.4 and 94.9, respectively.

CONCLUSIONS

The diagnostic flow chart applying MT, ADA and T-SPOT.TB is an accurate and rapid diagnostic method in detection of TPE.

Costs of Implementing and Maintaining a Tuberculin Skin Test Program in Hospitals and Health Departments

Objective:

To determine (1) the annual costs of implementing and maintaining tuberculin skin test (TST) programs at participating study sites, (2) the cost of the TST program per healthcare worker (HCW), and (3) the outcomes of the TST programs, including the proportion of HCWs with a documented TST conversion and the proportion who accepted and completed treatment for latent TB infection, before and after the implementation of staffTRAK-TB software (Centers for Disease Control and Prevention, Atlanta, GA).

Design:

Cost analysis in which costs for salaries, training, supplies, radiography, and data analysis were collected for two 12-month periods (before and after the implementation of staffTRAK-TB).

Setting:

Four hospitals (two university and two city) and two health departments (one small county and one big city).

Results:

The annual cost of implementing and maintaining a TST program ranged from $66,564 to $332,728 for hospitals and $92,886 to $291,248 for health departments. The cost of the TST program per HCW ranged from $41 to $362 for hospitals and $176 to $264 for health departments.

Conclusions:

Costs associated with implementing and maintaining a TST program varied widely among the participating study sites, both before and after the implementation of staffTRAK-TB. Compliance with the TB infection control guidelines of the Centers for Disease Control and Prevention may require a substantial investment in personnel time, effort, and commitment.

Utility of Dual Skin Tests to Evaluate Tuberculin Skin Test Reactions of 10 to 14 mm in Healthcare Workers

Objective:

To define the utility of 10- to 14-mm reactions to a Mycobacterium tuberculosis purified protein derivative (PPD) skin test for healthcare workers (HCWs).

Design:

Blinded dual skin testing, using PPD and M. avium sensitin, of HCWs at a single medical center who had a 10-to 14-mm reaction to PPD when tested by personnel from the Occupational Health Department as part of routine annual screening.

Setting:

A single tertiary-care academic medical center.

Participants:

Employees of the medical center who underwent routine annual PPD screening and were identified by the Occupational Health Department as having a reaction of 10 to 14 mm to PPD.

Results:

Nineteen employees were identified as candidates and 11 underwent dual skin testing. Only 4 (36%) had repeat results for PPD in the 10- to 14-mm range, whether read by Occupational Health Department personnel or study investigators. For only 5 (45%) of the subjects did the Occupational Health Department personnel and study investigators concur (± 3 mm) on the size of the PPD reaction. Two of the 4 subjects with reactions of 10 to 14 mm as measured by the study investigators were M. avium sensitin dominant, 1 was PPD dominant, and 1 was nondominant.

Conclusion:

A reaction of 10 to 14 mm to PPD should not be used as an indication for the treatment of latent tuberculosis (TB) infection in healthy HCWs born in the United States with no known exposure to TB.

Tuberculosis in Poland in 2013

AIM OF THE STUDY

To evaluate the main features of TB epidemiology in 2013 in Poland and to compare with the corresponding EU/EEA data.

METHODS

Analysis of case- based clinical and demographic data on TB patients from Central TB Register, of data submitted by laboratories on anti-TB drug susceptibility testing results in cases notified in 2013, data from National Institute of Public Health- National Institute of Hygiene on cases of tuberculosis as AIDS-defining disease, from Central Statistical Office on deaths from tuberculosis based on death certificates, data from ECDC report "European Centre for Disease Prevention and Control/WHO Regional Office for Europe. Tuberculosis surveillance and monitoring in Europe 2015. Stockholm: European Centre for Disease Prevention and Control, 2015".

RESULTS

7250 TB cases were reported in Poland in 2013. The incidence rate was 18.8 cases per 100 000, with large variability between voivodships from 9.9 to 27.4. The mean annual decrease of TB incidence in 2009-2013 was 2.0%. 6403 cases had no history of previous treatment (rate 16.6). The number of all notified pulmonary tuberculosis cases was 6835; 17.8 per 100 000. The proportion of extrapulmonary tuberculosis among all registered cases was 5.7% (415 cases). In 2013, 34 patients had fibrous-cavernous pulmonary tuberculosis (0.5% of all cases of pulmonary tuberculosis). TB was diagnosed in 116 children (1.6% of all cases, incidence 2.0). The incidence of tuberculosis increased progressively with age to 33.7 among patients 65 years old and older. The mean age of new TB cases was 53.5 years. The incidence among men (26.8) was more than two times higher than among women (11.4). The incidence rate in rural population was lower than in urban areas; 17.1 vs. 20.0. Bacteriologically confirmed pulmonary cases (4825) constituted 68,2% of all pulmonary TB cases. The number of smear positive pulmonary TB cases was 2859 (61.3% of culture confirmed pulmonary cases). There were 52 foreigners registered among all cases of tuberculosis in Poland (0.7%) and 250 cases registered among prisoners (rate 298.0). There were 40 patients with MDR-TB (0.8% of cases with known DST results). TB was AIDS indicative disease in 35 cases. There were 630 deaths due to tuberculosis in 2012 (1.6 TB deaths per 100 000). Mortality among males--2.6--was more than 3 times higher than among females--0.8.

CONCLUSIONS

In Poland in 2013 the incidence of tuberculosis was higher than the average in EU/EEA countries. The highest incidence rates occurred in older age groups. The incidence in men was more than 2 times higher than in women. The incidence of tuberculosis in children and the percentage of patients with drug- resistant tuberculosis are lower than average in the EU/EEA and that is favorable for epidemiological situation of tuberculosis in our country.

Quality of diagnostic and treatment practices of pulmonary tuberculosis management amongst health practitioners in Haryana, north India

INTRODUCTION

Early diagnosis and supervised treatment remains the mainstay for tuberculosis (TB) control in India.

METHODS

A facility-based cross-sectional study was conducted to assess diagnostic and treatment practices of tuberculosis management as per the Revised National Tuberculosis Control Programme at a secondary level health facility in north India. This hospital mostly caters to rural and peri-urban populations in the Ballabgarh block of Faridabad district, Haryana. A sample size of 244 was calculated. Consecutive chest symptomatic patients were recruited in the study. Information about socio-demographic characteristics and treatment was obtained from a routine history-taking process in the outpatient clinic. Results were expressed as mean, standard deviation (SD) and odds ratio (OR) with 95% confidence interval (CI).

RESULTS

A total of 250 pulmonary TB suspects were recruited, out of which 55.4% were males and mean age of study participants was 35.4 years (SD 14.6). Almost half (47.1%) of the participants had sought treatment from government hospitals, followed by 46.7% from private hospitals. Those who had visited a private facility were significantly more likely not to receive sputum acid-fast bacillus (AFB) diagnostic testing (OR=7.26, 95% CI 4.04-13.08), likely to be taking a second-line anti-TB drug as an antibiotic trial (OR=3.65, 95% CI 1.17-11.30), be empirically taking anti-TB drugs (OR=5.28, 95% CI 1.50-118.64) and getting a serological test done (OR=9.58, 95% CI 1.20-76.0) than those who went to a government health facility. Those who made at least three visits to a private facility were significantly more likely to have taken a second-line anti-TB drug as an antibiotic trial (OR=3.56, 95% CI 1.36- 9.28) and be empirically taking anti-TB drugs (OR=5.75, 95% CI 2.18-15.20) than those that made fewer than three visits.

CONCLUSIONS

This study documented inappropriate diagnostic and treatment practices in TB management and highlights the need to generate awareness about it among health practitioners in north India.

T-CELL RESPONSES ASSESSED USING IGRA AND TST ARE NOT CORRELATED WITH AFB GRADE AND CHEST RADIOGRAPH IN PULMONARY TUBERCULOSIS PATIENTS

A definitive marker determining the bacillary load of Mycobacterium tuberculosis (MTB), the causative agent of tuberculosis (TB), and hence disease severity, is required for patient monitoring and management. In this study, the association among T-cell responses based on the interferon-gamma release assay (IGRA) and the tuberculin skin test (TST), the sputum acid-fast bacilli (AFB) grade and types of radiological lesions were analyzed in new cases of pulmonary TB patients (n = 54) at Srinagarind Hospital, Khon Kaen, Thailand between September 1, 2012 and March 31, 2014. It was found that infiltrative and cavitary lesions from chest radiographs were associated with high sputum AFB grade (p = 0.048). T-cell responses from both IGRA and TST were not correlated with sputum AFB grade. Neither IGRA nor TST was correlated with the bacillary load as defined by AFB grade and chest radiographs. Patients with cavitary lesions on chest radiographs tended to have high IFN-γ concentrations and large TST indurations. In addition, TB patients with previous BCG vaccination showed significantly higher IFN-γ induction compared to the non-vaccinated group (p = 0.001). This study showed T-cell responses based on both IGRA and TST were not correlated with AFB grade and chest radiograph. In areas of high rates of BCG vaccination, as in Thailand, the BCG may affect IGRA and TST interpretations.

Comparison of interferon-γ release assay to two cut-off points of tuberculin skin test to detect latent Mycobacterium tuberculosis infection in primary health care workers

BACKGROUND

An interferon-γ release assay, QuantiFERON-TB (QFT) test, has been introduced an alternative test for the diagnosis of latent Mycobacterium tuberculosis infection (LTBI). Here, we compared the performance of QFT with tuberculin skin test (TST) measured at two different cut-off points among primary health care work (HCW) in Brazil.

METHODS

A cross-sectional study was carried out among HCWs in four Brazilian cities with a known history of high incidence of TB. Results of the QFT were compared to TST results based on both ≥5 mm and ≥10 mm as cut-off points.

RESULTS

We enrolled 632 HCWs. When the cut-off value of ≥10 mm was used, agreement between QFT and TST was 69% (k = 0.31), and when the cut-off of ≥5 mm was chosen, the agreement was 57% (k = 0.22). We investigated possible factors of discordance of TST vs QFT. Compared to the TST-/QFT- group, risk factors for discordance in the TST+/QFT- group with TST cut-off of ≥5 mm included age between 41-45 years [OR = 2.70; CI 95%: 1.32-5.51] and 46-64 years [OR = 2.04; CI 95%: 1.05-3.93], BCG scar [OR = 2.72; CI 95%: 1.40-5.25], and having worked only in primary health care [OR = 2.30; CI 95%: 1.09-4.86]. On the other hand, for the cut-off of ≥10 mm, BCG scar [OR = 2.26; CI 95%: 1.03-4.91], being a household contact of a TB patient [OR = 1.72; CI 95%: 1.01-2.92] and having had a previous TST [OR = 1.66; CI 95%: 1.05-2.62], were significantly associated with the TST+/QFT- group. No statistically significant associations were found among the TST-/QFT+ discordant group with either TST cut-off value.

CONCLUSIONS

Although we identified BCG vaccination to contribute to the discordance at both TST cut-off measures, the current Brazilian recommendation for the initiation of LTBI treatment, based on information gathered from medical history, TST, chest radiograph and physical examination, should not be changed.

Poor agreement between QuantiFERON-TB Gold test and tuberculin skin test results for the diagnosis of latent tuberculosis infection in rheumatoid arthritis patients and healthy controls

BACKGROUND/AIMS

We investigated the agreement between the QuantiFERON-TB Gold (QFT-Gold) test and the tuberculin skin test (TST) in the diagnosis of latent tuberculosis infection in patients with rheumatoid arthritis (RA), compared with healthy controls, in Korea.

METHODS

We recruited 64 patients with RA and 79 healthy controls at two university hospitals in South Korea. The participants underwent both the QFT-Gold test and the TST simultaneously between August 2006 and February 2009. All patients were diagnosed using the classification criteria for RA revised in 1987 by the American College of Rheumatology. Bacillus Calmette-Guérin vaccination status and current medications were evaluated, and disease activities were assessed using the Disease Activity Score in 28 joints. Eleven patients with RA produced indeterminate QFT-Gold test results and were thus excluded from the kappa analysis.

RESULTS

Based on an induration of 10 mm in diameter as the TST cutoff value, the QFT-Gold test and TST demonstrated 75.0% agreement (κ = 0.23) in patients with RA and 75.9% agreement (κ = 0.19) in healthy controls. Among the 56 patients with RA who had negative TST results, 11 patients (17.2%) also yielded indeterminate QFT-Gold results.

CONCLUSIONS

Our study showed poor agreement between the results of the QFT-Gold test and the TST in both RA patients and healthy controls. Based on these findings, we emphasize the importance of making clinical decisions in the diagnosis of latent tuberculosis in Koreans with or without RA.

Interferon γ in patients with HIV/AIDS and suspicion or latent tuberculosis infection

OBJECTIVE

To assess the usefulness of IGRA test (QuantiFERON(®)-Cell mediated immune) compared with the tuberculin skin test.

METHODS

A cross-sectional study was carried out in Mexico, 25 infected patients with HIV-AIDS and the suspicion or with latent tuberculous infection (LTBI) who were >18 years of age and without treatment for tuberculosis (TB), were enrolled in the study.

RESULTS

Median cluster of differentiation (CD4) count was 364 cells/μ L and median HIV viral load was 50 copies/mL. Overall, 20 patients (80%) had at least one positive diagnostic test for LTBI: four (16%) had a positive tuberculin skin test and 19 (76%), a positive QuantiFERON(®)-tuberculosis.

CONCLUSIONS

No agreement is found between the two diagnostic tests: k = -0.004, 95% confidence interval (-0.2219, 0.2210). Additional longitudinal studies among HIV-infected populations with high prevalence of TB are needed to further assess the usefulness of IGRAs in this patient population.

Tuberculosis in Poland in 2011

AIM OF THE STUDY

To evaluate the main features of TB epidemiology in 2011 in Poland and to compare with the corresponding EU data.

METHODS

Analysis of case- based clinical and demographic data on TB patients from Central TB Register, of data submitted by laboratories on anti-TB drug susceptibility testing results in cases notified in 2011, data from National Institute of Public Health- National Institute of Hygiene on cases of tuberculosis as AIDS-defining disease, from Central Statistical Office on deaths from tuberculosis based on death certificates, data from ECDC report "Tuberculosis surveillance in Europe 2011".

RESULTS

8478 TB cases were reported in Poland in 2011. The incidence rate was 22.2 cases per 100,000, with large variability between voivodeships from 12.8 to 37.0. The mean annual decrease of TB incidence in 2007 - 2011 was 0.4%. 7515 cases had no history of previous treatment i.e. 19.7 per 100,000. The number of all notified pulmonary tuberculosis cases was 7879 i.e. 20.6 per 100,000. The proportion of extrapulmonary tuberculosis was 7.1% (599 cases). TB was diagnosed in 111 children (1.3% of all cases, incidence 1.9). The incidence of tuberculosis increased with age to 41.9 among patients 65 years old and older. The mean age of TB patients was 53.3 years. The incidence among men i.e. 31.0 was more than two times higher than among women i.e. 14.0. The incidence in rural population was slightly lower than in urban, respectively 21.9 and 22.4. Bacteriologically confirmed cases (5327) constituted 67.6% of all pulmonary TB cases. The number of smear positive pulmonary TB cases was 2916 (37.0% of all pulmonary cases). There were 38 foreigners registered among all cases of tuberculosis in Poland and 204 cases registered among prisoners. There were 41 patients with MDR-TB (0.8% of 4993 cases with DST results). TB was initial AIDS indicative disease in 26 cases. There were 575 deaths due to tuberculosis in 2010 (1.5 TB deaths per 100,000). Mortality among males--2.5--was four times higher than among females--0.6.

CONCLUSIONS

In Poland the incidence of tuberculosis is higher than the average in EU countries. In 2011 the highest incidence occurred in older age groups and was higher in men. Positive characteristic also when compared with the situation in many EU countries is the low incidence of tuberculosis in children and the low percentage of patients with drug-resistant tuberculosis.

Identifying predictors of interferon-γ release assay results in pediatric latent tuberculosis: a protective role of bacillus Calmette-Guerin?: a pTB-NET collaborative study

RATIONALE

Interferon-γ (IFN-γ) release assays are widely used to diagnose latent infection with Mycobacterium tuberculosis in adults, but their performance in children remains incompletely evaluated to date.

OBJECTIVES

To investigate factors influencing results of IFN-γ release assays in children using a large European data set.

METHODS

The Pediatric Tuberculosis Network European Trials group pooled and analyzed data from five sites across Europe comprising 1,128 children who were all investigated for latent tuberculosis infection by tuberculin skin test and at least one IFN-γ release assay. Multivariate analyses examined age, bacillus Calmette-Guérin (BCG) vaccination status, and sex as predictor variables of results. Subgroup analyses included children who were household contacts.

MEASUREMENTS AND MAIN RESULTS

A total of 1,093 children had a QuantiFERON-TB Gold In-Tube assay and 382 had a T-SPOT.TB IFN-γ release assay. Age was positively correlated with a positive blood result (QuantiFERON-TB Gold In-Tube: odds ratio [OR], 1.08 per year increasing age [P < 0.0001]; T-SPOT.TB: OR, 1.14 per year increasing age [P < 0.001]). A positive QuantiFERON-TB Gold In-Tube result was shown by 5.5% of children with a tuberculin skin test result less than 5 mm, by 14.8% if less than 10 mm, and by 20.2% if less than 15 mm. Prior BCG vaccination was associated with a negative IFN-γ release assay result (QuantiFERON-TB Gold In-Tube: OR, 0.41 [P < 0.001]; T-SPOT.TB: OR, 0.41 [P < 0.001]). Young age was a predictor of indeterminate IFN-γ release assay results, but indeterminate rates were low (3.6% in children < 5 yr, 1% in children > 5 yr).

CONCLUSIONS

Our data show that BCG vaccination may be effective in protecting children against Mycobacterium tuberculosis infection. To restrict use of IFN-γ release assays to children with positive skin tests risks underestimating latent infection.

The role of interferon-gamma release assays in the diagnosis of active tuberculosis

BACKGROUND

Interferon-gamma release tests are appealing alternatives to the tuberculin skin test (TST) for latent tuberculosis infection.

OBJECTIVES

To determine the yield of the Quantiferon TB Gold test (QFT-G) in the diagnosis of active tuberculosis disease, with a focus on elderly patients, human immunodeficiency virus (HIV) co-infection, and extra-pulmonary tuberculosis (EPTB).

METHODS

The QFT-G test was performed in 98 patients suspected of having active tuberculosis. The results were evaluated for each subgroup of patients and compared to the results of the TST.

RESULTS

Active tuberculosis was diagnosed in 92 of the 98 patients. Sixteen (17.3%) were elderly patients (over age 70), 15 (16%) were co-infected with HIV, and 14 (15%) had EPTB. QFT-G was positive in 49 patients (53%) and indeterminate in 4. The results were not significantly affected by HIV coinfection (P = 0.17), old age (P = 0.4), orthe presence of EPTB (P = 0.4). There was a good correlation between the TST and the QFT-G test (P < 0.001). In EPTB and in the elderly, the QFT-G test appears to be better than the TST.

CONCLUSIONS

The QFT-G test is suboptimal in its ability to detect active tuberculosis and should not be used to exclude it.

[Tuberculosis in Poland in 2010]

AIM OF THE STUDY

To evaluate the main features of TB epidemiology in 2010 in Poland and to compare with the corresponding EU data.

METHODS

Analysis of case- based clinical and demographic data on TB patients from Central TB Register, of data submitted by laboratories on anti-TB drug susceptibility testing in cases notified in 2010, data from National Institute of Public Health- National Institute of Hygiene on cases of tuberculosis as AIDS-defining disease, from Central Statistical Office on tuberculosis as underlying cause of death based on death certificates, data from ECDC report "Tuberculosis surveillance in Europe 2010".

RESULTS

7509 TB cases were reported in Poland in 2010. The incidence rate was 19.7 cases per 100000, with large variability between voivodeships from 12,8 to 31.9. The mean annual decrease of TB incidence in 2001 - 2010 was 2.9%. 6610 cases had no history of previous treatment i.e. 17.3 per 100000. The number of all notified pulmonary tuberculosis cases was 6992 i.e. 18.3 per 100 000. The proportion ofextrapulmonary tuberculosis was 6.9% (517 cases). TB was diagnosed in 62 children (0.8% of all cases, incidence 1,1). The incidence of tuberculosis increased with age to 34.9 among patients 65 years old and older. The mean age of TB patients was 52.7 years. The incidence among men i.e. 28.0 was more than two times higher than among women i.e. 11.9. The incidence in rural population was slightly lower than in urban, respectively 19.4 and 19.8. Bacteriologically confirmed cases (4585) constituted 65.6% of all pulmonary TB cases. The number of smear positive pulmonary TB cases was 2803 (40.1%). There were 45 cases of tuberculosis registered among foreigners and 215 cases registered among prisoners. There were 30 patients with MDR-TB (0.8% of 3706 cases with DST results). TB was initial AIDS indicative disease in 24 cases. There were 743 deaths due to tuberculosis in 2009 (2.0 TB deaths per 100 000). Mortality among males--3.2--was four times higher than among females--0.8.

CONCLUSIONS

In Poland in the last decade the incidence of tuberculosis has decreased by nearly 30% but is higher than the average in EU countries. In 2010 the highest incidence occurred in older age groups and was higher in men. Positive characteristic also when compared with the situation in many EU countries is the low incidence of tuberculosis in children and the low percentage of patients with drug-resistant tuberculosis.

[Socio-economic status and duration of TB symptoms in males treated at the Mazovian Treatment Centre of Tuberculosis and Lung Diseases in Otwock]

INTRODUCTION

The incidence of tuberculosis depends on many factors, not only on health issues but also on socioeconomic factors. The aim of this study was to assess the duration of symptoms and the extent of radiological changes in men with bacteriologically confirmed pulmonary tuberculosis in relation to their socioeconomic status.

MATERIAL AND METHODS

This was a retrospective study based on the analysis of 300 hospital records of patients hospitalised in 2004-2006 in the male ward of the Mazovian Treatment Centre of Lung Diseases and Tuberculosis in Otwock. In all patients, the diagnosis of tuberculosis was bacteriologically confirmed. We evaluated the duration of symptoms prior to hospitalisation, the extent of radiological changes and socioeconomic status. We also took into account the place of residence, professional activity, age and marital status.

RESULTS

Among patients with TB hospitalised in the Mazovia Region, 74% were professionally inactive persons and 57% were unemployed. Patients population in cities and villages were similar, but as much as 10% of the patients hospitalised who were actively spreading bacilli in Mazovia Region were homeless. In the study group, 60% of the men were unmarried. In 63% of the patients symptoms of tuberculosis were present for more than two months. Chronic symptoms were reported more often in the unemployed (60%) and in single patients. As much as 81% of the patients at the initiation of treatment, had extensive radiological changes in 3 or more lung fields. Quite often sweeping pulmonary changes were observed in the homeless, unemployed and pensioners. Sputum smear-positive tuberculosis, was demonstrated in 87% of the examined patients.

CONCLUSIONS

The incidence of tuberculosis observed in the Mazovia Region was especially observed in the unemployed, disabled and pensioners. Among these patients, many were homeless. The majority of patients in Mazovia Region at the start of treatment already had very extensive radiological changes and the symptoms were present with them for several weeks.

Immunosurveillance for Mycobacterium tuberculosis of health care personnel in a third level care hospital

BACKGROUND

Health care workers are at risk for Mycobacterium tuberculosis (MTB) infection.

OBJECTIVES

To perform an occupational health survey among 621 employees of a 800-bed third level care hospital covered by MTB surveillance.

METHODS

Statistical analysis was applied to results from tuberculin skin test (TST), QuantiFERON - TB Gold in tube assay (QFT), PPD-ELISA for serum antibodies, and occupational or vaccine data.

RESULTS

29.1% of subjects were TST positive, 18.5% were QFT positive. In 23% of subjects no correlation between these tests was found, presumably linked to BCG-vaccination, since TST positivity was 4 times higher among vaccinated subjects, whereas both tests correlated well in unvaccinated subjects. QFT values above 2 IU/ml were significantly associated with positive TST and age over 40 years. Working in MTB risk level 4 was significantly associated with QFT, TST and PPD-antibody levels, suggesting booster effects by repeated exposure. No clear correlation was observed with medical specializations but significantly higher QFTpositivity was found in subjects not assigned to the classical medical professions and originating from MTB high risk areas.

CONCLUSIONS

These results shift the focus on maintenance personnel, who mostly worked in MTB risk level 2 areas. The less positive QFT results in vaccinated subjects highlight QFT's advantage as a screening tool and argue for a protective effect of the BCG-vaccine, although percentages of vaccinated persons varied largely between different medical professions. Interestingly, the percentage of QFT positive persons was lower among subjects reporting MTB exposure than those who were not aware of exposure events.

High annual risk of tuberculosis infection among nursing students in South India: a cohort study

Background

Nurses in developing countries are frequently exposed to infectious tuberculosis (TB) patients, and have a high prevalence of TB infection. To estimate the incidence of new TB infection, we recruited a cohort of young nursing trainees at the Christian Medical College in Southern India. Annual tuberculin skin testing (TST) was conducted to assess the annual risk of TB infection (ARTI) in this cohort.

Methodology/Principal Findings

436 nursing students completed baseline two-step TST testing in 2007 and 217 were TST-negative and therefore eligible for repeat testing in 2008. 181 subjects completed a detailed questionnaire on exposure to tuberculosis from workplace and social contacts. A physician verified the questionnaire and clinical log book and screened the subjects for symptoms of active TB. The majority of nursing students (96.7%) were females, almost 84% were under 22 years of age, and 80% had BCG scars. Among those students who underwent repeat testing in 2008, 14 had TST conversions using the ATS/CDC/IDSA conversion definition of 10 mm or greater increase over baseline. The ARTI was therefore estimated as 7.8% (95%CI: 4.3–12.8%). This was significantly higher than the national average ARTI of 1.5%. Sputum collection and caring for pulmonary TB patients were both high risk activities that were associated with TST conversions in this young nursing cohort.

Conclusions

Our study showed a high ARTI among young nursing trainees, substantially higher than that seen in the general Indian population. Indian healthcare providers and the Indian Revised National TB Control Programme will need to implement internationally recommended TB infection control interventions to protect its health care workforce.

An evaluation of factors associated with taking and responding positive to the tuberculin skin test in individuals with HIV/AIDS

BACKGROUND

The tuberculin skin test (TST) is still the standard test for detecting latent infection by M tuberculosis (LTBI). Given that the Brazilian Health Ministry recommends that the treatment of latent tuberculosis (LTBI) should be guided by the TST results, the present study sets out to describe the coverage of administering the TST in people living with HIV at two referral health centers in the city of Recife, where TST is offered to all patients. In addition, factors associated with the non-application of the test and with positive TST results were also analyzed.

METHODS

A cross-sectional study was carried out with HIV patients, aged 18 years or over, attending outpatient clinics at the Correia Picanço Hospital/SES/PE and the Oswaldo Cruz/UPE University Hospital, who had been recommended to take the TST, in the period between November 2007 and February 2010. Univariate and multivariate logistic regression analyses were carried out to establish associations between the dependent variable - taking the TST (yes/no), at a first stage analysis, and the independent variables, followed by a second stage analysis considering a positive TST as the dependent variable. The odds ratio was calculated as the measure of association and the confidence interval (CI) at 95% as the measure of accuracy of the estimate.

RESULTS

Of the 2,290 patients recruited, 1087 (47.5%) took the TST. Of the 1,087 patients who took the tuberculin skin test, the prevalence of TST ≥ 5 mm was 21.6% among patients with CD4 ≥ 200 and 9.49% among those with CD4 < 200 (p = 0.002). The patients most likely not to take the test were: men, people aged under 39 years, people with low educational levels and crack users. The risk for not taking the TST was statiscally different for health service. Patients who presented better immunity (CD4 ≥ 200) were more than two and a half times more likely to test positive that those with higher levels of immunodeficiency (CD4 < 200).

CONCLUSIONS

Considering that the TST is recommended by the Brazilian health authorities, coverage for taking the test was very low. The most serious implication of this is that LTBI treatment was not carried out for the unidentified TST-positive patients, who may consequently go on to develop TB and eventually die.

Tuberculosis transmission in Kenya: results of the third National Tuberculin Survey

SETTING

Kenya, a country with a high burden of tuberculosis (TB) and human immunodeficiency virus (HIV) infection.

OBJECTIVES

To assess the prevalence of TB infection, bacille Calmette-Guérin (BCG) coverage and the annual risk of tuberculosis infection (ARTI), and to compare estimates with previous findings.

METHODS

A sample of primary school children aged 6-14 years from the same study districts sampled in previous surveys were tuberculin skin tested using the Mantoux method from September 2004 to July 2007. The prevalence of TB infection was estimated by the mirror method, with the mode at 17 mm.

RESULTS

Of the 94 771 registered children, 76 676 (80.9%) completed the survey investigations, 12 107 (15.8%) of whom had no BCG scar. The prevalence of TB infection was estimated at 10.2%, with a corresponding ARTI of 1.1%. The ARTI obtained from the current survey is comparable to that of the 1994-1996 survey and higher than that of the 1986-1990 survey. The BCG coverage was comparable with the 1994-1996 survey and higher than in the 1986-1990 survey.

CONCLUSION

TB transmission in Kenya has remained the same over the last decade, which suggests that activities undertaken by the TB control programme have been sufficient to hold TB transmission steady, but insufficient to reduce it.

Use of the QuantiFERON-TB Gold test to confirm latent tuberculosis infection in a Canadian tuberculosis clinic

SETTING

Capital Health Tuberculosis (TB) Clinic, Edmonton, Alberta, Canada.

OBJECTIVE

To analyze the QuantiFERON-TB Gold In-Tube test (QFT) results after implementation as a routine test for tuberculin skin test (TST) positive patients.

DESIGN

From November 2004 until January 2007, patients who were TST-positive and were eligible for preventive treatment based on Canadian guidelines, were offered a QFT.

RESULTS

Of 1446 TST-positive patients, only 566 (39.6%) were QFT-positive. Categorized by reason for TST testing, 43.1% of 304 contacts, 32.8% of 348 employment screens and 24.2% of 298 post secondary school screens were QFT-positive. In contrast, 59.7% of 290 immigration screens were QFT-positive. A multivariate analysis found that QFT positivity was associated with older age, larger TST size, high-incidence TB region of birth, history of TB and chest X-ray findings suggestive of previous TB.

CONCLUSION

Implementation of the QFT as a secondary test for latent TB infection (LTBI) can significantly reduce the number of patients given LTBI treatment in a low-incidence country such as Canada.

Interpretation of a serial Mantoux test taking into account the annual risk of tuberculous infection

BACKGROUND

Interpretation of tuberculin tests (TSTs) can be difficult. However, it is even more difficult to classify an individual as infected or non-infected if he or she has undergone a prior TST, as the difference between the booster effect and true conversion is not always clear.

OBJECTIVE

To determine the size of the induration that is indicative of true infection after a second Mantoux test, based on the fact that the annual risk of tuberculous infection (ARTI) is equivalent, regardless of whether it is calculated directly or indirectly.

METHOD

We performed two TSTs in the same population (aged 6 years at the first examination) with a 1-year interval. We calculated the prevalence of infection the first year (1.16%, 95%CI 0.67-1.65) and the ARTI using the indirect method (0.18%, 95%CI 0.00-0.37). For the second year, we considered different induration sizes and finally accepted a diameter of >10 mm as the criterion according to which the ARTI, calculated directly, corresponded to the value of the previous year (0.18%).

CONCLUSION

Although they served as an aid in the interpretation of the TST, calculations of this type will probably be unnecessary in the future, when in vitro diagnostic tests for tuberculosis are made available in every health centre, thus enabling the classification of those individuals with indurations of intermediate size in the TST.

Prevalence of tuberculous infection among school children in Kerala

BACKGROUND

There is paucity of information on epidemiological situation of Tuberculosis (TB) in the State of Kerala. The DOTS strategy under the Revised National Tuberculosis Control Programme (RNTCP) was introduced in the year 1998 to cover the entire State by 2002.

OBJECTIVE

To estimate the prevalence of tuberculous infection among children attending 1-4th standard in a sample of selected schools in Kerala.

METHODS

A cluster-sample school-based tuberculin survey was carried out in 70 schools selected by a two-stage sampling procedure. A total of 4821 children (including those with and without BCG scar) in the age group of 5-9 years were tuberculin tested using 1 TU PPD RT23 with Tween 80 and the maximum transverse diameter of induration was measured about 72 hours later. About 81% of the children were found to have BCG scars. Analysis was also undertaken by mixture model.

RESULTS

While 67% of children without BCG scar and 62% with scar did not elicit any induration at the test site, the mode or anti-mode of reactions due to infection with tubercle bacilli could not be identified from the distribution graphs. Analysis by mixture model also did not provide the best fit thus precluding estimation of prevalence of infection. About 5% of children had reactions > or =10 mm, 3% had reactions > or =12 mm and 2% had reactions > or =14 mm.

CONCLUSION

Low proportion of reactors indicated a low level of transmission of infection in Kerala. Considering the problems in interpretation of tuberculin survey data, it may not be feasible to use ARTI as an epidemiological parameter to monitor future trends of TB situation in the state.

Annual risk of tuberculosis infection in Chennai city

AIM

To study the proportion of children infected with Mycobacterium Tuberculosis in Chennai city.

METHODOLOGY

A cluster sampling methodology was adopted to select an estimated sample size of 7000 children from five corporation zones selected systematically from ten zones of the city. A total of 7098 children aged 1-9 years were subjected to Mantoux and test read; 1897 (27%) from slum area and 5201 (73%) from non-slum area.

RESULTS

The prevalence of infection among children without BCG scar was estimated to be 10.5 % (ARTI of 2.0%) and was similar to that among children irrespective of scar status. The prevalence of infection was higher among children in slum areas (11.1%; ARTI 2.1%) compared to non-slum areas (8.9%; ARTI 1.7%); but the difference was not statistically different.

CONCLUSION

The tuberculosis situation in Chennai as measured by risk of infection was higher in urban city area than rural areas and comparable to that found in other cities as reported from earlier studies. This information can be used as baseline information for monitoring the epidemiological trends in Chennai city in future.

Clinico-radiological profile of new smear positive pulmonary tuberculosis cases among young adult and elderly people in a tertiary care hospital at Deheradun (Uttarakhand)

SETTING

Patients of pulmonary tuberculosis (TB) attending the out and in patient department of pulmonary medicine, Himalayan Institute of Medical Sciences (HIMS), a post graduate institute and a large tertiary care center in Dehradun.

OBJECTIVE

To compare the clinico-radiological pattern of pulmonary tuberculosis in the young adult (18-59 years) and elderly (> or = 60 years) patients.

DESIGN

Prospective observational study of pulmonary and associated extra pulmonary tuberculosis cases, diagnosed between October 2005 to September 2006 in pulmonary medicine department of HIMS.

RESULT

Mean age of young adult and elderly patients was 35.71 +/- 5.7 years and 68.57 +/- 3.03 years respectively. Elderly patients had a higher number of co-morbidities like diabetes mellitus, hypertension, and malignancy. Tuberculin positivity was less among elderly patients (36.0%) as compared to young adults (65.9%). Hemoptysis (29.5% vs. 6%), fever (95.4% vs. 76%) and night sweats (54.5% vs. 18.0%) were significantly higher in the young adult patients than the elderly. As for roentgenographic abnormalities, a higher involvement of lower zone (24.0% vs. 7.9%) and far advanced lesions (32.0% vs. 14.7%) were seen in the elderly patients as compared to young adults. The elderly showed a higher frequency of TB related mortality (8% vs. 1.1%) and associated extra pulmonary involvement (40% vs. 7%).

CONCLUSION

Young adults are more likely to have hemoptysis, night sweats and positive PPD response while lower lung field involvement is more common in elderly.

Prevalence of positive tuberculin skin tests in foreign-born children

AIMS

To evaluate the prevalence of positive tuberculin skin tests (TST) in internationally adopted and immigrant children. To identify risk factors for positive TST in these populations.

METHODS

The study was a retrospective medical record review in a tertiary care pediatric hospital. All children evaluated at the International Adoption and Immigrant Health Clinic of CHU Sainte-Justine in Montreal, Canada, between 01-01-1998 and 31-12-2001 were included. Demographic and anthropometrical data, BCG vaccination, TST, chest X-ray results and treatment were extracted from the medical records of the patients and analyzed. Positive TST was defined as induration = 10 mm, 48 to 72 hours after injection of five tuberculin units of purified protein derivate.

RESULTS

Our population included 670 children: 112 immigrants and 558 adoptees. Median age was 6.9 years for immigrants and 1.1 years for adopted children. Overall incidence of positive TST was 12.2% in our cohort: 31% in the immigrant and 8% in the adopted children groups. There was one case of active tuberculosis. Older age on arrival in Canada and BCG vaccination were identified as risk factors for positive TST in our multivariate model. For each one-year increase in age on arrival in Canada, there was a 1.2 times greater risk for positive TST.

CONCLUSIONS

Latent tuberculosis is a frequent problem in foreign-born children. The higher incidence in immigrant children can be explained by older age on arrival.

Reliability of control skin tests with common antigens in children undergoing tuberculin skin test

The aim of this study was to determine the reliability of skin tests with common antigens as a measure of delayed-type hypersensitivity response in children undergoing tuberculin skin test (TST). Children from developing countries underwent TST as well as skin tests with diphtheria-tetanus vaccine (DT) and candida antigens prior to heart surgery. We included 52 children (mean age: 7.16 years). Forty-two (81%) and 20 of the 52 patients (38%) reacted to the DT and candida skin tests, respectively (P < 0.001 for the difference in response to these antigens). There was no difference in response to candida and DT antigens between patients with positive or negative TST. There was no difference between patients aged 6 years or older compared to younger patients in the response to DT or candida antigen. Skin tests with common antigens are associated with a high false-negative rate and may not predict reliably a state of anergy.

The effect of open heart surgery on tuberculin skin test reactivity

To examine whether treatment with cardiopulmonary bypass (CPB), which causes transient cellular immunity depression, influences tuberculin skin testing (TST) interpretation. The study was also aimed to assess the degree of cellular immunity depression following open heart surgery. Fifteen children from developing countries with latent tuberculosis (TST >or=10 mm), undergoing open heart surgery had their TST repeated within 48-72 h following surgery. We compared the size of skin test induration before and after surgery and the relation of postsurgery skin induration to time on CPB (pump time). There was no significant difference in the size of induration before and after surgery (mean: 14.7 mm versus 13 mm, respectively). Pump time ranged from 38 to 204 min (mean: 110 min). Two of the children had pump time over 3 h. The TST of both of them turned negative after surgery, as opposed to all other children (P = 0.01). Most patients retained skin test reactivity. Only patients with pump time longer than 3 h had a negative TST.

Tuberculin skin test size and risk of tuberculosis development: a large population-based study in contacts

SETTING

Contacts of tuberculosis (TB) cases identified from eight Provincial databases in British Columbia, Canada, between 1990 and 2000.

OBJECTIVE

To assess the risk of developing TB based on tuberculin skin test (TST) sizes in contacts of TB cases who did not receive treatment for latent TB infection.

DESIGN

Retrospective, population-based cohort study with a 12-year follow-up.

RESULTS

Among 26,542 contacts, 180 individuals developed TB (TB rate 678/100,000). Household contacts with a TST size 0-4 mm had a TB rate of 1014/100,000, those with 5-9 mm a TB rate of 2162/100,000 and those with 10-14 mm a rate of 4478/100,000. Children aged 0-10 years with 0-4 mm had a TB rate of 806/100,000, those with 5-9 mm a TB rate of 5556/100,000 and those with 10-14 mm a rate of 42,424/100,000. Immunosuppressed contacts with TST sizes 0-4 mm had a TB rate of 630/100,000, those with 5-9 mm a TB rate of 1923/100,000, and those with 10-14 mm a rate of 1770/100,000.

CONCLUSIONS

TB rates were high for all TST sizes in household contacts, 0-10 year old contacts and immunosuppressed contacts. These contacts may benefit from treatment for latent TB infection, regardless of the size of their TST.

Risk factors for positive tuberculin skin test in Guinea-Bissau

BACKGROUND

The tuberculin skin test is used for tracing of tuberculosis transmission and identifying individuals in need of prophylactic treatment.

METHODS

Using a case-control study design, we recruited 220 smear-positive tuberculosis cases and 223 randomly selected healthy community controls in Bissau, Guinea-Bissau, during 1999-2000. Tuberculin skin tests were performed on family members of cases and controls (n = 1059 and n = 921, respectively). Induration of 10 mm or greater was considered positive. Risk factors were calculated for children (<15 years) and adults separately in multivariate logistic regression analysis.

RESULTS

The prevalence of positive tuberculin skin test was 41% in case-contacts compared with 22% in control-contacts, resulting in a prevalence ratio of 1.48 (95% confidence interval = 1.37-1.60). Positive skin tests among case-contacts increased with age for children, as well as with proximity to a case during the night, for both children and adults. A Bacille Calmette Guerin scar increased the likelihood of having a positive tuberculin skin test for adults in case households, but not in other categories of contacts. Among control-contacts the prevalence of positive skin test was associated with older age in children, history of tuberculosis in the family, and a positive tuberculin skin test of the control person.

CONCLUSIONS

Risk factors for a positive tuberculin skin test among case- and control-contacts are closely related to tuberculosis exposure. Having a BCG scar did not increase the risk of positive skin test in unexposed individuals. Tuberculin skin testing remains a useful tool for diagnosing tuberculosis infection.

Tuberculin testing to detect latent tuberculosis in developing countries

Despite the multiple studies done over several decades that have established the utility of the tuberculin skin test (TST) for the diagnosis of latent tuberculosis, the test is rarely used in developing countries experiencing a resurgence of tuberculosis. Nevertheless, several clinical trials have found that treatment of HIV-positive or HIV-negative persons with latent tuberculosis is effective in the prevention of the clinical activation of tuberculosis. Clinicians commonly justify their failure to diagnose and treat latent tuberculosis with the belief that BCG vaccine, even when it is used in infancy, will cause false positive reactivity in the TST. The important study by Gustafson and colleagues from Guinea-Bissau in this issue of the journal refutes this belief. In this study only persons with a history of BCG who also had household contact with an active case of tuberculosis had increased rates of TST positivity. Although the current emphasis is on directly observed therapy, short course (DOTS) to control tuberculosis is necessary and critically important, it is not always sufficient to control the tuberculosis epidemic in some countries with major epidemics of HIV. In many of these countries, early diagnosis of active tuberculosis and prevention of activation of latent tuberculosis will also be needed. The evidence from the Guinea-Bissau study suggests that a history of BCG vaccination should not be an obstacle to the diagnosis and treatment of latent tuberculosis.

Educational outreach to promote screening for tuberculosis in primary care: a cluster randomised controlled trial

BACKGROUND

Tuberculosis is re-emerging as an important health problem in industrialised countries. Uncertainty surrounds the effect of public-health control options. We therefore aimed to assess a programme to promote screening for tuberculosis in a UK primary health care district.

METHODS

In a cluster randomised controlled trial, we randomised 50 of 52 (96%) eligible general practices in Hackney, London, UK, to receive an outreach programme that promoted screening for tuberculosis in people registering in primary care, or to continue with usual care. Screening was verbal, and proceeded to tuberculin skin testing, if appropriate. The primary outcome was the proportion of new cases of active tuberculosis identified in primary care. Analyses were done on an intention-to-treat basis. This study was registered at clinicaltrials.gov, number NCT00214708.

FINDINGS

Between June 1, 2002, and Oct 1, 2004, 44,986 and 48,984 patients registered with intervention and control practices, respectively. In intervention practices 57% (13,478 of 23,573) of people attending a registration health check were screened for tuberculosis compared with 0.4% (84 of 23 051) in control practices. Intervention practices showed increases in the diagnosis of active tuberculosis cases in primary care compared with control practices (66/141 [47%] vs 54/157 [34%], odds ratio (OR) 1.68, 95% CI 1.05-2.68, p=0.03). Intervention practices also had increases in diagnosis of latent tuberculosis (11/59 [19%] vs 5/68 [9%], OR 3.00, 0.98-9.20, p=0.055) and BCG coverage (mean BCG rate 26.8/1000 vs 3.8/1000, intervention rate ratio 9.52, 4.0-22.7, p<0.001).

INTERPRETATION

Our educational intervention for promotion of screening for tuberculosis in primary care improved identification of active and latent tuberculosis, and increased BCG coverage. Yield from screening was low, but was augmented by improved case-finding. Screening programmes in primary care should be considered as part of tuberculosis control initiatives in industrialised countries.

Nursing and Community Rates of Mycobacterium tuberculosis Infection among Students in Harare, Zimbabwe

BACKGROUND

African hospitals have experienced major increases in admissions for tuberculosis, but they are ill-equipped to prevent institutional transmission. We compared institutional rates and community rates of tuberculin skin test (TST) conversion in Harare, Zimbabwe.

METHODS

We conducted a cohort study of TST conversion 6, 12, and 18 months into training among 159 nursing and 195 polytechnic school students in Harare. Students had negative TST results (induration diameter, < or =9 mm) with 2-step testing at the start of training.

RESULTS

Nursing students experienced 19.3 TST conversions (increase in induration diameter, > or =10 mm) per 100 person-years (95% confidence interval [CI], 14.2-26.2 conversions per 100 person-years), and polytechnic school students experienced 6.0 (95% CI, 3.5-10.4) conversions per 100 person-years. The rate of difference was 13.2 conversions (95% CI, 6.5-20.0) per 100 person-years. With a more stringent definition of conversion (increase in the induration diameter of > or =10 mm to at least 15 mm), which is likely to increase specificity but decrease sensitivity, conversion rates were 12.5 and 2.8 conversions per 100 person-years in nursing and polytechnic school students, respectively (rate difference, 9.7 conversions per 100 person-years; 95% CI, 4.5-14.8 conversions per 100 person-years). Nursing students reportedly nursed 20,868 inpatients with tuberculosis during 315 person-years of training.

CONCLUSIONS

Both groups had high TST conversion rates, but the extremely high rates among nursing students imply high occupational exposure to Mycobacterium tuberculosis. Intense exposure to inpatients with tuberculosis was reported during training. Better prevention, surveillance, and management of institutional M. tuberculosis transmission need to be supported as part of the international response to the severe human immunodeficiency virus infection epidemic and health care worker crisis in Africa.

Surprisingly high specificity of the PPD skin test for M. tuberculosis infection from recent exposure in The Gambia

Background

Options for intervention against Mycobacterium tuberculosis infection are limited by the diagnostic tools available. The Purified Protein Derivative (PPD) skin test is thought to be non-specific, especially in tropical settings. We compared the PPD skin test with an ELISPOT test in The Gambia.

Methodology/Principal Findings

Household contacts over six months of age of sputum smear positive TB cases and community controls were recruited. They underwent a PPD skin test and an ELISPOT test for the T cell response to PPD and ESAT-6/CFP10 antigens. Responsiveness to M. tuberculosis exposure was analysed according to sleeping proximity to an index case using logistic regression. 615 household contacts and 105 community controls were recruited. All three tests assessed increased significantly in positivity with increasing M. tuberculosis exposure, the PPD skin test most dramatically (OR 15.7; 95% CI 6.6–35.3). While the PPD skin test positivity continued to trend downwards in the community with increasing distance from a known case (61.9% to 14.3%), the PPD and ESAT-6/CFP-10 ELISPOT positivity did not. The PPD skin test was more in agreement with ESAT-6/CFP-10 ELISPOT (75%, p = 0.01) than the PPD ELISPOT (53%, p<0.0001). With increasing M. tuberculosis exposure, the proportion of ESAT-6/CFP-10 positive contacts who were PPD skin test positive increased (p<0.0001), and the proportion of ESAT-6/CFP-10 negative contacts that were PPD skin test negative decreased (p<0.0001); the converse did not occur.

Conclusions/Significance

The PPD skin test has surprisingly high specificity for M. tuberculosis infection from recent exposure in The Gambia. In this setting, anti-tuberculous prophylaxis in PPD skin test positive individuals should be revisited.

A statewide assessment of tuberculin skin testing of preschool children enrolled in medicaid managed care

OBJECTIVES

This study examined tuberculosis screening among preschool children enrolled in a statewide Medicaid managed care program.

METHODS

A random sample of 2,000 was selected from 19 to 35 month old children who were continuously enrolled in Rhode Island's Medicaid managed care program for 1 year. Sociodemographic data were obtained from computerized administrative databases. Medical record audits were performed to obtain the dates and results of tuberculosis tests.

RESULTS

Data from the medical record audits were available for 1,988 of the study children. For 1,215 of the study children (1,215/1,988 = 61%) a tuberculin skin test had been performed, but a reading was only documented for 736 children (60% of children who received a tuberculin skin test) and only one child tested positive (0.1%).

CONCLUSIONS

A majority of preschool children in this population in which the prevalence of risk factors for tuberculosis is likely to be relatively high did have a tuberculosis test performed. However, in many cases the tuberculin skin test was either not read or the results not documented. The low rate of positivity is consistent with current AAP guidelines for selective tuberculin skin testing.