Intermediate Tuberculosis Burden Country Research Articles

Association of duration of undernutrition with occurrence of tuberculosis

Undernutrition is a risk factor of tuberculosis (TB), but the association between duration of undernutrition and occurrence of TB is inconclusive. The objective of this study was to determine whether there is a difference in occurrence of TB according to the duration of undernutrition expressed as accumulated number of underweight in Republic of Korea, an intermediate TB burden country. The National Health Insurance database was used.Eligible subjects were individuals who received a national health examination between 1 and 2009 and 31 December 2010, and who also had received health examinations for four consecutive years prior to 2009.Finally included individuals in the analysis were followed until 31 December 2017. Accumulated number of underweight was defined as the number of times recorded as underweight over four consecutive years. The outcome of the study was newly diagnosed TB according to accumulated number of underweight. Among a study population of 2,396,434, TB was identified in 9,322 (3.89%) cases. The highest accumulated number of underweight was significantly associated with occurrence of TB (adjusted hazard ratio [aHR] 2.563, 95% CI 2.319–2.833). This association remained consistent after adjusting for demographic factors and underlying diseases (aHR 3.326, 95% CI 3.004–3.84). In stratified analysis based on age, sex, diabetes (DM), hypertension (HTN), and waist circumference (WC) in metabolic syndrome (MS), age and sex were identified as effect modifiers. Occurrence of TB was significantly higher in the group with the highest accumulated number of underweight under 65 years of age.

Clinical relevance of false-negative interferon-gamma release assays in patients with tuberculous pleurisy in an intermediate tuberculosis burden country

BackgroundThere have been few studies to verify factors associated with a false-negative interferon-gamma release assay (IGRA) in patients with tuberculous pleurisy. We investigated the clinical relevance of false-negative results of the blood QuantiFERON-TB Gold In-Tube (QFT-GIT) assay and its risk factors in patients diagnosed with pleural tuberculosis (TB).MethodsMedical records of 650 pleural TB patients in a tertiary hospital between January 2009 and December 2020 were reviewed retrospectively. Patients who underwent the blood QFT-GIT assay and pleural fluid analysis before starting anti-TB medication were included.ResultsOf 199 patients with pleural TB who were performed QFT-GIT assay, 36 (18.1%) were false-negative results. These patients tended to be older than those with a positive result (P=0.060). The QFT-GIT-false-negative group of had significantly more comorbidities such as end-stage renal disease (ESRD), haematological cancer or pneumoconiosis than the QFT-GIT-positive group. Hypoproteinaemia and pH >6 in pleural fluid were associated with a false-negative QFT-GIT. Of the 199 patients, 163 (81.9%) were cured or completed anti-TB treatment; 13 patients (6.5%) died. The QFT-GIT-negative patients had significantly worse outcomes including mortality [unfavourable outcome: 33.3% (12/36 patients) in QFT-GIT-negative groups vs. 14.7% (24/163 patients) in QFT-GIT-positive groups, P<0.017; overall mortality: 16.7% (6/36 patients) vs. 4.3% (7/163 patients), respectively, P<0.015].ConclusionsIn pleural TB, a false-negative QFT-GIT result was 18.1% in a country of intermediate TB incidence. This discordant result in GFT-GIT was associated with ESRD, pneumoconiosis, hypoproteinaemia and a poor outcome. Clinicians should keep in mind the possibility of false-negativity in the blood IGRA test, especially in specific situations and its impact on TB outcome in managing patients with pleural TB.

Prevalence of Latent Tuberculous Infection in Patients With Nontuberculous Mycobacterial Lung Disease and Colonization: A Prospective Study in an Intermediate Tuberculosis Burden Country.

BackgroundControlling latent tuberculosis infection (LTBI) is important in eliminating tuberculosis (TB); however, the prevalence of LTBI has rarely been studied in patients with nontuberculous mycobacterial (NTM) lung disease (LD) and colonization (LC).MethodsWe prospectively recruited subjects with NTM isolated from sputum mycobacterial cultures from December 2011 to June 2019. NTM-LD and NTM-LC were defined according to the American Thoracic Society guidelines. Patients with negative cultures were recruited as controls. Patients with a history of active TB or positive TB cultures were excluded. LTBI was confirmed using a QuantiFERON-TB Gold In-tube test. The prevalence and factors associated with LTBI were analyzed.ResultsA total of 406 participants were enrolled, including 171 in the NTM-LD group, 153 in the NTM-LC group, and 82 in the control group. The prevalence of LTBI was higher in the NTM-LD and NTM-LC groups than in the controls (21.6%, 20.9%, and 6.1%; P = .006). Multivariable analysis showed that old age (adjusted odds ratio [aOR], 1.021, per year increment; P = .042), NTM-LD (aOR, 4.030; P = .005), NTM-LC (aOR, 3.610; P = .011, compared with the controls), and pulmonary cavitary lesions (aOR, 3.393; P = .034) were independently associated with LTBI.ConclusionsThe prevalence of LTBI was higher in the patients with NTM-LD and NTM-LC than in the controls. Old age, pulmonary cavitation, and NTM isolated from sputum were associated with a higher risk of LTBI.

The seroconversion rate of QuantiFERON-TB gold in-tube test in psoriatic patients receiving anti-interleukin-23 monoclonal antibodies

Background: Biologic therapies have become the gold standard for the treatment of moderate-to-severe psoriasis and psoriatic arthritis. However, concerns for opportunistic infections exist, especially for tuberculosis (TB) in endemic areas. Previously, tumor necrosis factor inhibitors were reported to carry higher risks of latent TB infection (LTBI) reactivation or new active TB, followed by anti-interleukin (IL)-12/23 and IL-17 agents in Taiwan. Objectives: The objective of the study is to provide real-world clinical rate of seroconversion of serial QuantiFERON-TB gold in-tube (QFT-GIT) tests, for detection of LTBI and newly-acquired TB, in psoriasis patients while receiving IL-23 inhibitors in an intermediate TB burden country. Methods: The local risk management plan required regular monitoring of TB while receiving biologics for psoriasis. This retrospective cohort evaluated consecutive psoriasis patients who received guselkumab or risankizumab between 2015 and 2021 in a tertiary referral center in Taiwan. Results: A total of 144 patients were included, with negative baseline QFT-GIT in 88% and positive in 13%. After receiving at least 6 months of anti-IL-23 drugs, persistently seropositive was found in 15 patients (10%), persistently seronegative in 125 patients (87%), seroconversion in 1 patient (0.6%), and seroreversion in 3 patients (1.9%). The seroconversion rate was 1% (1/127) in individuals under anti-IL-23 medications for at least 12 months. No case of LTBI reactivation was identified. Conclusion: In psoriasis patients under anti-IL-23 therapy, serial interferon-gamma release assays demonstrated a low seroconversion rate (<1%). Anti-IL-23 agents may be a favorable choice for psoriasis patients with a higher risk of TB infection and LTBI reactivation or those who reside in endemic regions.

Effectiveness of Household Contact Investigation with Preventive Therapy for Infectious Tuberculosis in an Intermediate Tuberculosis Burden Country: A Nationwide Investigation

Background: The effect of nationwide household contact (HHC) investigation with tuberculosis (TB) preventive treatment (TPT), including rifampin-resistant TB (RR-TB), in an intermediate TB burden country has not been well evaluated. Moreover, the coverage of HHC investigation with TPT is limited in low-income countries. Thus, it is important to determine the risk factors to identify the priority population for HHC investigation. Methods: This retrospective cohort study analyzed data of HHC participants registered between January 2015 and December 2018 in a linked database of nationwide TB registry and healthcare administrative claims database of South Korea. The primary outcome measure was incident active TB according to the TPT. As secondary outcome measures, we evaluated the risk factors for co-prevalent TB and latent TB infection (LTBI) among HHCs. Findings: We included 119,233 HHCs. TPT completion indicated a lower risk of active TB (adjusted hazard ratio [aHR], 0·14 [95% CI, 0·09–0·22]). Among HHCs of RR-TB patients, there was no significant difference in the risk of active TB between the LTBI-positive with TPT group and the LTBI-negative group (aHR, 2·27 [95% CI, 0·58-8·83]). Male sex, age ≥76 years, contact with first-degree relatives, comorbid chronic pulmonary disease, comorbid diabetes, and alcohol abuse correlated with a higher risk of co-prevalent TB. Further, male sex, contact with first-degree relatives, and comorbid diabetes correlated with a higher risk of LTBI. Interpretation: Nationwide HHC investigation with TPT may effective in an intermediate-TB burden country. Further, HHC with male sex, first-degree relatives, and comorbid diabetes should be prioritized for HHC investigation. Funding Information: Korea Disease Control and Prevention Agency. Declaration of Interests: We declare no competing interests Ethics Approval Statement: This study was approved by the Institutional Review Board (IRB) of Chung-Ang University (IRB number: 1041078-201801-HR-012-01). Informed consent was waived owing to the use of de-identified data.

Frequency of and risk factors for reversion of QuantiFERON test in healthcare workers in an intermediate-tuberculosis-burden country

ObjectivesHigh-risk healthcare workers (HCWs) are often screened for latent tuberculosis infection (LTBI) using QuantiFERON tests (QFTs), with annual serial tests often showing reversion from positive to negative results. We assessed the frequency of and risk factors for reversion of QFTs in HCWs in an intermediate-tuberculosis burden country. MethodsWe enrolled high-risk HCWs at a tertiary-care hospital in South Korea, who were assessed by QFTs at least twice between 2017 and 2019. ResultsOf the 1870 HCWs screened, 1542 (82%) had persistent negative results, 229 (12%) had persistent positive results, 53 (3%) showed reversion, and 46 (2%) showed conversion from negative to positive. Multivariate analysis comparing the characteristics of the 229 HCWs with persistent positive results and the 53 who experienced reversion showed that older age (adjusted odds ratio (aOR): 0.96; 95% confidence interval (CI): 0.92–0.99), male sex (aOR: 0.29; 95% CI: 0.11–0.78) and high (≥0.70 IU/mL) baseline QFT results (aOR: 0.15; 95% CI: 0.07–0.31) were inversely associated with reversion. Using an ROC curve-derived cut-off of <0.738 IU/mL, the area under the curve was 0.79. Of 53 HCWs with reversion, 36 (78%) had below 0.738 IU/mL of baseline QFT, while 181 (79%) of 229 HCWs without reversion had above 0.738 IU/mL of baseline QFT. ConclusionReversion during serial testing is unlikely in HCWs who are male, older in age, and have higher baseline QFT results. Serial testing without LTBI treatment may be indicated in HCWs who are female, younger and, especially, have lower QFT results.

Clinical Characteristics and Radiologic Features of Immunocompromised Patients With Pauci-Bacillary Pulmonary Tuberculosis Receiving Delayed Diagnosis and Treatment.

BackgroundPauci-bacillary pulmonary tuberculosis (TB) can be delayed to diagnose and start anti-TB therapy, especially in immunocompromised patients. We therefore evaluated the clinical and radiologic features of these delayed cases.MethodsImmunocompromised adult patients with pauci-bacillary pulmonary TB were retrospectively enrolled in a tertiary hospital in an intermediate–TB burden country over a 5-year period. We defined “missed TB” or “not-missed TB” patients as those who started anti-TB therapy after or before positive mycobacterial culture results, respectively.ResultsOf 258 patients, 134 (52%) were classified in the missed TB group, and 124 (48%) in the not-missed TB group. Positive results of molecular tests including MTB polymerase chain reaction and/or Xpert TB/RIF were only obtained in the not-missed TB group (54/106, 54%). The median diagnostic delay in the missed TB group was longer than in the other group (30 vs 6 days; P < .001). In the missed TB group, the most common working diagnoses were pneumonia (46, 34%) and lung metastasis of malignancy (40, 30%). Typical radiologic findings for TB, such as upper lobe predominance and centrilobular nodules with tree-in-bud appearance, were less common in the missed TB group than in the other group. Old age (odds ratio [OR], 1.03), solid organ transplant (OR, 3.46), solid tumor (OR, 3.83), and hematologic malignancy (OR, 4.04) were independently associated with missed TB.ConclusionsCare is needed to differentiate pauci-bacillary TB, especially in immunocompromised patients with the mentioned risk factors, even without the usual radiologic features of TB. Additional rapid diagnostic tests to rule out pauci-bacillary TB are urgently needed.

Serial QuantiFERON-TB Gold testing in patients with psoriasis treated with ustekinumab.

BackgroundThere is increasing concern about the risk of latent tuberculosis infection (LTBI) reactivation during the use of biologics for psoriasis. Although ustekinumab had been documented with low risk of tuberculosis, the long-term follow-up of LTBI as determined by QuantiFERON-TB Gold (QFT-G) testing in patients treated with ustekinumab is limited.ObjectivesThis study aims to use serial QFT-G testing as a screening method for detecting LTBI in patients with psoriasis from an intermediate tuberculosis burden country.MethodsThis retrospective review investigated 134 psoriatic patients in whom ustekinumab was prescribed for at least one year between 2010 and 2016 in National Taiwan University Hospital. All patients underwent annular QFT-G testing during ustekinumab therapy.ResultsAmong the 134 enrolled patients, baseline LTBI rate was 13.4% (18/134). Indeterminate QFT-G result was noted in 5.2% (7/134) of patients and 71.4% (5/7) of them turn to be QFT-G negative during the next testing. 81.3% (109/134) of patients had a negative QFT-G at baseline and the seroconversion rate was 7.3% (8/109) in the serial QFT-G. All the patients in the conversion group were referred to a pulmonologist for evaluation and 81.5% (22/27) of them underwent chemoprophylactic therapy while on ustekinumab. No active TB infection was noted during further follow-up with or without chemoprophylaxis.ConclusionsThis study revealed that psoriatic patients receiving long-term ustekinumab therapy had a low QFT-G conversion rate (7.3%). The clinical significance of QFT-G conversion remains controversial and needs larger scale trials to investigate.

The demanding attention of tuberculosis in allogeneic hematopoietic stem cell transplantation recipients: High incidence compared with general population.

BackgroundThe risk of developing tuberculosis (TB) in allogeneic hematopoietic stem cell transplantation (HSCT) recipients is expected to be relatively high in an intermediate TB burden country. This single-center retrospective study was conducted to investigate risk factors and the incidence of TB after allogeneic HSCT.MethodsFrom January 2004 to March 2011, 845 adult patients were enrolled. Starting April 2009, patients were given isoniazid (INH) prophylaxis based on interferon-γ release assay results. The incidence of TB was analyzed before and after April 2009, and compared it with that of the general population in Korea.ResultsTB was diagnosed in 21 (2.49%) of the 845 allogeneic HSCT patients. The median time to the development of TB was 386 days after transplantation (range, 49–886). Compared with the general population, the standardized incidence ratio of TB was 9.10 (95% CI; 5.59–14.79). Extensive chronic graft-versus-host disease (GVHD) was associated with the development of TB (P = 0.003). Acute GVHD, conditioning regimen with total body irradiation and conditioning intensity were not significantly related. INH prophylaxis did not reduce the incidence of TB (P = 0.548). Among 21 TB patients, one patient had INH prophylaxis.ConclusionAllogeneic HSCT recipients especially those who suffer from extensive chronic GVHD are at a high risk of developing TB. INH prophylaxis did not statistically change the incidence of TB, however, further well-designed prospective studies are needed.

Predictive factors for unfavorable outcomes of tuberculous pericarditis in human immunodeficiency virus-uninfected patients in an intermediate tuberculosis burden country.

BackgroundIn areas where Mycobacterium tuberculosis is endemic, tuberculosis is known to be the most common cause of pericarditis. However, the difficulty in diagnosis may lead to late complications such as constrictive pericarditis and increased mortality. Therefore, identification of patients at a high risk for poor prognosis, and prompt initiation of treatment are important in the outcome of TB pericarditis. The aim of this study is to identify the predictive factors for unfavorable outcomes of TB pericarditis in HIV-uninfected persons in an intermediate tuberculosis burden country.MethodsA retrospective review of 87 cases of TB pericarditis diagnosed at a tertiary referral hospital in South Korea was performed. Clinical characteristics, treatment outcomes, complications during treatment, duration of treatment, and medication history were reviewed. Unfavorable outcome was defined as constrictive pericarditis identified on echocardiography performed 3 to 6 months after initial diagnosis of TB pericarditis, cardiac tamponade requiring emergency pericardiocentesis, or death. Predictive factors for unfavorable outcomes were identified.ResultsOf the 87 patients, 44 (50.6%) had unfavorable outcomes; cardiac tamponade (n = 36), constrictive pericarditis (n = 18), and mortality (n = 4). 14 patients experienced both cardiac tamponade and constrictive pericarditis. During a 1 year out-patient clinic follow up, 4 patients required repeat pericardiocentesis and pericardiectomy was performed in 0 patients. In the multivariate analysis, patients with large amounts of pericardial effusion (P = .003), those with hypoalbuminemia (P = .011), and those without cardiovascular disease (P = .011) were found to have a higher risk of unfavorable outcomes.ConclusionHIV-uninfected patients with TB pericarditis are at a higher risk for unfavorable outcomes when presenting with low serum albumin, with large pericardial effusions, and without cardiovascular disease.Electronic supplementary materialThe online version of this article (doi:10.1186/s12879-016-2062-5) contains supplementary material, which is available to authorized users.

Predictive Factors for Unfavorable Outcomes of Tuberculous Pericarditis in Human Immunodeficiency Virus-Uninfected Patients in an Intermediate Tuberculosis Burden Country

In areas where Mycobacterium tuberculosis is endemic, tuberculosis is known to be the most common cause of pericarditis. However, the difficulty in diagnosis may lead to late complications such as constrictive pericarditis and increased mortality. Therefore, identification of patients at a high risk for poor prognosis, and prompt initiation of treatment are important in the outcome of TB pericarditis. The aim of this study is to identify the predictive factors for unfavorable outcomes of TB pericarditis in HIV-uninfected persons in an intermediate tuberculosis burden country. A retrospective review of 87 cases of TB pericarditis diagnosed at a tertiary referral hospital in South Korea was performed. Clinical characteristics, treatment outcomes, complications during treatment, duration of treatment, and medication history were reviewed. Unfavorable outcome was defined as constrictive pericarditis identified on echocardiography performed 3 to 6 months after initial diagnosis of TB pericarditis, cardiac tamponade requiring emergency pericardiocentesis, or death. Predictive factors for unfavorable outcomes were identified. Of the 87 patients, 44 (50.6%) had unfavorable outcomes; cardiac tamponade (n = 36), constrictive pericarditis (n = 18), and mortality (n = 4). 14 patients experienced both cardiac tamponade and constrictive pericarditis. During a 1 year out-patient clinic follow up, 4 patients required repeat pericardiocentesis and pericardiectomy was performed in 0 patients. In the multivariate analysis, patients with large amounts of pericardial effusion (P = .003), those with hypoalbuminemia (P = .011), and those without cardiovascular disease (P = .011) were found to have a higher risk of unfavorable outcomes. HIV-uninfected patients with TB pericarditis are at a higher risk for unfavorable outcomes when presenting with low serum albumin, with large pericardial effusions, and without cardiovascular disease.

PWE-018 Predictive Factors for An Indeterminate Result on Interferon-Gamma Release Assay

Introduction Interferon-gamma (IFN-γ) release assay is used to identify patients with latent tuberculosis prior to biological treatment initiation. A lack of stimulation capacity of lymphocytes by the test control results in an indeterminate result. This is not uncommon in inflammatory bowel disease (IBD) patients receiving immunosuppressive agents. 1,2,3 The aim of this study is to compare the clinical and laboratory characteristics of patients with indeterminate results to those with determinate results. Methods The national database of IBD patients receiving biological agents was accessed. IFN-γ release assay (QuantiFERON-TB Gold) results were noted. Parameters at the time of testing were collected, namely age, diagnosis, disease activity, blood results and drug treatment. Comparisons between the indeterminate group and determinate group were made using IBM® SPSS® Statistics Version 20. The study was approved by the University and Research Ethics Committee of Malta. Results Data from 136 subjects was analysed. 8.8% ( n = 12) had an indeterminate IFN-γ release assay result, 2.2% ( n = 3) had a positive result, while 89% ( n = 121) had a negative result. The indeterminate group had a significantly lower lymphocyte count ( p = 0.041), globulin level ( p = 0.042), immunoglobulin A (IgA) ( p = 0.031) and haemoglobin ( p = 0.016). C-reactive protein was higher in the indeterminate group ( p = 0.024). No significant differences were recorded for age, gender, diagnosis, disease activity, white cell count, neutrophils, platelets, renal/liver function, albumin levels, IgM, IgG, or drug treatment. Critically, only 25% of indeterminate result subjects had a repeat test, all reported as negative. Conclusion Indeterminate results are common in IBD patients, affecting nearly 1 in 10 patients. Patients with low lymphocyte counts, low globulin, low haemoglobin, low IgA and high CRP levels are more likely to have an indeterminate result when tested. The potential of a false negative result is likely to be higher in these patients. One must exert caution when requesting IFN-γ release assays in such IBD patients since the probability of a determinate result may be low. We advise test repetition in all patients with indeterminate results and screening with chest x-ray. References 1 Helwig U, Muller M, Hedderich J, et al, Corticosteroids and immunosuppressive therapy influence the result of QuantiFERON TB Gold testing in inflammatory bowel disease patients . J Crohns and Colitis 2012; 6 :419–424. 2 Jeong SJ, Han SH, Kim CO, et al, Predictive factors for indeterminate result on the QuantiFERON test in an intermediate tuberculosis-burden country . J Infect . 2011; 62 :347–354. 3 Kobashi Y, Sugiu T, Mouri Y, et al , Indeterminate results of QuantiFERON TB-2G test performed in routine clinical practice . Eur Respir J 2009; 33 :812–815. Disclosure of Interest None Declared

Acquired latent tuberculosis infection in psoriasis patients treated with etanercept in the People's Republic of China.

BackgroundTNF-α plays a key role in host defense against mycobacterial infection, and patients receiving TNF-α blocker treatment have increased susceptibility to tuberculosis disease. In the People’s Republic of China, an intermediate tuberculosis-burden country, the latent tuberculosis infection (LTBI) risk in patients with psoriasis who are treated with etanercept, the safest kind of TNF-α blocker, is unknown.ObjectivesThis study reports the LTBI risk in patients with psoriasis after etanercept treatment and aims to answer the question of how often rescreening for LTBI should be done in order to reduce active tuberculosis infection of patients and further reduce the incidence of active tuberculosis disease.Patients and methods:This retrospective review evaluated patients with moderate-to-severe chronic plaque psoriasis between 2009 and 2013. All patients were excluded tuberculosis infection and received etanercept 25 mg twice weekly, then the patients were checked for LTBI 3 months after etanercept treatment to observe the incidence of LTBI and assess the need for rescreening for LTBI every 3 months.ResultsWe retrospectively analyzed 192 patients with psoriasis with moderate-to-severe chronic plaque whose tuberculin skin test and chest X-rays were negative and who received etanercept 25 mg twice weekly. Eighteen of them were excluded because they received less than 3 months of etanercept therapy. After treatment with etanercept, four patients were found to have LTBI.ConclusionIn this study, the incidence of LTBI after 3 months was four in 192 (2.1%), which is higher than the annual incidence of LTBI in the People’s Republic of China (0.72%), so LTBI could be expected to occur within 3 months in psoriasis patients on etanercept. Periodic screening for LTBI in the therapy course, as well as before initiating treatment, is necessary in those patients who use a TNF-α blocker. We recommend rescreening for LTBI every 3 months.

Invasive Pulmonary Aspergillosis-mimicking Tuberculosis.

Pulmonary tuberculosis is occasionally confused with invasive pulmonary aspergillosis (IPA) in transplant recipients, since clinical suspicion and early diagnosis of pulmonary tuberculosis and IPA rely heavily on imaging modes such as computed tomography (CT). We therefore investigated IPA-mimicking tuberculosis in transplant recipients. All adult transplant recipients who developed tuberculosis or IPA at a tertiary hospital in an intermediate tuberculosis-burden country during a 6-year period were enrolled. First, we tested whether experienced radiologists could differentiate pulmonary tuberculosis from IPA. Second, we determined which radiologic findings could help us differentiate them. During the study period, 28 transplant recipients developed pulmonary tuberculosis after transplantation, and 80 patients developed IPA after transplantation. Two experienced radiologists scored blindly 28 tuberculosis and 50 randomly selected IPA cases. The sensitivities of radiologists A and B for IPA were 78% and 68%, respectively (poor agreement, kappa value = 0.25). The sensitivities of radiologists A and B for tuberculosis were 64% and 61%, respectively (excellent agreement, kappa value = 0.77). We then compared the CT findings of the 28 patients with tuberculosis and 80 patients with IPA. Infarct-shaped consolidations and smooth bronchial wall thickening were more frequent in IPA, and mass-shaped consolidations and centrilobular nodules (<10 mm, clustered) were more frequent in tuberculosis. Certain CT findings appear to be helpful in differentiating between IPA and tuberculosis. Nevertheless, the CT findings of about one-third of pulmonary tuberculosis cases in transplant recipients are very close to those of IPA.

Prevalence of latent tuberculosis infection in BCG-vaccinated healthcare workers by using an interferon-gamma release assay and the tuberculin skin test in an intermediate tuberculosis burden country

The risk of healthcare workers (HCWs) acquiring tuberculosis (TB) infection is high. We determined the prevalence of latent TB infection (LTBI) in HCWs with a high Bacille Calmette-Guérin (BCG) vaccine coverage in an intermediate TB burden country by using an interferon-gamma release assay [QuantiFERON-TB Gold (QFT-G)] and by using the tuberculin skin test (TST). Risk factors associated with a positive test were determined. This prospective cross-sectional study enrolled HCWs from a medical center in Taiwan. Participants were grouped into workers without exposure (Group 1) and workers who self-reported a history of TB exposure (Group 2). All participants completed a questionnaire to collect demographic information and risk factors for acquiring TB. The QFT-G test and the TST were administered and risk factors for a positive test were analyzed. We recruited 193 HCWs [149 (77.2%) female workers] with a mean age of 35.6 years. All were BCG-vaccinated. The prevalence of LTBI was 88.8% (based on the TST) and 14.5% (based on the QFT-G test). There was no difference between HCWs with and without known exposure to TB. Agreement between the tests was poor (i.e., the kappa value was less than 0.05). Multivariable logistic regression showed that only the QFT-G test was associated with age (35 years or greater) (adjusted OR, 2.53; p = 0.03). By using the QFT-G test or TST, this study found a similar prevalence of LTBI in HCWs with and without known exposure to TB. This suggests that in intermediate TB burden countries exposure to TB may occur within the hospital and within the community. Compared to the TST, the QFT-G test was correlated better with age, which is a known risk factor for latent TB infection.

Predictive factors for indeterminate result on the QuantiFERON test in an intermediate tuberculosis-burden country

The QuantiFERON-TB Gold In-Tube (QFT-G IT) test is based on the cellular immune response, and this assay can result in indeterminate results for the diagnosis of tuberculosis. The occurrence of indeterminate results may decrease the clinical usefulness of this test. Therefore, we investigated possible predictive factors that can influence the occurrence of indeterminate results from the QFT-G IT test. We conducted a case-control study with 162 case patients who had indeterminate results from a QFT-G IT test at a tertiary hospital in South Korea, from September 2006 to September 2009. Of the 1276 patients, 162 (12.7%) cases that underwent QFT-G IT testing were reported as indeterminate results. Severe lymphopenia (odds ratio [OR] = 8.839; p < 0.001), chronic renal disease (OR = 2.838; p = 0.007), autoimmune disease (OR = 2.527; p = 0.017) and chronic lung disease (OR = 3.169; p = 0.007) were independent predictive factors for indeterminate results from a QFT-G IT test. The patients with lower lymphocyte counts or immunosuppressive conditions showed a higher probability of indeterminate results from the QFT-G IT test. Careful attention to the pre-analytical conditions may be able to minimize this proportion.

Clinical experience of QuantiFERON®-TB Gold testing in patients with psoriasis treated with tumour necrosis factor blockers in Taiwan

In Taiwan, an intermediate tuberculosis burden country, around 9·3% of patients with rheumatoid arthritis treated with adalimumab develop tuberculosis despite prescreening with the tuberculin skin test. Within the Asia-Pacific region, the tuberculosis risk in patients with psoriasis who use tumour necrosis factor (TNF) blockers is unknown. This study reports the use of QuantiFERON(®) -TB Gold (QFT-G) (Cellestis, Melbourne, Vic., Australia) as a screening method for latent tuberculosis infection (LTBI) in patients with psoriasis. This retrospective review evaluated 216 patients with psoriasis in whom TNF blockers were considered between 2004 and 2009 in a tertiary referral hospital in Taiwan. Beginning in 2007, QFT-G was performed on all patients who were candidates for TNF blockers. Seventeen patients who used TNF blockers for less than 4 weeks were excluded. Of the 147 assessed patients receiving TNF blockers, 110 (75%) underwent QFT-G tests. A total of 126 (86%) patients used etanercept and 40 (27%) patients used adalimumab. Nineteen patients switched between both. Overall, patients had a median of 24 weeks (range 4-307) exposure to TNF blockers. Twelve patients (11%) who were treated with TNF blockers and eight (15%) without TNF blockers had positive QFT-G results. Of all TNF blocker users, only one patient (0·68%) developed tuberculosis. QFT-G can be used to screen for LTBI in a tuberculosis endemic area where bacille Calmette-Guérin vaccination coverage is high. Isoniazid prophylaxis is recommended for those who have positive QFT-G test results.

Is the T-cell-Based Interferon-Gamma Releasing Assay Feasible for Diagnosis of Latent Tuberculosis Infection in an Intermediate Tuberculosis-Burden Country?

Is the T-cell-Based Interferon-Gamma Releasing Assay Feasible for Diagnosis of Latent Tuberculosis Infection in an Intermediate Tuberculosis-Burden Country?

The Value of Routinely Culturing for Tuberculosis During Bronchoscopies in an Intermediate Tuberculosis-Burden Country

PurposeMany medical centers routinely culture bronchoscopy samples for Mycobacterium tuberculosis, even when tuberculosis is not strongly suspected. The value of this practice, however, is controversial. We evaluated the role of that procedure in the diagnosis of pulmonary tuberculosis in an intermediate tuberculosis-burden country.Patients and MethodsA prospective, observational study was conducted in a tertiary referral center and included 733 consecutive patients who underwent bronchoscopy examination.ResultsM. tuberculosis was isolated in 47 patients (6.4%). According to radiographic features, the rate of positive culture for M. tuberculosis was relatively high in patients with atelectasis (5/33, 15.2%) and those with pulmonary infiltrations of suspicious infections (26/183, 14.2%). M. tuberculosis was isolated even in patients with pulmonary masses (9/266, 3.4%) and those with pulmonary nodules (5/175, 2.9%). In 16/47 (34.0%) patients with positive cultures for M. tuberculosis, active pulmonary tuberculosis was not suspected at the time of bronchoscopy.ConclusionThese results suggest that routinely culturing for M. tuberculosis during bronchoscopy is still useful in the diagnosis of pulmonary tuberculosis in an intermediate tuberculosis-burden country.