Redox biomarkers in asymptomatic latent human tuberculosis: a comparison with active disease.

BACKGROUND: The latent TB infection (LTBI) is an asymptomatic infection caused by Mycobacterium tuberculosis (M.bt). Previous studies have shown a host-protective role for Heme oxygenase-1 (HO-1) during Mtb infection and an important involvement of Glutathione peroxidase-4 (Gpx4) in the necrotic pathology of the disease. Furthermore, increasing evidence suggested a crucial role for Glutathione in the granulomatous response to M. tb infection, with altered GSH levels associated to decreased host resistance. The aim of this study was to provide additional tools for discriminating the pathologic TB state and the asymptomatic infection. METHODS: We analyzed the gene expression of HO-1 and Gpx4 enzymes in blood of subjects with LTBI, active TB and healthy controls, and we also measured blood levels of the reduced (GSH) and oxidized (GSSG) forms of glutathione, together with the evaluation of GCL expression, the gene responsible for the GSH de novo synthesis. RESULTS: Our findings highlight a shift of glutathione homeostasis towards a more reducing conditions in LTBI, and a different modulation of GSH-dependent genes and HO-1 expression respect to active TB. CONCLUSION: This study can provide useful tools to understand the redox background that address the infection toward the asymptomatic or active disease.

Treatment Outcomes for Tuberculosis Infection and Disease Among Persons Deprived of Liberty, Uganda, 2020.

We report that unsuccessful treatment outcomes were 11.8% for tuberculosis (TB) disease and 21.8% for TB infection among persons deprived of liberty in Uganda Prisons Service facilities. Remedial efforts should include enhancing referral networks to ensure treatment continuity, strengthening data systems for complete outcome documentation, and prioritizing short-course treatment regimens.

Facilitators and barriers to latent tuberculosis infection treatment among primary healthcare workers in Malaysia: a qualitative study.

BACKGROUND: Healthcare workers (HCWs) have an increased risk of active and latent tuberculosis infection (LTBI) compared to the general population. Despite existing guidelines on the prevention and management of LTBI, little is known about why HCWs who tested positive for LTBI refuse treatment. This qualitative study sought to explore the facilitators and barriers to LBTI treatment uptake among primary HCWs in Malaysia. METHODS: This qualitative study used a phenomenological research design and was conducted from July 2019 to January 2021. A semi-structured topic guide was developed based on literature and the Common-Sense Model of Self-Regulation. We conducted one focus group discussion and 15 in-depth interviews with primary care HCWs. Interviewees were 7 physicians and 11 allied HCWs who tested positive for LTBI by Tuberculin Skin Test or Interferon Gamma Release Assay. Audio recordings were transcribed verbatim and thematic analysis was used to analyse the data. RESULTS: We found four factors that serve as barriers to HCWs' LTBI treatment uptake. Uncertainties about the need for LTBI treatment, alongside several other factors including the attitude of the treating physician towards treatment, time constraints during clinical consultations, and concerns about the treatment itself. On the other hand, facilitators for LTBI treatment uptake can be grouped into two themes: diagnostic modalities and improving knowledge of LTBI treatment. CONCLUSIONS: Improving HCWs' knowledge and informative clinical consultation on LTBI and its treatment benefit, aided with a definitive diagnostic test can facilitate treatment uptake. Additionally, there is a need to improve infection control measures at the workplace to protect HCWs. Utilizing behavioural insights can help modify risk perception among HCWs and promote treatment uptake.

Development and Validation of a Parsimonious Tuberculosis Gene Signature Using the digital NanoString nCounter Platform.

BACKGROUND: Blood-based biomarkers for diagnosing active tuberculosis (TB), monitoring treatment response, and predicting risk of progression to TB disease have been reported. However, validation of the biomarkers across multiple independent cohorts is scarce. A robust platform to validate TB biomarkers in different populations with clinical end points is essential to the development of a point-of-care clinical test. NanoString nCounter technology is an amplification-free digital detection platform that directly measures mRNA transcripts with high specificity. Here, we determined whether NanoString could serve as a platform for extensive validation of candidate TB biomarkers. METHODS: The NanoString platform was used for performance evaluation of existing TB gene signatures in a cohort in which signatures were previously evaluated on an RNA-seq dataset. A NanoString codeset that probes 107 genes comprising 12 TB signatures and 6 housekeeping genes (NS-TB107) was developed and applied to total RNA derived from whole blood samples of TB patients and individuals with latent TB infection (LTBI) from South India. The TBSignatureProfiler tool was used to score samples for each signature. An ensemble of machine learning algorithms was used to derive a parsimonious biomarker. RESULTS: Gene signatures present in NS-TB107 had statistically significant discriminative power for segregating TB from LTBI. Further analysis of the data yielded a NanoString 6-gene set (NANO6) that when tested on 10 published datasets was highly diagnostic for active TB. CONCLUSIONS: The NanoString nCounter system provides a robust platform for validating existing TB biomarkers and deriving a parsimonious gene signature with enhanced diagnostic performance.

Strategies to detect and manage latent tuberculosis infection among household contacts of pulmonary TB patients in high TB burden countries - a systematic review and meta-analysis.

OBJECTIVE: To summarise latent tuberculosis infection (LTBI) management strategies among household contacts of bacteriologically confirmed pulmonary tuberculosis (TB) patients in high-TB burden countries. METHODS: PubMed/MEDLINE (NCBI) and Scopus were searched (January 2006 to December 2021) for studies reporting primary data on LTBI management. Study selection, data management and data synthesis were protocol-driven (PROSPERO-CRD42021208715). Primary outcomes were the proportions of LTBI, initiating and completing tuberculosis preventive treatment (TPT). Reported factors influencing the LTBI care cascade were qualitatively synthesised. RESULTS: From 3694 unique records retrieved, 58 studies from 23 countries were included. Most identified contacts were screened (median 99%, interquartile range [IQR] 82%-100%; 46 studies). Random-effects meta-analysis yielded pooled proportions for: LTBI 41% (95% confidence interval [CI] 33%-49%; 21,566 tested contacts); TPT initiation 91% (95% CI 79%-97%; 129,573 eligible contacts, 34 studies); TPT completion 65% (95% CI 54%-74%; 108,679 TPT-initiated contacts, 28 studies). Heterogeneity was significant (I2 ≥ 95%-100%) and could not be explained in subgroup analyses. Median proportions (IQR) were: LTBI 44% (28%-59%); TPT initiation 86% (60%-100%); TPT completion 68% (44%-82%). Nine broad themes related to diagnostic testing, health system structure and functions, risk perception, documentation and adherence were considered likely to influence the LTBI care cascade. CONCLUSION: The proportions of household contacts screened, detected with LTBI and initiated on TPT, though variable was high, but the proportions completing TPT were lower indicating current strategies used for LTBI management in high TB burden countries are not sufficient.

Concordance Between Point-of-Care Urine Ethyl Glucuronide Alcohol Tests and Self-Reported Alcohol Use in Persons with HIV in Uganda.

Screening and assessing alcohol use accurately to maximize positive treatment outcomes remain problematic in regions with high rates of alcohol use and HIV and TB infections. In this study, we examined the concordance between self-reported measures of alcohol use and point-of-care (POC) urine ethyl glucuronide (uEtG) test results among persons with HIV (PWH) in Uganda who reported drinking in the prior 3 months. For analyses, we used the screening data of a trial designed to examine the use of incentives to reduce alcohol consumption and increase medication adherence to examine the concordance between POC uEtG (300 ng/mL cutoff) and six measures of self-reported alcohol use. Of the 2136 participants who completed the alcohol screening, 1080 (50.6%) tested positive in the POC uEtG test, and 1756 (82.2%) self-reported using alcohol during the prior 72 h. Seventy-two percent of those who reported drinking during the prior 24 h had a uEtG positive test, with lower proportions testing uEtG positive when drinking occurred 24-48 h (64.7%) or 48-72 h (28.6%) prior to sample collection. In multivariate models, recency of drinking, number of drinks at last alcohol use, and Alcohol Use Disorders Identification Test - Consumption (AUDIT-C) score were associated with uEtG positivity. The highest area under the curve (AUC) for a uEtG positive test was for recency of drinking. Overall, we concluded that several measures of drinking were associated with POC uEtG positivity, with recency of drinking, particularly drinking within the past 24 h, being the strongest predictor of uEtG positivity.

QuantiFERON-TB Gold plus testing for the detection of LTBI among health care workers in major TB hospitals of the Northern Kyrgyz Republic.

BACKGROUND: Health care workers (HCW) are at increased risk of TB infection due to their close contact with infected patients with active TB. The objectives of the study were (1) to assess the prevalence of LTBI among HCW in the Northern Kyrgyz Republic, and (2) to determine the association of LTBI with job positions or departments. METHODS: HCWs from four TB hospitals in the Northern Kyrgyz Republic were tested with the interferon-gamma release assay (IGRA) Quantiferon-TB Gold plus (QFT) for the detection of an immune response to TB as marker of TB infection. Age was controlled for as a confounder. Univariate and multivariable analysis were performed using logistic regression to assess the association of the risk factors (job position, and department) with having a QTF positive result. Firth's penalized-likelihood estimates were used to account for the small-sample size. Pairwise comparisons using the Bonferroni correction (conservative) and comparisons without adjusting for multiple comparisons (unadjusted) were used to identify the categories where differences occurred. RESULTS: QFT yielded valid results for 404 HCW, with 189 (46.7%) having a positive test. In the National Tuberculosis Center there was an increased odds to have a positive QFT test for the position of physician (OR = 8.7, 95%, CI = 1.2-60.5, p = 0.03) and laboratory staff (OR = 19.8, 95% CI = 2.9-135.4, p < 0.01) when administration staff was used as the baseline. When comparing departments for all hospitals combined, laboratories (OR 7.65; 95%CI 2.3-24.9; p < 0.001), smear negative TB (OR 5.90; 95%CI 1.6-21.8; p = 0.008), surgery (OR 3.79; 95%CI 1.3-11.4; p = 0.018), and outpatient clinics (OR 3.80; 95%CI 1.1-13.0; p = 0.03) had higher odds of a positive QFT result than the admin department. Fifteen of the 49 HCW with follow-up tests converted from negative to positive at follow-up testing. CONCLUSIONS: This is the first report on prevalence and risk factors of LTBI for HCW in the Kyrgyz republic, and results indicate there may be an increased risk for LTBI among physicians and laboratory personnel. Further research should investigate gaps of infection control measures particularly for physicians and laboratory staff and lead to further improvement of policies.

Costimulatory CD226 Signaling Regulates Proliferation of Memory-like NK Cells in Healthy Individuals with Latent Mycobacterium tuberculosis Infection.

It is now widely accepted that NK cells can acquire memory, and this makes them more effective to protect against some pathogens. Prior reports indicate memory-like NK cells (mlNKs) in murine model of Mycobacterium tuberculosis (Mtb) as well as in healthy individuals with latent TB infection (LTBI). The increased expression of CD226 was evident in mlNKs from LTBI+ people after stimulation with γ-irradiated Mtb (γ-Mtb). We thus evaluated the contribution of costimulatory CD226 signaling in the functionality of mlNKs in LTBI+ people. We found that blockade of CD226 signaling using the antibody- or CRISPR/Cas9-mediated deletion of the CD226 gene in NK cells diminished the proliferation of mlNKs from LTBI+ people. Blocking CD226 signaling also reduced the phosphorylation of FOXO1 and cMyc expression. Additionally, cMyc inhibition using a chemical inhibitor reduced proliferation by mlNKs from LTBI+ people. Moreover, blocking CD226 signaling reduced glycolysis in NK cells, and the inhibition of glycolysis led to reduced effector function of mlNKs from LTBI+ people. Overall, our results provide a role for CD226 signaling in mlNK responses to Mtb.

Higher Levels of Alcohol Use Are Associated With Latent Tuberculosis Infection in Adults Living With Human Immunodeficiency Virus.

We assessed associations between hazardous alcohol use and latent tuberculosis infection (LTBI) among adults living with human immunodeficiency virus (HIV) in Uganda. We compared tuberculin skin test positivity across medium, high, and very-high alcohol use levels, classified by AUDIT-C scores. In multivariable analysis, very high use was associated with LTBI (adjusted odds ratio 1.61, 95% confidence interval: 1.03-2.50).

Prevalence and risk factors associated with latent tuberculosis infection among household contacts of smear positive pulmonary tuberculosis patients in South India.

OBJECTIVE: We aimed to determine the prevalence and find the risk factors associated with latent tuberculosis infection (LTBI) among the household contacts (HHC) of pulmonary TB patients. METHODS: This cohort study was conducted from 2014 to 2019. Pretested standardised questionnaires and tools were used for data collection. The prevalence of LTBI among HHCs of TB patients was summarised as proportion with 95% confidence interval (CI). Mixed-effects generalised linear modelling function (meglm) in STATA with family Poisson and log link was performed to find the factors associated with LTBI. RESULTS: In total, 1523 HHC of pulmonary TB patients were included in the study. Almost all HHC shared their residence with the index case (IC) for more than a year; 25% shared the same bed with the IC. The prevalence of LTBI among the HHC of TB patients was 52.6% (95% CI: 50.1-55.1%). In an adjusted model, we found that among HHC belonging to the age group of 19-64 years (aIRR = 1.2; 95% CI: 1.1-1.3; p-value: 0.02), to the age group >65 years (aIRR = 1.4, 95% CI: 1.1-1.9, p-value: 0.02) and sharing the same bed with the IC (aIRR = 1.2, 95% CI: 1.1-1.3, p value: 0.04) were independent determinants of LTBI among the HHC. CONCLUSION: One in two household contacts of TB patients have latent tuberculosis infection. This underscores the need of targeted contact screening strategies, effective contact tracing and testing using standardised methods in high TB burden settings.

Tuberculosis prevention in patients undergoing kidney transplantation: A nurse-led program for screening and treatment.

BACKGROUND: Systematic screening for, and treatment of, latent tuberculosis (TB) infection is recommended prior to kidney transplant. However, little is known about patient compliance with, or the safety profile of, preventive therapies used in clinical practice. METHODS: This was a retrospective observational study of patients who were eligible for kidney transplant and were evaluated for TB infection between January 2013 and June 2019 at the TB clinic of a tertiary care teaching hospital. All patient data were registered prospectively as part of our nurse-led program before kidney transplant. We assessed completion rates, tolerance with therapy, development of TB, and associated workload. RESULTS: In total, 1568 patients were referred to our TB clinic for evaluation. Preventive therapy was given to 385 patients and completed by 340 (88.3%). Of these, 89 (23.1%) experienced some intolerance, with 27 requiring full discontinuation. After a median follow-up of 45 months (1426 patient-years), 206 (53.5%) of the treated patients received a kidney transplant; only one patient, who failed to complete treatment, developed post-transplant TB (7.01 cases per 10 000 patient-years; 95% confidence interval, 0.35-34.59). Extra nurse or medical visits were required by 268 (69.6%) patients. CONCLUSION: Despite the complexity and workload generated by patients with ESRD awaiting kidney transplant, preventive therapy for TB is effective in most cases. Our experience provides important evidence on the feasibility of preventive therapy for TB before kidney transplant when delivered as part of a comprehensive nurse-led program.

Comparison of QuantiFERON-TB Gold Plus, QuantiFERON-TB Gold In-Tube, and T-SPOT.TB among patients with tuberculosis.

OBJECTIVES: This study evaluated the efficacy of the following interferon (IFN)-γ release assays (IGRAs): QuantiFERON-TB Gold Plus (QFT-Plus), QFT-Gold In-Tube (QFT-GIT), and T-SPOT. TB (T-SPOT) with the quantitative values of IFN-γ response. METHODS: Blood samples were collected from patients with active tuberculosis (TB), latent TB infection (LTBI), individuals with previous TB infection, and healthy volunteers enrolled between May 2017 and June 2018. RESULTS: IGRAs results were analyzed in 175 subjects (76 had active TB, 14 had LTBI, 35 had prior TB infection, and 50 were healthy). QFT-Plus and QFT-GIT revealed equal efficacy for IFN-γ values, and the IFN-γ response in QFTs tended to increase with the spot counts in T-SPOT, with similar high sensitivities (approximately 90%) in the active TB group. The test concordance of two of three IGRAs was optimal among all subjects (κ coefficients: 0.82-0.96). Additionally, the median quantitative values of IFN-γ with QFT-Plus and QFT-GIT were higher in the active TB group than in the LTBI and previous TB groups. CONCLUSION: Three IGRAs showed equivalent efficacy with high sensitivities and higher IFN-γ response in active TB group than that in non-active TB group.

The effect of smoking on latent tuberculosis infection susceptibility in high risk individuals in Iran.

Tuberculosis has been declared as a global emergency. Latent tuberculosis infection (LTBI) is a state in which host immunity cannot completely eradicate Mycobacterium tuberculosis. Cigarette smoke increases the risk of respiratory infections, such a TB, as it has adverse effects on respiratory immune function. In this cross-sectional study, which was performed from 2016 to 2017, 31 patients with newly diagnosed lung cancer, 63 Chronic obstructive pulmonary disease (COPD), 46 with problems in respiratory system, and 40 healthy subjects were studied. Demographic data of all subjects were recorded via a questionnaire. IGRAs (Interferon-γ release assays) were used to determine LTBI. We showed that smoking has significant odds ratio for COPD patients (OR: 4.58, 95% CI: 1.93-10.87). Also, the concordance of smoking with COPD (OR: 22, 95% CI: 2.7-179.2), lung cancer (OR: 10, 95% CI: 1.03-97), and other respiratory diseases (OR: 4.54, 95% CI: 1.93-10.87) is a significant risk factor for the presence of LTBI whereas the existence of LTBI in the study groups did not show any significant odds ratio. This study is the first to analyze the relationship between smoking in patients with respiratory diseases and LTBI susceptibility in Iran by IGRAs, which proposes cigarette smoking as a powerful risk factor for LTBI.

MicroRNA-23a-3p Down-Regulation in Active Pulmonary Tuberculosis Patients with High Bacterial Burden Inhibits Mononuclear Cell Function and Phagocytosis through TLR4/TNF-α/TGF-ß1/IL-10 Signaling via Targeting IRF1/SP1.

The aim of this study is to explore the role of microRNAs (miR)-21/23a/146a/150/155 targeting the toll-like receptor pathway in active tuberculosis (TB) disease and latent TB infection (LTBI). Gene expression levels of the five miRs and predicted target genes were assessed in peripheral blood mononuclear cells from 46 patients with active pulmonary TB, 15 subjects with LTBI, and 17 non-infected healthy subjects (NIHS). THP-1 cell lines were transfected with miR-23a-3p mimics under stimuli with Mycobacterium TB-specific antigens. Both miR-155-5p and miR-150-5p gene expressions were decreased in the active TB group versus the NIHS group. Both miR-23a-3p and miR-146a-5p gene expressions were decreased in active TB patients with high bacterial burden versus those with low bacterial burden or control group (LTBI + NIHS). TLR2, TLR4, and interleukin (IL)10 gene expressions were all increased in active TB versus NIHS group. MiR-23a-3p mimic transfection reversed ESAT6-induced reduction of reactive oxygen species generation, and augmented ESAT6-induced late apoptosis and phagocytosis, in association with down-regulations of the predicted target genes, including tumor necrosis factor (TNF)-α, TLR4, TLR2, IL6, IL10, Notch1, IL6R, BCL2, TGF-ß1, SP1, and IRF1. In conclusion, the down-regulation of miR-23a-3p in active TB patients with high bacterial burden inhibited mononuclear cell function and phagocytosis through TLR4/TNF-α/TGF-ß1/IL-10 signaling via targeting IRF1/SP1.

Prevalence of latent tuberculosis infection in healthcare workers in tertiary care hospitals of Pakistan.

OBJECTIVE: To determine the prevalence of latent tuberculosis infection (LTBI) in healthcare workers in tertiary care hospitals of Rawalpindi, using interferon gamma release assay. METHODS: It was a cross-sectional study. The samples were collected from pulmonology and microbiology departments of three hospitals; i) Military Hospital, Rawalpindi, ii) Fauji Foundation Hospital, Rawalpindi and iii) Pakistan Institute of Medical Sciences, Islamabad. The study was completed in one year from January 2017 to January 2018. Fifty-five asymptomatic healthcare workers of both genders between the ages of 18-50 years with a working tenure of at least one year in concerned departments were included and those with active tuberculosis were excluded from the study. Whole blood from subjects was collected and plasma was checked for interferon gamma value by IGRA (Interferon gamma release assay). RESULTS: In this study of total 55 healthcare workers a high prevalence 22 (40.0%) of latent tuberculosis was found. When LTBI distribution was analyzed within occupational categories, the most frequently affected were sanitary workers 3 (100.0%), nurses 5 (50.0%), doctors 6 (43%) and nursing assistants 2 (40%). CONCLUSION: The prevalence of LTBI in healthcare workers is alarmingly high in our local healthcare settings.

Enhanced IFN-γ, but not IL-2, response to Mycobacterium tuberculosis antigens in HIV/latent TB co-infected patients on long-term HAART.

BACKGROUND: HIV-infected individuals with latent TB infection are at increased risk of developing active TB. HAART greatly reduces the incidence rate of TB in HIV-infected patients and reconstitutes Mycobacterium tuberculosis (M. tuberculosis)-specific immune response in the first 12 months of therapy. The durability of the anti-mycobacterial immune restoration after a year of HAART however remains less investigated. METHOD: A cross-sectional study was conducted to evaluate M. tuberculosis-specific functional immune responses in HIV/latent TB co-infected patients who were on HAART for at least 1.5 up to 9 years as compared to HAART-naïve patients. Three-hundred sixteen HIV-infected patients without active TB were screened by tuberculin skin testing for M. tuberculosis infection and peripheral blood mononuclear cells (PBMCs) were isolated from 61 HIV/latent TB co-infected patients (30 HAART-naïve and 31 HAART-treated). IFN-γ and IL-2 ELISPOT as well as CFSE cell proliferation assays were performed after stimulation with M. tuberculosis antigens PPD and ESAT-6. RESULT: The median frequency of PPD and ESAT-6 specific IFN-γ secreting cells was significantly higher in the HAART-treated patients as compared to HAART-naïve patients, p = 0.0021 and p = 0.0081 respectively. However, there was no significant difference in the median frequency of IL-2 secreting cells responding to PPD (p = 0.5981) and ESAT-6 (p = 0.3943) antigens between HAART-naïve and-treated groups. Both IFN-γ and IL-2 responses were independent of CD4+ T cell count regardless of the HAART status. Notably, the frequency of PPD and ESAT-6 specific IL-2 secreting cells was positively associated with CD4+ T cell proliferation while inversely correlated with duration of HAART, raising the possibility that M. tuberculosis-specific IL-2 response that promote the antigen-specific CD4+ T cell proliferation diminish with time on antiretroviral therapy in HIV/latent TB co-infected patients. CONCLUSION: This study shows an increased M. tuberculosis-specific IFN-γ, but not IL-2, response in HIV/latent TB co-infected patients with long-term HAART, consistent with only partial immune restoration. Future studies should, therefore, be done to prospectively define the rate and extent to which functional immune responses to M. tuberculosis are restored after long-term HAART.

Comparing QuantiFERON-TB Gold Plus with Other Tests To Diagnose Mycobacterium tuberculosis Infection.

The fourth-generation QuantiFERON test for tuberculosis infection, QuantiFERON-TB Gold Plus (QFT-Plus) has replaced the earlier version, QuantiFERON-TB Gold In-Tube (QFT-GIT). A clinical need exists for information about agreement between QFT-Plus and other tests. We conducted this study to assess agreement of test results for QFT-Plus with those of QuantiFERON-TB Gold In-Tube (QFT-GIT), T-SPOT.TB (T-SPOT), and the tuberculin skin test (TST). Persons at high risk of latent tuberculosis infection (LTBI) and/or progression to tuberculosis (TB) disease were enrolled at the 10 sites of the Tuberculosis Epidemiologic Studies Consortium from October 2016 through May 2017; each participant received all four tests. Cohen's kappa (κ) and Wilcoxon signed-rank test compared qualitative and quantitative results of QFT-Plus with the other tests. Test results for 506 participants showed 94% agreement between QFT-Plus and QFT-GIT, with 19% positive and 75% negative results. When the tests disagreed, it was most often in the direction of QFT-GIT negative/QFT-Plus positive. QFT-Plus had similar concordance as QFT-GIT with TST (77% and 77%, respectively) and T-SPOT (92% and 91%, respectively). The study showed high agreement between QFT-GIT and QFT-Plus in a direct comparison. Both tests had similar agreement with TST and T-SPOT.

Expected background rates of latent TB infection in London inner city schools: lessons from a TB contact investigation exercise in a secondary school.

Following an extensive contact tracing exercise at a school in a London borough with one of highest tuberculosis (TB) rates in England, we estimated the background prevalence of latent TB infection to be significantly less than the widely accepted 10%. We screened 271 pupils aged 14-15 years in two groups: 96 pupils in group 1 had significant exposure (>8 h/week in the same room) to a case of infectious TB and 175 in group 2 who had minimal exposure. In group 1, 26% were diagnosed with latent or active TB, compared to 6.3% in group 2. Risk factors for TB infection (e.g. previous exposure or link to high-prevalence communities) were analysed using a cohort study design. In the univariable analysis only being in contact group 1 was statistically significantly associated with being a case (OR 5.25, 95%, P < 0.001). In the multivariable model contact group 1 remained significantly associated with being a case (adjusted OR 4.40, P = 0.001). We concluded that the 6.3% yield of TB infection in contact group 2 is either similar to or higher than the background prevalence rate of latent TB infection (LTBI) in this high TB prevalence London borough. Other parts of England with lower TB prevalence are likely to have even lower LTBI rates.

Acceptability of latent tuberculosis testing of migrants in a college environment in England.

OBJECTIVES: The majority of tuberculosis (TB) cases in England occur from reactivation of latent tuberculosis infection (LTBI) in the settled migrant population. The National Institute for Health and Clinical Excellence recommends that new entrants from high-incidence countries are screened to detect LTBI. This article seeks to describe an outreach programme and testing for LTBI in an innovative setting-ESOL (English for Speakers of Other Languages) classes at a community college (CC) with evaluation of acceptability. STUDY DESIGN: Partnership working with mixed methods used for evaluation of acceptability. METHODS: A pre-existing network from the local TB partnership designed an outreach intervention and screening for LTBI among students from an ESOL programme at a CC. Screening for LTBI with interferon gamma release assay was the culmination of a programme of health improvement activities across the college. Any student on the ESOL programme younger than the age of 35 years and resident in the UK for less than 5 years was eligible for testing. LTBI testing was carried out on-site, and the experience was evaluated by questionnaires to staff, students and partners. A facilitated debrief among the partners gave further data. RESULTS: A total of 440 eligible students were tested. One hundred and seventy-two student feedback questionnaires were completed, and 36 partner questionnaires were received with 18 CC staff responding. Students, tutors and healthcare professionals found the setting acceptable with some concerns about insufficient resource for timely follow-up. CONCLUSIONS: Students, tutors, community organisations and health professionals found the exercise worthwhile and the method and setting acceptable. There were resource issues for the clinical team in follow-up of students with positive results for such a large screening event. Unexpected barriers were found by the CC as this kind of activity was not recognised for external quality review purposes. There were concerns about reputational loss and stigma of being involved in a TB project. As current initiatives aim to divert workload from stretched general practice surgeries, this may be an important addition to primary care screening.

Vitamin D Levels in Active TB, Latent TB, Non-TB Pneumonia and Healthy Children: A Prospective Observational Study.

BACKGROUND: Growing evidence suggests that vitamin D deficiency might be implicated in the development of active tuberculosis (TB). We evaluated vitamin D levels in children with active TB compared to children with latent TB infection (LTBI), non-TB pneumonia (NTBP) and healthy controls to determine if there was a difference. METHODS: In this prospective study, vitamin D levels were measured and compared between the four groups and adjusted for age, ethnicity, gender and season of sample collection. RESULTS: Fifty-seven children were included: 24.6% active TB, 28.1% LTBI, 22.8% NPTB and 24.6% healthy controls. 36.8% of all children tested had an insufficient or deficient vitamin D level. Vitamin D level was significantly lower in active TB compared to other groups (p = 0.004). CONCLUSIONS: Our study showed a correlation between hypovitaminosis D and active pulmonary TB.