Tuberculin Skin Test Screening Research Articles

Implementation of a Routine Screening Program for Latent Tuberculosis Infection among Patients with Acute Leukemia at a Canadian Cancer Center

Screening for latent tuberculosis infection (LTBI) in patients with hematological malignancy is recommended because of their increased risk of tuberculosis (TB). We assessed the utility of tuberculin skin test (TST) screening in patients with acute leukemia and subsequent outcomes of LTBI treatment. We retrospectively evaluated patients ≥16 years of age with acute leukemia from 2013-2014 with a TST planted and read prior to the initiation of antineoplastic chemotherapy treatment. Demographics, clinical information and treatment outcomes of LTBI therapy were compared between patients with positive TST (≥10 mm induration) and negative TST. A total of 389 patients with acute leukemia were included in the cohort. Of them, 37/389 (9.5%) had a positive TST. Only 3.4% (8/235) of individuals originating from North and South America as well as the Caribbean were TST positive, while 21% (20/95) of individuals from Asia were TST positive. Diagnostic imaging findings consistent with prior tuberculosis infection were higher in TST positive patients compared to TST negative ones (29.7% versus 9.4%, p < 0.0001). Furthermore, 31/38 patients (81.6%) who were TST positive received LTBI therapy, which was well tolerated. There was no significant difference in overall survival among those who received LTBI therapy compared to those who did not. No patients developed active TB. Universal screening with TST may be of low yield in individuals with acute leukemia unless patients originate from a TB endemic country. When therapy for LTBI is prescribed, patients with acute leukemia do not experience drug-induced liver toxicity and are likely to complete the intended duration of therapy, thus preventing the development of active tuberculosis.

Comparing Tuberculin Anergy Skin Test Reactions and Lymphoblastic Transformation in Medical Student

Background: Tuberculin Skin Test (TST) reaction is an accepted screening test for diagnosing acute and latent Tuberculosis (TB) infection among at-risk populations. It is performed with a standard Protein Purified Derivative (PPD) solution. The skin reaction of PPD is unreliable to distinguish natural infection from the Bacillus Calmette Guerin (BCG) effect. The present survey aimed to determine the prevalence of Tuberculin Anergy (TA) reactions among medical students. Accordingly, we evaluated its sensitivity, specificity, and efficiency by applying the Recall Panel Antigen Test (RPAT) and the Lymphoblastic Transformation Test (LTT). Methods: The participants were sequentially enrolled in this study according to the designed protocol. The current study was conducted on healthy medical students before registering for the hospital training course. All research subjects were healthy, having a cicatrix of Bacillus Calmette Guerin (BCG) vaccination on the arm, and at a young age (20-24 years). Results: In total, 180 medical students met the inclusion criteria of the study. The study subjects’ Mean±SD age was 22±3.07 years (male=89, female=91). Moreover, 75 (42%) subjects presented a TA reaction in the first step of TST screening. Furthermore, 13 (64%) individuals presented a negative result of the RPAT. The sensitivity and specificity of the TST reactions, compared with the LTT were 100% and 94.4 %, respectively. Conclusion: Significant TA reactions were found among medical students with positive cicatrix post-vaccinated. The obtained data suggested that the BCG protection for individuals may be decreased as time expired. Consequently, the medical students will especially be at high risk for TB infection during the clinical training course. The collected data highlighted the patient-safety from the viewpoint of forensic medicine.

Risk stratification and management of QuantiFERON-positive solid-organ living donors.

Donor-derived disease with Mycobacterium tuberculosis (MTB) is likely to become more common as donor pools expand due to increasing transplant volume coupled with patterns of migration and global mobility. Our article reviews the current literature and provides a rational approach for clinicians managing the scenario of a living donor who has epidemiologic risk factors for tuberculosis exposure. Tuberculous bacilli, formerly thought to exist latently only in pulmonary granulomas, are now known reside dormant in nonpulmonary organs. Kidney and liver grafts are thus vectors for donor transmitted MTB disease. Donors with elevated risk for latent MTB disease can be identified with tuberculin skin testing or IFN-γ release assay screening in combination with a thorough history to identify risk factors for latent disease. Living donors with an elevated risk for prior MTB exposure provide an opportunity to treat latent disease prior to organ procurement and reduce the risk of donor transmitted disease and secondary morbidity. Improved identification of these high-risk donors can reduce both the incidence of posttransplant MTB disease and the risk of allograft compromise associated with treatment of latent and active disease in posttransplant recipients.

Evaluation of a routine screening program with tuberculin skin testing on rates of detection of latent tuberculosis infection and prevention of active tuberculosis in patients with multiple myeloma at a Canadian cancer centre.

Chemotherapy-induced T cell dysfunction, resulting from treatment of multiple myeloma (mm), enhances the risk for reactivation of latent tuberculous infection (ltbi). However, routine screening for ltbi has its limitations. The objective of the present study was to assess the number of patients treated for ltbi both before and after the introduction of a consistent tuberculin skin test (tst) screening program for patients with mm at our cancer centre. This retrospective observational study analyzed adult patients with mm treated with autologous hematopoietic stem-cell transplantation from 1 January 2013 to 31 December 2014, for whom tst was consistently performed at our cancer facility. Baseline demographic characteristics of patients who received tst testing and ltbi therapy were compared with those of a pre-intervention cohort of patients (1 January 2008 to 31 December 2009) who were not tested. During the post-intervention period, 170 patients with mm had a tst. In 14 patients (8.2%) results were positive, and 11 of the 14 received ltbi therapy. Of another 12 patients with radiographic imaging changes consistent with prior granulomatous disease and negative tst results, 2 were treated. No cases of tuberculosis (tb) reactivation were noted in individuals who completed ltbi therapy. One case of active tb was diagnosed in a patient with a negative tst. In contrast, in the pre-intervention matched cohort of 170 patients, no tsts were performed, and no cases of active tb were documented. Patients with mm could benefit from a consistent tst testing policy coupled with subsequent ltbi therapy. However, universal testing might not be required. A targeted program combining evaluation of host risk factors, imaging findings, and screening tests might optimize ltbi diagnosis and management, and thus be effective in preventing the development of active tb in at-risk patients with mm.

Prevalence of Latent Tuberculosis (LTB) among Household Contacts of Newly Diagnosed Omani Pulmonary Tuberculosis Patients

Background: Oman is a high-income, low prevalent country for tuberculosis disease. Although the rates have remained static over the last decade, the country is aiming for Tuberculosis (TB) elimination. Household contacts of pulmonary TB (PTB) patients form a high-risk group of susceptible individuals who could remain reservoirs of active disease. Objective: A retrospective study was conducted to estimate the prevalence of latent TB infection by Tuberculin Skin Test (TST) or Interferon-Gamma Release Assay (IGRA) screening tests among the household contacts of Omani patients with pulmonary tuberculosis. Design: A cross-sectional survey conducted between 2017 and 2018 of TB cases and their contacts in Muscat Governorate, Oman. Results: Out of the 278 contacts identified, 188 contacts fulfilled the inclusion criteria and were enrolled into the study. The prevalence of Latent Tuberculosis Infection (LTBI) was 22.8% (95% CI: 17.0 - 29.5) among household contacts. We found higher proportions of LTBI among females than males (28.7% vs. 15%, p = 0.027). Those who were exposed to Acid Fast Bacilli (AFB) smear positive cases were more likely to be LTBI (28.7% versus 15% in smear negative cases; p = 0.047). We also found an increasing trend of infection (32.3%) in the oldest age group (46 - 80 years). Conclusion: Besides children, female household contacts and older age contacts should be prioritized for screening as they are more likely to be infected and develop active disease.

The association between tuberculin skin test result and active tuberculosis risk of college students in Beijing, China: a retrospective cohort study

BackgroundAbout 10% latent tuberculosis infections (LTBI) would progress to active tuberculosis (TB), if left prophylactic therapy. Tuberculin skin test (TST) is the most widely used method for LTBI screening in the school of China. However, for college students, the association between TST reaction size and active TB risk was unclear.MethodsWe conducted a retrospective study to assess whether the TST reaction size would predict active TB during the next two years after TST screening for college students. Multivariable Cox regression was performed to identify the size of TST reaction and other factors associated with active TB risk.ResultsA total of 67292 college students in Beijing, China were included in this study; 8021 (11.92%) individuals were TST positive (≥10 mm), and 3879 (5.76%) of them were strong TST positive (≥15 mm). During the two years of follow-up, 26 active TB cases were reported in 134575 person-years with an incidence rate of 19.32 (95% CI: 12.61–28.32) per 100000 person-years. The adjusted hazard ratios (HR) (95% CI) were 1.094 (0.247~4.846), 3.644 (1.188~11.179), 6.832 (2.436~19.163) and 9.768 (2.203~43.315) of cohorts with the TST reaction size intervals 5~9, 10~14, 15~20 and ≥ 20 mm, respectively, compared to cohort with interval 0~4 mm. Besides, the adjusted HR (95% CI) was 3.593 (1.354~9.537) of males compared to females.ConclusionsThis study indicated that the risk of active TB increased in college students when the TST reaction size was ≥10 mm, and males had a higher risk compared to females.

Enduring Challenge of Latent Tuberculosis in Older Nursing Home Residents: A Brief Review.

Tuberculosis (TB) kills almost 4,000 people a day and is competing with human immunodeficiency virus/acquired immune deficiency syndrome (HIV/AIDS) as the most deadly infectious disease in the world. The gold standards of detection and management of latent tuberculosis infection (LTBI) have not been successful in complete eradication of the disease. Current screening modalities of TB include tuberculin skin testing (TST) and/or interferon-γ release assay (IGRA). However, these screening tests have been heavily studied in healthy populations but not in the elderly who are more likely to have multiple risk factors for progression to active TB from LTBI. The largest population that is harboring LTBI is the elderly, specifically those residing in nursing homes. Yet, unfortunately, guidelines for standards of detection and treatment for this specific group are lacking. In this review, we look at TST versus IGRA screening for LTBI in the elderly living in nursing homes. We review a cross-sectional study done at Staten Island University Hospital, and several other assessments of the sensitivity and accuracy of both screening tools. Furthermore, this review looks at the appropriateness of current LTBI treatment and prophylaxis in elderly patients residing in close quarters. The reviews point to the superiority of IGRA testing in the elderly for screening LTBI. The IGRA has been shown to be more sensitive to the detection of LTBI than TST. Additionally, medical complexities that the elderly population possesses may present challenges and resistance to standard treatments of LTBI. It is recommended via the literature that the addition of vitamin D, or alternative therapies (e.g. rifampin) could produce better outcomes for elderly patients with LTBI than the current 9 months of isoniazid (INH). As the older adults represent the fastest growing segment of our population and the largest LTBI reservoir in the USA, revisiting screening and treatment of LTBI in the elderly living in nursing homes may prove to lead to a path of TB eradication once and for all.

A tuberculosis school outbreak in China, 2018: reaching an often overlooked adolescent population.

Adolescents have been largely neglected from tuberculosis control efforts. In low- to medium burden settings much of the tuberculosis burden in this age group occurs from school outbreaks. We report on a large tuberculosis outbreak in adolescents from a boarding high school in Jiangsu Province, China. From March to June 2018, a tuberculosis outbreak occurred in a boarding high school. We conducted an outbreak investigation involving clinical diagnostic tests and molecular analysis to determine the outbreak origin. Cases were detected through symptom screening, tuberculin skin testing (TST), chest radiography, sputum smear, solid sputum culture and GeneXpert MTB/RIF. Mycobacterial interspersed repetitive-unit-variable-number tandem-repeat (MIRU-VNTR) genotyping and spoligotyping methods were performed on Mycobacterium tuberculosis (M. tuberculosis) isolates to identify the outbreak origin. A total of 845 students and 131 teachers/staff attended a TST screening for tuberculosis infection. The prevalence of elevated tuberculin reactions at ≥5, ≥10 and ≥15 mm was 12.19% (119/976), 6.35% (62/976) and 3.28% (32/976), respectively. Radiographic abnormalities were present in 5.73% (56 of 976) individuals, 40 students and 16 teachers/staff. Of these, 12 students were diagnosed with confirmed tuberculosis. In total, 14 students (two index cases and 12 confirmed cases) were diagnosed and reported in the tuberculosis outbreak, an attack rate of 1.7% (14/847) among students (two index cases and 845 screened students). Results from MIRU-VNTR typing and spoligotyping analyses demonstrated that three M. tuberculosis strains belong to the Beijing family with corresponding MIRU-VNTR alleles. This school-based tuberculosis outbreak among adolescents demonstrates that transmission among individuals in this age group is common and must be prioritised. It suggests that identifying and timely diagnosis of smear-positive cases, especially in the early phase of outbreaks, is the key to preventing further spread among close contacts.

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.

Low Prevalence of Active Tuberculosis among High-Risk Pregnant and Postpartum Women in Sweden: A Retrospective Epidemiological Cohort Study Using and Evaluating TST as Screening Method

Objective Studies on the prevalence of active tuberculosis (TB) and latent tuberculosis infection (LTBI) among high-risk pregnant and postpartum women are few and prevalence is not well known. The methods used for diagnosing and treating TB and LTBI also differ both within and between countries. The aim of the study was to investigate the prevalence of TB and LTBI among high-risk pregnant and postpartum women in a Western Region of Sweden using tuberculin skin test (TST) as screening method. Secondary aims were to evaluate the effectiveness of the screening method and possible negative labour and neonatal outcomes among TST-positive women. Methods Pregnant women attending an antenatal care unit (ACU) allocated for TST screening were investigated and followed up for two years postpartum. Results Only one woman out of 902 screened women in the study group was diagnosed with active TB because of TB symptoms and not because of positive TST. 36% of the skin-tested women fulfilled criteria for LTBI. No difference in perinatal outcome was found between women with and without positive TST. Conclusions Our findings suggest that TST screening of high-risk women may not be an effective strategy, since the prevalence of active TB is low. Investigating pregnant and postpartum women with TB symptoms instead of TST for screening could be an option in low TB prevalence areas. The criteria for diagnosing and treating LTBI should be clearly stated.

Management and diagnosis of tuberculosis in solid organ transplant candidates and recipients: Expert survey and updated review,

Background: Optimal screening and management of latent tuberculosis infection (LTBI) and active tuberculosis (TB) in solid organ transplant (SOT) candidates and recipients is necessary to prevent morbidity and mortality.Methods: We conducted a cross-sectional survey of TB and transplant experts across the United States reviewing the clinical practice preferences on key management issues related to LTBI and TB in SOT candidates and recipients.Results: Thirty TB and 13 SOT experts were surveyed (response rate = 53.8%). Both groups agreed that tuberculin skin test (TST) and chest x-ray screening in SOT candidates was useful (78.6% and 84.6%, respectively). TST after SOT was not useful for most transplant experts and TB experts (0% vs. 32.1%, respectively), but both groups were split on usefulness of interferon gamma release assays (IGRA) in SOT recipients (42.9% TB experts vs. 46.2% SOT experts). Most experts recommend LTBI treatment prior to SOT if close monitoring is assured (82.1% TB experts vs. 76.9% transplant experts). LTBI treatment with isoniazid was preferred for patients on calcineurin inhibitors. Evaluation for suspected TB in SOT recipients varied, but most TB experts favored sputum testing (88.9%) whereas most transplant experts favored bronchoscopic testing (69.2%). Preferred TB treatment regimens in SOT recipients were similar to regimens recommended for immunocompetent patients.Conclusions: Most TB and transplant experts recommend evaluation and treatment for LTBI in SOT candidates. Liver transplant candidates, however, should only be treated if close monitoring can be assured and after consulting with a hepatologist. Practice preferences varied regarding the initial diagnostic approach for suspected TB in SOT recipients; however, most experts agreed that SOT recipients should receive similar treatments as immunocompetent patients.

Cost-effectiveness of post-landing latent tuberculosis infection control strategies in new migrants to Canada.

BackgroundThe majority of tuberculosis in migrants to Canada occurs due to reactivation of latent TB infection. Risk of tuberculosis in those with latent tuberculosis infection can be significantly reduced with treatment. Presently, only 2.4% of new migrants are flagged for post-landing surveillance, which may include latent tuberculosis infection screening; no other migrants receive routine latent tuberculosis infection screening. To aid in reducing the tuberculosis burden in new migrants to Canada, we determined the cost-effectiveness of using different latent tuberculosis infection interventions in migrants under post-arrival surveillance and in all new migrants.MethodsA discrete event simulation model was developed that focused on a Canadian permanent resident cohort after arrival in Canada, utilizing a ten-year time horizon, healthcare system perspective, and 1.5% discount rate. Latent tuberculosis infection interventions were evaluated in the population under surveillance (N = 6100) and the total cohort (N = 260,600). In all evaluations, six different screening and treatment combinations were compared to the base case of tuberculin skin test screening followed by isoniazid treatment only in the population under surveillance. Quality adjusted life years, incident tuberculosis cases, and costs were recorded for each intervention and incremental cost-effectiveness ratios were calculated in relation to the base case.ResultsIn the population under surveillance (N = 6100), using an interferon-gamma release assay followed by rifampin was dominant compared to the base case, preventing 4.90 cases of tuberculosis, a 4.9% reduction, adding 4.0 quality adjusted life years, and saving $353,013 over the ensuing ten-years. Latent tuberculosis infection screening in the total population (N = 260,600) was not cost-effective when compared to the base case, however could potentially prevent 21.8% of incident tuberculosis cases.ConclusionsScreening new migrants under surveillance with an interferon-gamma release assay and treating with rifampin is cost saving, but will not significantly impact TB incidence. Universal latent tuberculosis infection screening and treatment is cost-prohibitive. Research into using risk factors to target screening post-landing may provide alternate solutions.

Tuberculin Skin Test Conversions and Occupational Exposure Risk in US Healthcare Workers.

Healthcare workers (HCWs) undergo occupational tuberculosis screening at regular intervals. However, the risk of contracting tuberculosis at the workplace in a setting with a low background tuberculosis incidence is unclear. We aimed to evaluate the risk of tuberculin skin test (TST) conversion and the risk of occupational tuberculosis infection among HCWs in such a setting. We conducted a retrospective cohort study of employees of a large tertiary medical center in the US Midwest who had undergone TST screening during the study period 1 January 1998 to 31 May 2014. Among 40142 HCWs who received a TST, only 123 converted over 16.4 years. Only 9 (7%) of the converters had a suspected tuberculosis exposure at the workplace and none developed active tuberculosis. The majority of TST converters (66%) had a negative QuantiFERON-TB test at the time of the conversion. In one of the largest cohorts of HCWs in a low-tuberculosis-incidence setting, we demonstrated an extremely low risk of occupational tuberculosis exposure among TST converters and no resulting active tuberculosis cases. In this setting, the approach of testing HCWs at baseline and after tuberculosis exposure, rather than at regular intervals, should be considered.

Revisiting annual screening for latent tuberculosis infection in healthcare workers: a cost-effectiveness analysis

BackgroundIn North America, tuberculosis incidence is now very low and risk to healthcare workers has fallen. Indeed, recent cohort data question routine annual tuberculosis screening in this context. We compared the cost-effectiveness of three potential strategies for ongoing screening of North American healthcare workers at risk of exposure. The analysis did not evaluate the cost-effectiveness of screening at hiring, and considered only workers with negative baseline tests.MethodsA decision analysis model simulated a hypothetical cohort of 1000 workers following negative baseline tests, considering duties, tuberculosis exposure, testing and treatment. Two tests were modelled, the tuberculin skin test (TST) and QuantiFERON®-TB-Gold In-Tube (QFT). Three screening strategies were compared: (1) annual screening, where workers were tested yearly; (2) targeted screening, where workers with high-risk duties (e.g. respiratory therapy) were tested yearly and other workers only after recognised exposure; and (3) post exposure-only screening, where all workers were tested only after recognised exposure. Workers with high-risk duties had 1% annual risk of infection, while workers with standard patient care duties had 0.3%. In an alternate higher-risk scenario, the corresponding annual risks of infection were 3% and 1%, respectively. We projected costs, morbidity, quality-adjusted survival and mortality over 20 years after hiring. The analysis used the healthcare system perspective and a 3% annual discount rate.ResultsOver 20 years, annual screening with TST yielded an expected 2.68 active tuberculosis cases/1000 workers, versus 2.83 for targeted screening and 3.03 for post-exposure screening only. In all cases, annual screening was associated with poorer quality-adjusted survival, i.e. lost quality-adjusted life years, compared to targeted or post-exposure screening only. The annual TST screening strategy yielded an incremental cost estimate of $1,717,539 per additional case prevented versus targeted TST screening, which in turn cost an incremental $426,678 per additional case prevented versus post-exposure TST screening only. With the alternate “higher-risk” scenario, the annual TST strategy cost an estimated $426,678 per additional case prevented versus the targeted TST strategy, which cost an estimated $52,552 per additional case prevented versus post-exposure TST screening only. In all cases, QFT was more expensive than TST, with no or limited added benefit. Sensitivity analysis suggested that, even with limited exposure recognition, annual screening was poorly cost-effective.ConclusionsFor most North American healthcare workers, annual tuberculosis screening appears poorly cost-effective. Reconsideration of screening practices is warranted.

Tuberculosis screening among HIV-infected patients: tuberculin skin test vs. interferon-gamma release assay

ABSTRACTNational guidelines recommend screening for latent tuberculosis infection (LTBI) in all HIV-infected patients. Thus, the objective of this study was to measure protocol adherence to national guidelines regarding LTBI screening for HIV-infected patients entering care at an urban primary care clinic specializing in HIV care, identify clinical and other characteristics associated with adherence, and determine whether transitioning from the tuberculin skin test (TST) to the interferon-gamma release assay (IGRA) improved adherence. We conducted a retrospective study using protocol adherence to LTBI screening guidelines within twelve months of entering care at an HIV clinic as the primary outcome. Successful protocol adherence was defined as the placement and reading of a TST, performance of an IGRA, or a note in study clinic records documenting prior testing or treatment for tuberculosis in an outside setting. Multivariable modified Poisson regression models were used in analyses. Overall, 32% (n = 118/372) of patients received LTBI screening within twelve months of entering care. Protocol adherence to LTBI screening guidelines increased from 28% to 37% following the transition from TST to IGRA screening. IGRA screening [adjusted prevalence ratio: 1.45, 95% confidence limits: (1.07, 1.96)], male sex [1.47 (1.05, 2.07)], transfer patient status [1.51 (1.05, 2.18)], and greater than one year of clinic attendance [1.62 (1.06, 2.48)] were independently associated with protocol adherence. Among patients without prior LTBI screening or treatment, patients entering the clinic in 2013 under the IGRA screening protocol were more likely to be screened for LTBI compared to patients entering under the TST screening protocol (34.3% vs. 9.7%, p < 0.001). In conclusion, transitioning from TST to IGRA-based screening improved adherence to screening guidelines. However, further work on improving adherence to LTBI screening guidelines among HIV-infected patients is needed.

Scale-up of collaborative TB/HIV activities in Guyana

ABSTRACTObjective.To assess scale-up of recommended tuberculosis (TB)/HIV activities in Guyana and to identify specific strategies for further expansion.Methods.Medical records and clinic registers were reviewed at nine TB clinics and 10 HIV clinics. At TB clinics, data were collected on HIV testing and antiretroviral therapy (ART) for patients with TB/HIV; at HIV clinics, data were collected on intensified case finding (ICF), tuberculin skin test (TST) results, and provision of isoniazid preventive therapy (IPT).Results.At TB clinics, among 461 patients newly diagnosed with TB, 419 (90.9%) had a known HIV status and 121 (28.9%) were HIV-infected. Among the 63 patients with TB/HIV, 33 (52.4%) received ART. Among the 45 patients with TB/HIV for whom dates of HIV diagnosis were available, 38 (84.4%) individuals knew their HIV status prior to TB diagnosis. At HIV clinics, among 127 patients eligible to receive a TST, 87 (68.5%) received a TST, 66 (75.9%) had a TST result, seven (10.6%) had a newly positive result, two had a previously positive result, and six of nine patients with positive results (66.7%) received IPT. ICF could not be assessed because of incomplete or discrepant documentation.Conclusions.An in-depth evaluation of TB/HIV activities successfully identified areas of success and remaining challenges. At TB clinics, HIV testing rates are high; further scale-up of ART for persons with TB/HIV is needed. At HIV clinics, use of TST to focus IPT is a feasible and efficient strategy; improving rates of annual TST screening will allow for further expansion of IPT.

Prevalence and predictors of latent tuberculosis infection among Italian State Policemen engaged in assistance to migrants: a national cross-sectional study.

ObjectivesBetter knowledge about tuberculosis (TB) and latent TB infection (LTBI) epidemiology is a crucial step for the development of effective strategies towards the control and elimination of this deadliest and persistent health threat. No study has investigated LTBI epidemiology in policemen who act as an interface with cross-border migrants.MethodsA survey to measure the LTBI prevalence and assess the demographic, professional and clinical features potentially associated with tuberculin skin test (TST) positivity was performed in Italian State Police (ISP) employees engaged, even occasionally, in relief activities, hospitality, photographical identification, escorting and accompanying of migrants, regardless of contact with active TB cases. Variables potentially associated with TST positivity were evaluated with univariate and multivariate analysis.ResultsFrom September to December 2014, 4225 ISP workers underwent TST screening and completed the questionnaire for data collection, according to study procedures. The TST was positive in 9.9% of individuals: no active TB cases were registered among the entire study population. Age, previous BCG vaccination and work category resulted independently associated with TST positivity.ConclusionsThis is the first study providing updated data about LTBI epidemiology among ISP employees engaged in assistance to migrants and furnish preliminary evidence of possible associations between TST positivity and different conditions that need to be deeply investigated with prospective studies.

Poor agreement between diagnostic tests for latent tuberculosis infection among HIV-infected persons in Hong Kong.

The tuberculin skin test (TST), T-Spot.TB (T-Spot) and QuantiFERON-TB Gold-In Tube (QFT) were compared in diagnosing latent tuberculosis infection (LTBI) among human immunodeficiency virus (HIV)-infected persons. Human immunodeficiency virus-infected persons without previous history of tuberculosis or LTBI were simultaneously tested by TST, T-Spot and QFT annually and followed up for tuberculosis. Among 110 HIV-infected subjects with 85% previous TST screening coverage, 75% on anti-retroviral therapy, well-preserved median CD4 count (414/μL) and low median viral load (<75/μL), baseline TST, T-Spot and QFT were positive in 5.5%, 5.6% and 4.9%, respectively, with almost complete discordance of positive results. Among 91 (83%), 66 (60%) and 26 (24%) subjects successfully undergoing the first, second and third annual retesting, TST, T-Spot and QFT were, respectively, positive in 11/123 (8.9%), 13/173 (7.5%) and 21/182 (11.5%) on retesting, with similar discordance of positive results. There was no significant association with the concurrent CD4 count or viral load. Conversion occurred in 11/123 (8.9%), 8/160 (5.0%) and 18/168 (10.7%) of TST, T-Spot and QFT, respectively, and none was associated with changes in CD4 count or viral load. More than half of the positive T-SPOT and QFT results reverted to negative on follow-up. None of these tests picked up the single case of culture-confirmed tuberculosis observed after 798 person-years of follow-up. Major discordance in positive results, high reversion rates and low tuberculosis incidence among test-positive subjects cast serious doubt on the utility of the currently available LTBI tests in the annual screening of HIV-infected persons in an intermediate tuberculosis burden area.

Implementation and Operational Research: Feasibility of Using Tuberculin Skin Test Screening for Initiation of 36-Month Isoniazid Preventive Therapy in HIV-Infected Patients in Resource-Constrained Settings.

The tuberculin skin test (TST) can be used to identify HIV-infected people who would benefit the most from long-term isoniazid preventive therapy (IPT). However, in resource-constrained settings, implementation of the TST can be challenging. The objectives of this study were to assess the feasibility of implementing the TST for IPT initiation and to estimate the proportion of TST-positive incidence among HIV-positive patients in 2 high tuberculosis and HIV burden settings. Two prospective observational cohort studies were conducted under programmatic conditions in Mathare, an urban slum of Nairobi, Kenya, and in rural Shiselweni, Swaziland. HIV-positive adults with negative tuberculosis symptomatic screening underwent the TST. Those testing positive were started on 36-month IPT. Of 897 and 1021 patients screened in Mathare and Shiselweni, 550 and 696, respectively, were included. Median age was 38 years, 67.7% were female, and 86.8% were on antiretroviral therapy. Among TST-eligible participants, 88.0% (491/558) and 81.8% (694/848) accepted TST and 74.2% (414/558) and 77.1% (654/858) returned for test reading in Mathare and Shiselweni, respectively. The TST was positive in 49.8% (95% confidence interval: 44.9 to 54.6) in Mathare and 33.2% (95% confidence interval: 29.6 to 36.8) in Shiselweni. The 36-month IPT was accepted by 96.1% (198/206) patients in Mathare and 99.5% (216/217) in Shiselweni. IPT implementation at the clinics was managed with no additional staff or extra space. Implementing the TST for IPT initiation was feasible and acceptable in both urban and rural resource-constrained settings. This strategy allows patients who can benefit the most to receive long-term IPT and avoids unnecessarily treating a significant number of patients who do not stand to benefit.

Prevalence of latent tuberculosis infection in patients with moderate to severe psoriasis taking biologic therapies in a dermatologic private practice in Miami, Florida.

The reactivation of a latent tuberculosis infection is one of the possible major events that may occur during biologic therapies for inflammatory chronic diseases such as psoriasis. Although its main screening test is regularly used in clinical practice, there are few studies about the prevalence of this silent mycobacterial infection and the rate of positive convertors during treatment. To assess the prevalence of latent tuberculosis infection (LTBI) in patients with moderate to severe psoriasis receiving biologic therapy by using tuberculin skin test as a screening method and to evaluate the rate of conversion of tuberculin skin test (TST) during the treatment with biologics. A total of 445 patients were included in our retrospective study, conducted from January 2006 to September 2012. Tuberculin skin test was performed in all patients prior to treatment and once a year during the follow-up. PPD was considered positive with an induration above 5 mm, following the recommendations of Centers for Disease Control and Prevention/ America Thoracic Society. Data analysis was obtained with SPSS 20.0. The prevalence of LTBI in our population before initiating the treatment was 4.5% by using TST screening method. During the treatment, 10 cases that were initially TST-negative became positive. Only one of the patients developed active tuberculosis infection. The other 9 TST-positive patients were detected during the regular annual screening, and no symptoms or findings on chest x-ray were seen. All the patients were treated with isoniazid (INH) for nine months, and biologic therapy was restarted after one month of treatment with INH without development of overt TB infection in any of them during the follow-up period of the study. The mean time to becoming TST positive from start date was 26.7 months (range from 8 months to 5 years). As the PPD was done annually, it is unknown exactly when the patients became TST positive. Prior to initiating treatment, 20 patients were found to be TST positive. All patients had clear chest x-rays and were treated with nine months of INH prior to initiating biologic therapy at least month later. The use of a screening tool for LTBI is mandatory in patients taking biologic therapies to avoid severe infectious complications. Periodic follow-up is also crucial as positive results may be seen after prolonged use of these agents.