Positive Tuberculin Skin Test Results Research Articles

Patient perceptions of a tuberculosis testing program provided in the community pharmacy setting

ObjectivesThis study sought to describe patient experiences and perceptions of a public health initiative designed to improve tuberculosis (TB) testing access using the tuberculin skin test (TST) in a community pharmacy setting. Study designThis was a cross-sectional study. MethodsA telephonic survey of patients who had received a TST at one of twelve participating community pharmacies between August 2014 and July 2016 was conducted. The 26-question survey was developed by two pharmacists with expertise in TB management and one pharmacy student. Before administration the survey was peer-reviewed for clarity. Potential study patients were identified through TST records at the study pharmacies. English-speaking patients older than 18 years were eligible for study inclusion. Statistical differences in responses based on location were identified using chi-squared test for frequency comparisons with a P-value of <0.05 to determine statistical significance. ResultsA total of 1709 patients received a TST during the study period, of whom 431 were contacted and 325 participated, meeting the predetermined representative sample needed of 314 patients. The majority of study patients were female (67.1%) and white (81%). The mean age was 36 years (standard deviation = 14.1). A majority (68.3%) lived <5 miles from the TST pharmacy, while 45.2% of those with a primary care provider (PCP) (61.6% of respondents) lived within 5 miles of the PCP's office. Care was accessible and met patients' testing needs. For most patients (84.6%), the initial and follow-up appointments took < 20 min. Follow-up TST reading rate was 98.5%; 4.3% of tests were positive. Positive TST results were associated with use of a small city pharmacy (P = 0.003). Perception differences based on location were identified. ConclusionsUptake of the TST service in the community pharmacy setting was high and patients reported positive experiences.

The use of GeneXpert Mycobacterium tuberculosis/rifampicin assay in diagnosis of pulmonary tuberculosis in children

Introduction Rapid diagno sis of tuberculosis (TB) is essential for early disease management. GeneXpert (GX) test is a novel rapid diagnostic modality. In this study, we aimed to evaluate the diagnostic role of GX test in diagnosing pulmonary tuberculosis (PTB) in children as well as detection of rifampicin (RIF) resistance. Patients and methods This was a cross-sectional study that included 80 patients suspected to have PTB based on clinical data together with at least one of the followings: a positive tuberculin skin test or QuantiFERON-TB Gold In-Tube test result, a positive blood TB PCR result, or a positive Ziehl–Neelsen staining result. Results PTB was more common in older females. Extrapulmonary manifestations and hilar lymphadenopathy were more frequent in younger age. Both positive tuberculin skin test and positive GX were more frequent in older age. Positive GX was found in 30 (37.5%) cases, and RIF resistance was detected in two (6.6%) of them. Positive GX results were more frequent in sputum than gastric aspirate samples. Positive GX results were more frequent with absent Bacillus Calmette–Guerin scar, and with hemoptysis, failure to thrive, cavitary lung lesions, and lower mean hemoglobin. Conclusion GX detects many more cases than blood PCR and Ziehl–Neelsen stain. GX had 70% sensitivity and 95% specificity in diagnosing PTB, with overall diagnostic accuracy of 86.67%, with better performance in older children who could expectorate. RIF resistance was ∼6.6%.

Latent Tuberculosis Infection among Healthcare Students and Postgraduates in a Mediterranean Italian Area: What Correlation with Work Exposure?

Background: Tuberculosis screening is part of the standard protocol for evaluating the risk of infection in healthcare workers. The aim of this study was to evaluate the prevalence of latent tuberculosis infection (LTBI) among students attending various healthcare profession degree courses and postgraduate medical courses at the School of Medicine of the University of Palermo, Italy, and assess the possible professional origin of infection. Methods: In total, 2946 students (2082 undergraduates and 864 postgraduates) took part in a screening program for LTBI between January 2014 to April 2019 using the tuberculin skin test (TST). Students with a positive TST result underwent a Quantiferon-TB test (QFT). Results: Among the 2082 undergraduates, 23 (1.1%) had a positive TST; the result was confirmed with QFT for 13 (0.62%) of them. Among the 864 postgraduate students, 24 (2.78%) had a positive TST and only 18 (2.08%) showed a positive QTF. Latent tuberculosis infections were significantly more frequent among postgraduates than undergraduates (2.08% > 0.62%, p < 0.0001). There was a higher number of subjects previously vaccinated for TB (18.87% > 0.24%, p < 0.0001), and of vaccinated subjects found positive for TST and QTF (66.67% > 7.69%, p = 0.001) in the postgraduate group. Conclusion: Latent TB is relatively low among medical school students in our geographic area. Nevertheless, this infectious disease must be regarded as a re-emerging biohazard for which preventive strategies are required to limit the risk of infection, especially among exposed workers.

Factors associated with tuberculosis disease among children who are household contacts of tuberculosis cases in an urban setting in Malaysia

BackgroundWith the rise in prevalence of childhood tuberculosis (TB) globally, contact tracing should be a powerful strategy for early diagnosis and management, especially in children who are household contacts of active TB cases. Here, we aimed to determine the prevalence and factors associated with TB disease in children who are household contacts of TB cases.MethodsWe used a cross-sectional study with data from the Malaysian TB Information System (TBIS) recorded from 1 January 2014 to 31 December 2017. All children aged 0–14 years who were registered in the TBIS with at least one household contact of TB cases were included in the study. Multiple logistic regression analysis was performed to calculate the adjusted odds ratio (adj. OR) and for adjusting the confounding factors.ResultsA total of 2793 children were included in the study. The prevalence of active TB was 1.5% (95% confidence interval [CI]: 1.31, 1.77%). Children aged < 5 years [adj. OR 9.48 (95% CI: 3.41, 26.36) p < 0.001] with positive tuberculin skin test [adj. OR 395.73 (95% CI: 134.17, 1167.13), p < 0.001] and investigation period of > 6 weeks [adj. OR 7.48 (95% CI: 2.88, 19.43), p < 0.001] had significantly higher odds for TB disease.ConclusionsThe prevalence of TB disease in children who were household contacts of TB cases is relatively low. However, contact tracing programmes should not only focus on children aged < 5 years and with positive tuberculin skin test results, but also be empowered to reduce the investigation period.

Radiological Signs of Latent Tuberculosis on Chest Radiography: A Systematic Review and Meta-Analysis.

ObjectiveCurrent guidelines recommend screening for latent tuberculosis infection (LTBI) with a tuberculin skin test (TST) or interferon gamma release assay (IGRA), or both. Many also recommend chest radiography (CXR), although its added value is uncertain. This systematic review assessed the prevalence of abnormalities suggestive of LTBI on CXR (LTBI-CXR lesions) and evaluated the strength of the association.MethodWe searched 4 databases up to September 2017 and systematically reviewed cross-sectional and cohort studies reporting LTBI-CXR lesions in individuals with a positive TST or IGRA, or both, result. Prevalence estimates were pooled using random effects models and odds ratios (ORs) were used to calculate risk estimates.ResultsIn the 26 included studies, the pooled proportion of individuals with LTBI having LTBI-CXR lesions was 0.15 (95% confidence interval [CI], 0.12–0.18]. In 16 studies that reported on individuals with LTBI and uninfected controls, LTBI-CXR lesions were associated with a positive TST result ≥ 5 mm or ≥ 10 mm (OR, 2.45; 95% CI, 1.00–5.99; and OR, 2.06; 95% CI, 1.38–3.09, respectively) and with a positive QuantiFERON result (OR, 1.99; 95% CI, 1.17–3.39) compared to CXR in uninfected controls. Although few studies reported specified lesions, calcified nodules were most frequently reported in individuals with LTBI (proportion, 0.07; 95% CI, 0.02–0.11).ConclusionsLesions on CXR suggestive of previous infection with Mycobacterium tuberculosis were significantly associated with positive tests for LTBI, although the sensitivity was only 15%. This finding may have added value when detection of past LTBI is important but immunodiagnostic tests may be unreliable.

Evaluating a 24-year tuberculosis screening in first-grade elementary schoolers in a low-burden area.

Early diagnosis of tuberculosis infection can significantly contribute to the control of the disease. The aim of the present study was to describe the tuberculin skin test (TST) trends over a 24-year period (1990-2013) and explore the value of universal tuberculosis screening in a low-burden area. All first graders that underwent TST during the 24-year study period (1990-2013) on the island of Crete, Greece, were retrospectively included in the study. A total of 82402 children (92.3% of Greek nationality; 51.0% male) underwent TST, of whom 335 (0.41%, 95% CI 0.37-0.46) were found to have positive TST while 0.27% of the study population had a TST between 5 and 9mm. The tuberculin index declined significantly between 1990-1994 and 2010-2013 (0.67 vs 0.26; RR 2.73, 95% CI 1.82-4.09; p<0.0001). Positive TST result was significantly higher in the immigrant than the native group (0.66% vs 0.24%; RR 3.76 95%, CI 2.89-4.84; p<0.0001). In the last study years, 386 children (488 native; 153 immigrant) should be tested for one to be found TST positive. Our findings question the massive tuberculin testing in low-burden areas and point to selective screening of high-risk groups.

Good Agreement between an Interferon Gamma Release Assay and Tuberculin Skin Tests in Testing for Latent Tuberculosis Infection among HIV-Infected Patients in Indonesia.

BackgroundLatent tuberculosis infection is a condition where there is a persistent immune response to Mycobacterium tuberculosis without clinical manifestations of tuberculosis. Currently, there is no gold standard to diagnose latent tuberculosis infection. The tuberculin skin test and interferon-gamma release assay are currently used to diagnose latent tuberculosis infection. However, studies have shown inconsistencies regarding the level of agreement between these tests in different settings. In this study, we aimed to evaluate the agreement between these two tests for diagnosing latent tuberculosis infection in human immunodeficiency virus (HIV)-infected individuals.MethodsWe screened HIV patients with no clinical symptoms of tuberculosis, a normal chest X-ray, and no history of tuberculosis or use of antituberculous drugs. Participants were tested with tuberculin skin test (TST) and T-SPOT.TB (an interferon gamma release assay) simultaneously. Participants' HIV stage was determined by measuring the level of CD4+ T-lymphocytes. Tuberculosis status was confirmed by sputum examination using GeneXpert. The level of agreement between the TST and T-SPOT.TB results was measured using Cohen's κ coefficient.ResultsOf the 112 participants, 20 had a positive T-SPOT.TB test result, and 21 had a positive TST result. The TST and T-SPOT.TB test results showed a high level of agreement (κ = 0.648, P < 0.001). Performance of the tests did not vary with CD4+ level. However, in participants with CD4+ < 200 cells/mm3, T-SPOT.TB detected more latent tuberculosis infections than the TST.ConclusionThere was good agreement between the TST and T-SPOT.TB results of latent tuberculosis infection in participants. TST is the preferred test for diagnosing latent tuberculosis infection in HIV-infected patients, especially in resource-limited settings, because it is simple and cost-effective. However, T-SPOT.TB may be useful to rule out latent tuberculosis infection in patients with severe immunodeficiency.

Screening for latent tuberculosis infection prior to biologic therapy in patients with chronic immune-mediated inflammatory diseases (IMID): Interferon-gamma release assay (IGRA) versus tuberculin skin test (TST)

BackgroundThe screening for latent tuberculosis infection (LTBI) is mandatory before initiating biologics in patients with chronic immune-mediated inflammatory disease (IMID). The recommendations are based on the tuberculin skin test (TST) and interferon-gamma release assay (IGRA). Aim of the workTo evaluate the agreement between the two tests in the diagnosis of LTBI and to identify risk factors associated with positive TST and IGRA results. Patients and methodsMedical records of 105 IMID patients going to receive a biologic agents were extracted in a cross sectional study (2015–2017). No biologics was undertaken before LTBI screening. All patients underwent IGRA and chest radiography. TST was performed in 94 cases. ResultsThe mean age of the patients was 47.7 ± 14.4 years and disease duration of 11.2 ± 7.6 years. Agreement between the 2 tests results was low (κ coefficient = 0.08). The sensitivity of TST and IGRA was equally low but the specificity of IGRA was higher. Replacing TST results by positive IGRA showed that number of patients who would take anti-tuberculous chemoprophylaxis will be significantly reduced by 46.5% (from 40.9% to 21.9%; p = 0.0002). TST results were significantly less positive for patients receiving immunosuppressives than for those receiving no treatment (35.1% vs 42.5%, p = 0.031). IGRA results were associated with absence of Bacilli Calemtte-Guérin vaccination. Age was the only risk factor for LTBI associated with both IGRA and TST positivity (p = 0.031, p = 0.011 respectively). ConclusionsTST and IGRA have a low agreement. Both tests should be included in the strategy to diagnose LTBI prior to biologic therapy in IMID patients.

Results of a population screening intervention for tuberculosis in a Nunavik village, Quebec, 2015-2016.

A small village in Nunavik, Quebec experienced a tuberculosis (TB) outbreak in 2012-2013 and then a resurgence in 2015-2016. Cases were still occurring, despite the fact that contact tracing had already been conducted on one quarter of the population. A decision was taken to conduct large-scale screening of the population for TB. To describe the results of a population-based TB screening intervention designed to identify individuals with latent TB infection (LTBI) or active TB requiring treatment. The history of TB infection (either active TB or LTBI, defined as a positive tuberculin skin test result of at least five mm induration) and treatment (considered adequate if at least 80% of prescribed doses were taken) were determined. Those who were two years of age and older and had not been included in contact tracing after June 1, 2015 were included for TB screening (n=1,026 eligible individuals). Screening included a nurse assessment, tuberculin skin test (TST) for those with previous negative TST or of unknown status and chest X-ray for the others. Of the eligible individuals in the affected village, 1,004 (98%) participated in the screening. Of these, 30% had a history of previous TB infection. A TST screening was administered to 71% of the participants, 10% of whom had positive results. Assessments were performed on 425 participants and 385 underwent a chest X-ray. Fifty-two cases of previously diagnosed active TB and three cases of new active TB were documented. In addition, there were 247 individuals with LTBI who had been previously identified (191 were found to have had adequate LTBI treatment, 56 were found to have had inadequate LTBI treatment) and 69 were identified with de novo LTBI. In addition, 633 participants were found to have no TB infection. There were 125 participants who were referred for LTBI treatment. Follow-up information was available for 120 and 85 (71%) of these completed the treatment. Within this northern village, which had persistent TB transmission despite classic control measures, population-based screening had a high degree of coverage and was an effective way to detect additional cases of individuals with active TB and those with LTBI.

Risk of latent tuberculosis infection among diabetic patients in Azadi Teaching Hospital, Duhok province: a case control study

Diabetes can be linked with impaired host immunity that subsequently increases the rate of various infections including tuberculosis (TB), particularly in developing countries where TB is endemic. The objectives of this case control study were to determine the prevalence and the risk of LTBI among diabetic patients. It is a prospective case control study conducted in Azadi Teaching Hospital from September 2017 until May 2018. The diabetic patients included in this study were randomly selected. The diagnosis of diabetes mellitus (DM) was made according to the American Diabetes Association (ADA). Diabetes mellitus patients and the control participants were offered a voluntary tuberculin skin test (TST). The TST ≥10 mm was considered positive. The results were analyzed by entering the data in SPSS (statistical package for the social sciences, version 16; SPSS Inc., Chicago, Illinois, USA). Two hundred DM patients and 208 control individuals participated in this study. Collectively, 28 patients had positive TST results. Based on the sputum smear microscopy and CXR, none of these patients showed active TB disease. The differences between the DM patients and the control group had no statistical significance apart from previous hospitalization. The prevalence of LTBI was 23.53% in the diabetic group, whereas, it was 9.62% in the control group. The frequency of LTBI in diabetic patients was significantly higher than the control group. When the diabetic group was compared with the control group in terms of diabetic control and the duration of diabetes disease, there was a statistically significant association of diabetes duration ≥ 10 years and TST positivity. In conclusion, the previous hospitalization was a significant risk factor for diabetic patients to acquire TB bacilli. Latent TB infection was more common in diabetics than non diabetics and there was an increased likelihood of having LTBI with the duration of diabetes ≥ 10 years. To avoid the threatening of TB control program, prophylactic treatment of LTBI in diabetic patients is paramount.Asian J. Med. Biol. Res. June 2018, 4(2): 227-232

Prognostic value of interferon-γ release assays and tuberculin skin test in predicting the development of active tuberculosis (UK PREDICT TB): a prospective cohort study

SummaryBackgroundTackling tuberculosis requires testing and treatment of latent tuberculosis in high-risk groups. The aim of this study was to estimate the predictive values of the tuberculin skin test (TST) and two interferon-γ release assays (IGRAs) for the development of active tuberculosis in high-risk groups—ie, people in recent contact with active tuberculosis cases and from high-burden countries.MethodIn this prospective cohort study, we recruited participants from 54 centres (eg, clinics, community settings) in London, Birmingham, and Leicester in the UK. Participants were eligible if they were aged 16 years or older and at high risk for latent tuberculosis infection (ie, recent contact with someone with active tuberculosis [contacts] or a migrant who had arrived in the UK in the past 5 years from—or who frequently travelled to—a country with a high burden of tuberculosis [migrants]). Exclusion criteria included prevalent cases of tuberculosis, and participants who were treated for latent tuberculosis after a positive test result in this study. Each participant received three tests (QuantiFERON-TB Gold-In Tube, T-SPOT.TB, and a Mantoux TST). A positive TST result was reported using three thresholds: 5 mm (TST-5), 10 mm (TST-10), and greater than 5 mm in BCG-naive or 15 mm in BCG-vaccinated (TST-15) participants. Participants were followed up from recruitment to development of tuberculosis or censoring. Incident tuberculosis cases were identified by national tuberculosis databases, telephone interview, and review of medical notes. Our primary objective was to estimate the prognostic value of IGRAs compared with TST, assessed by the ratio of incidence rate ratios and predictive values for tuberculosis development. The study was registered with ClinicalTrials.gov, NCT01162265, and is now complete.FindingsBetween May 4, 2010, and June 1, 2015, 10 045 people were recruited, of whom 9610 were eligible for inclusion. Of this cohort, 4861 (50·6%) were contacts and 4749 (49·4%) were migrants. Participants were followed up for a median of 2·9 years (range 21 days to 5·9 years). 97 (1·0%) of 9610 participants developed active tuberculosis (77 [1·2%] of 6380 with results for all three tests). In all tests, annual incidence of tuberculosis was very low in those who tested negatively (ranging from 1·2 per 1000 person-years, 95% CI 0·6–2·0 for TST-5 to 1·9 per 1000 person-years, 95% CI 1·3–2·7, for QuantiFERON-TB Gold In-Tube). Annual incidence in participants who tested positively were highest for T-SPOT.TB (13·2 per 1000 person-years, 95% CI 9·9–17·4), TST-15 (11·1 per 1000 person-years, 8·3–14·6), and QuantiFERON-TB Gold In-Tube (10·1 per 1000 person-years, 7·4–13·4). Positive results for these tests were significantly better predictors of progression than TST-10 and TST-5 (eg, ratio of test positivity rates in those progressing to tuberculosis compared with those not progressing T-SPOT.TB vs TST-5: 1·99, 95% CI 1·68–2·34; p<0·0001). However, TST-5 identified a higher proportion of participants who progressed to active tuberculosis (64 [83%] of 77 tested) than all other tests and TST thresholds (≤75%).InterpretationIGRA-based or BCG-stratified TST strategies appear most suited to screening for potential disease progression among high-risk groups. Further work will be needed to assess country-specific cost-effectiveness of each screening test, and in the absence of highly specific diagnostic tests, cheap non-toxic treatments need to be developed that could be given to larger groups of people at potential risk.FundingNational Institute for Health Research Health Technology Assessment Programme 08-68-01.

Knowledge, experiences, and attitudes toward Mantoux test among medical and health professional students in Italy: a cross-sectional study.

The World Health Organization's Action Framework for tuberculosis elimination in low-tuberculosis incidence countries includes the screening for active and latent tuberculosis in selected high-risk groups, including health care workers. In this context, medical and health profession students, exposed to nosocomial tuberculosis transmission during training and clinical rotations, are target populations for tuberculosis screening. No updated data are available on tuberculosis screening practice and knowledge of medical and health profession students in Italy. Within the activities Italian Study Group on Hospital Hygiene of the Italian Society of Hygiene, Preventive Medicine and Public Health, we carried out a multicentre cross-sectional study to assess knowledge, attitude and practices on tuberculosis prevention and control among Medical, Dentistry, Nursing and other health professions' students. Students were enrolled in the study on a voluntary basis and were administered a previously piloted structured questionnaire. Logistic regression models were applied to explore knowledge on tuberculosis prevention by selected socio-demographic variables and University-based tuberculosis prevention practice. Students of seventeen Universities across Italy participated in the study, and 58.2% of them received compulsory tuberculin skin test either at enrollment or while attending clinical practice. A total of 5,209 students filled the questionnaire. 37.7% were medicine and dentistry students (Group 1), 44.9% were nursing students (Group 2) and 17.4% were other health professions' students (Group 3). Age and gender had different distributions by groups, as well as knowledge and practice on tuberculin skin test. 84.4% of the study population (95% CI = 83.3-85.3) was aware of the existence of the tuberculin skin test, 74.4% (95% CI = 73.2-75.6) knew what is the first-level screening test for latent tuberculosis and only 22.5% (95% CI = 21.4-23.6) knew how to proceed after a positive tuberculin skin test result. Overall, knowledge on tuberculosis prevention was higher in Group 2 and lower Group 3, as compared to Group 1. In Italy, the knowledge on tuberculosis screening among University students is generally good. To reduce some of the criticalities found among the different study courses, it would be appropriate to harmonize both the regulations on tuberculosis screening practices for admission to University courses, and the educational activities on the topic of tuberculosis, to be extended to all workers involved in health care setting.

Prevalence of latent Mycobacterium tuberculosis infection in renal transplant recipients.

ABSTRACTObjective:To estimate the prevalence of latent Mycobacterium tuberculosis infection (LTBI) in renal transplant recipients and to assess sociodemographic, behavioral, and clinical associations with positive tuberculin skin test (TST) results. Methods:This was a cross-sectional study of patients aged ≥ 18 years who underwent renal transplantation at the Renal Transplant Center of the Federal University of Minas Gerais Hospital das Clínicas, located in the city of Belo Horizonte, Brazil. We included renal transplant recipients who underwent the TST between January 2011 and July 2013. If the result of the first TST was negative, a second TST was administered. Bivariate and multivariate analyses using logistic regression were used to determine factors associated with positive TST results. Results:The sample included 216 patients. The prevalence of LTBI was 18.5%. In the multivariate analysis, history of contact with a tuberculosis case and preserved graft function (estimated glomerular filtration rate ≥ 60 mL/min/1.73 m2) were associated with positive TST results. TST induration increased by 5.8% from the first to the second test, which was considered significant (p = 0.012). Conclusions:The prevalence of LTBI was low in this sample of renal transplant recipients. The TST should be administered if renal graft function is preserved. A second TST should be administered if the first TST is negative.

Immune-mediated inflammatory diseases differently affect IGRAs' accuracy for latent tuberculosis infection diagnosis in clinical practice.

BackgroundClinical accuracy of IGRAs remains unclear on patients with immune-mediated inflammatory diseases (IMIDs). Here, we assess the impact of immunosuppressants and IMIDs on QuantiFERON-TB Gold In-Tube (QFN-G-IT) and T-SPOT.TB accuracy.MethodsPatients with IMIDs who required latent tuberculosis infection (LTBI) screening were enrolled and classified into: (i) 50 patients with inflammatory rheumatic diseases, (ii) 50 patients with psoriasis and (iii) 30 patients with Crohn’s disease. A total of 44 healthy individuals without immunosuppression were also included as controls. Tuberculin skin test (TST), T-SPOT.TB and QFN-G-IT assays were performed. IGRAs were performed following manufacturer’s instructions.ResultsImmunosuppressant’s intake was more frequent on patients with Crohn’s disease and psoriasis. Positive IGRAs and TST results were reduced in Crohn’s disease patients, whereas rate of indeterminate T-SPOT.TB results was increased in this group with respect to the other IMIDs analysed and controls. When IFN-γ response was studied, the levels of this cytokine after mitogen stimulation were significantly lower in Crohn’s and inflammatory rheumatic diseases than in psoriasis. Interestingly, psoriatic patients were the only ones not receiving corticosteroids. Furthermore, a negative correlation was observed between the IFN-γ secreted after mitogen stimulation and corticosteroids dose.ConclusionsIMIDs seem to negatively affect the clinical accuracy of IGRAs, being Crohn’s disease patients the most affected individuals due to their concomitant drug-profile and impaired immune response.

Implementing an isoniazid preventive therapy program for people living with HIV in Thailand.

Treatment of people living with HIV (PLHIV) with latent tuberculosis (TB) infection using isoniazid preventive therapy (IPT) can reduce the risk of TB disease, however, the scale-up of IPT among PLHIV in Thailand and worldwide has been slow. To hasten the implementation of IPT in Thailand, we developed IPT implementation training curricula and tools for health care providers and implemented IPT services in seven large government hospitals. Of the 659 PLHIV enrolled, 272 (41.3%) reported symptoms of TB and 39 (14.3% of those with TB symptoms) were diagnosed with TB. A total of 346 (52.4%) participants were eligible for IPT; 318 (91.9%) of these participants opted to have a tuberculin skin test (TST) and 52 (16.3% of those who had a TST) had a positive TST result. Among the 52 participants with a positive TST, 46 (88.5%) initiated and 39 (75.0%) completed 9 months of IPT: physicians instructed three participants to stop IPT, two participants were lost to follow-up, one chose to stop therapy, and one developed TB. IPT can be implemented among PLHIV in Thailand and could reduce the burden of TB in the country.

Active Tuberculosis Incidence and Characteristics in Patients Treated with Tumor Necrosis Factor Antagonists According to Latent Tuberculosis Infection

This study aimed to determine the incidence and characteristics of active tuberculosis (TB) in patients treated with tumor necrosis factor (TNF) antagonists according to baseline latent tuberculosis infection (LTBI). Data were retrospectively obtained from 702 patients aged ≥20 years treated with TNF antagonists between November 2005 and June 2016 at Severance Hospital, a tertiary referral hospital in Seoul, South Korea. The interferon-gamma release assay (IGRA) with or without a tuberculin skin test (TST) was used to diagnose LTBI. Of the total of 702 patients, LTBI was diagnosed in 255 (36.3%) patients. 23.9% (168/702) had positive IGRA results, and 32.2% (165/512) had positive TST results. Five patients developed active TB after LTBI treatment, and 6 developed TB despite baseline negative LTBI results. After adjustment for age and sex, the standardized TB incidence ratio was 6.01 (95% CI 1.94–14.04) in the LTBI group and 5.14 (95% CI 1.88–11.18) in the baseline negative LTBI group. Clinicians should be aware of the risk of active TB in patients treated with TNF antagonists despite baseline negative LTBI screening results. Regular monitoring and serial tests should be considered during long-term TNF antagonist therapy, especially in intermediate to high TB burden country.

Immunodiagnostic Potential of an In-Vitro Interferon-Gamma Release Assay for Latent Tuberculosis Infection Among Apparently Healthy Individuals in Okada Community, Nigeria

A major challenge in the global Tuberculosis (TB) control is the diagnosis and treatment of Latent Tuberculosis Infection (LTBI). In the absence of any reference standard test for the diagnosis of LTBI, this study set out to compare the performance of the two current immune-based tests, Tuberculin Skin Test (TST) and Quantiferon–TB Gold In–Tube (QFT-GIT) ELISA in the diagnosis of LTBI. Two sets of diagnostic results for 196 apparently healthy volunteers from a cross-section of Okada Community, Edo State, Nigeria were compared in terms of age, occupation, BCG-vaccination status, prior TST and cigarette smoking history. Overall, 56 (28.6%) and 81 (41.3%) of the subjects were diagnosed with LTBI by the QFT-GIT test and TST respectively. The LTBI prevalence as assessed by the QFT-GIT test was significantly higher among the non-BCG-vaccinated, compared to the BCG-vaccinees (X²=18.79, df=1, p=0.0001). The highest concordance (QFT-GIT+ve/TST+ve) was found in the occupation categories (Ʀ=-0.009, p=0.747) and the highest discordance(QFT-GIT –ve/TST +ve) was with respect to the BCG-vaccination status (Ʀ=-0.194, p=0.046).The disparity in the performance of the two tests is attributable to the high false – positive TST results, which is a direct reflection of high (90.8%) BCG vaccination level among the study population. It is advocated that the two-step testing approach, using the QFT-GIT assay as a confirmatory test for LTBI after initial positive screening by the TST, be introduced into the TB control strategy in TB – laden communities with high BCG vaccination coverage.

Comparative Evaluation of Allergodiagnostic of Tuberculosis in Children

The comparative analysis of results of the tuberculin skin test (TST) and of the skin test with the recombinant tuberculosis allergen (Diaskintest - DST) in 7978 children with active tuberculosis revealed for the first time in 2013 - 2014 was carried out. The negative DST result and positive TST result are observed at 551 (6.91%) of patients. 92 patients (1.15%) had negative both tests, and at 98 people (1.23%) DST has yielded positive result, PM - negative. Other patients had positive both tests. In general, by means of DST tuberculosis initially hasn't been revealed at 643 (8.06%) patients, and by means of TST - at 190 (2.38%) patients. The difference is statistically reliable (t = 9.16; P < 0.05). Dynamics of tests results at patients with active tuberculosis was studied. The result of DST remained negative for a year in18.7% of patients, in 26,7% of patients with initially negative DST the result became positive in 3 months, in 2.7% - a year after the first testing. Tuberculosis of various forms and localizations, including TB+, was diagnosed for children with initially negative results of DST and positive TST.

Positive Tuberculin Skin Test Among Health Care Workers: Prevalence and Risk Factors in Teaching Hospitals of a Highly Endemic Region for Tuberculosis, Zahedan, Iran

Background: Tuberculosis (TB) is not only considered as a community acquired disease, but also as an occupational infection. Health care workers (HCWs) in several countries show an increasing pattern for TB. Objectives: The current study aimed to determine the prevalence of positive tuberculin skin test (TST) among HCWs in a highly endemic area for TB in Iran, namely Zahedan, the capital of Sistan and Baluchestan province, located in Southeast of Iran, near the border of Afghanistan. Patients and Methods: In a cross sectional study in 2009, 328 HCWs from all five teaching hospitals in Zahedan were recruited. Inclusion criteria were lack of history of TB in family, receiving BCG vaccination within the first six month after the birth without later booster dose. Age, gender, job, working experience, history of exposure to a known patient with TB and TB vaccine scar were registered. The outcome was positive results during two TSTs (induration > 10 mm). A logistic regression was implemented to determine the predictors of positive TST result. Results: TST was positive in 198 (60.4%) health care workers out of 328. Likelihood of positive TST among HCWs increased in nurses (OR = 4.617, 95% CI = 1.181-18.054, P = 0.028), increasing working experience (OR = 1.178, 95% CI = 1.131 - 1.226, P 0.05). Conclusions: The prevalence of positive TST in HCWs in teaching hospitals in Zahedan is so high. Tuberculosis prevention programs should be implemented for HCWs and personnel of hospitals in Zahedan.

Prevalence of Positive Tuberculin Skin Test (TST) Results among Pre-clinical and Clinical Medical Students during their Educational Course in Mashhad, Iran

Background: Tuberculosis is an endemic and critical public health issue in Iran and many developing countries. Healthcare workers, including medical students are at a great risk of exposure. This study is conducted in order to determine the prevalence of latent tuberculosis infection in medical student in different stages. Materials and Methods: This is a cross sectional study, conducted between August and December 2013. 195 medical students from different stages (preclinical, externship and internship) enrolled in this study. Tuberculin skin testing (TST) was used to determine the prevalence of infection with TB and the induration was measured. A standardized questionnaire was collected for risk-assessment analysis. Original Research Article Habibi and Hajipour; BJMMR, 14(3): 1-5, 2016; Article no.BJMMR.22940 2 Results: Among the 195 participant, 118 (60.5%) had indurations lower than 10 mm and 77 (39.5%) had indurations more than 10 mm. Induration ≥10 mm was taken as positive (P-value<0.0001). Conclusion: TST positive results increase among medical students as they advance in their training program. The screening programs of healthcare student before clinical training can be useful for early identification and treatment of the sporadic cases of latent tuberculosis.