Tuberculosis Exposure Research Articles

Nosocomial tuberculosis exposures at a tertiary care hospital: A root cause analysis

Exposure of health care workers (HCWs) to patients with active TB continues to occur despite implementation of TB control policies. We conducted a root-cause analysis of TB exposures at a tertiary care hospital. Clinical and management details of all confirmed cases identified in 2011 were summarized. Cases were independently reviewed by an expert panel that determined the type (ie, delay in initiating, incorrect use of or premature removal of control measures), preventability, and root cause(s) of each error (exposure). Fifteen cases were reviewed. Ten errors were identified in 7 (47%) cases. Cases associated with errors were older than those without errors (68 y vs 40 y; P = .037). Most cases (12/15) were foreign born. A delay in initiating airborne precautions accounted for 70% (7/10) of the errors. The expert panel determined that 80% (8/10) of the errors were preventable or possibly preventable. The most common root causes were failure to consider TB and failure to obtain and interpret imaging. Advanced age, atypical presentation, and presence of comorbid illnesses were common among the preventable cases. TB control policies do not prevent all exposures. Our findings suggest that consideration of TB in elderly patients with risk factors, even if their signs and symptoms can be explained by an alternative diagnosis or are atypical, followed by a review of imaging studies, can further reduce this risk.

The use of an interferon-gamma release assay to screen for pediatric latent tuberculosis infection in the eastern region of the Emirate of Abu Dhabi

Intense migration to the United Arab Emirates from tuberculosis (TB) high-endemic areas presents a particular risk to the population. Screening for latent tuberculosis infection (LTBI) usually involves risk assessment, the tuberculin skin test (TST), and interferon-gamma release assay (IGRA). This study investigated the use of an IGRA to screen for LTBI and compared its performance with a risk assessment questionnaire. This prospective cross-sectional study was conducted at seven Ambulatory Healthcare Services facilities in Abu Dhabi. Participants (88% Emiratis) were pediatric patients presenting for routine care. The QuantiFERON-TB Gold In-Tube test was performed and the parents completed a questionnaire assessing TB risk factors. Six-hundred and ninety-nine subjects (median age 8.7 years, interquartile range 9.2 years) were enrolled; 669 (96%) agreed to testing. Four patients had a positive IGRA; one had previously been treated for TB, resulting in three patients with LTBI. The estimated LTBI prevalence was 0.45% (95% confidence interval 0.09-1.3). A household contact from a TB high-endemic area was reported in 44%, travel to a TB high-endemic area in 10%, and contact with someone with a chronic cough in 7%, a TB case in 3%, a TST-positive case in 2%, and an IGRA-positive case in 2%. Fifty percent of participants had at least one risk factor. The risk assessment did not predict a positive IGRA. The questionnaire yielded a risk of TB exposure of 50%, however the LTBI prevalence, as defined by the IGRA, was low (0.45%).

“To Treat Sickness Without Understanding the Internal Organs is no Better Than a Blind Man Groping in the Dark”

In this Special Issue of Clinical Anatomy, we focus on the anatomy salient to the very young and the aging. Often, anatomists forget that the anatomy seen in the pediatric and geriatric populations can be unique. Although this is obviously a very large subject, the guest editors, Drs. Watanabe and Asagiri from Kurume University in Japan, have put together a smattering of clinically based topics that will give the reader insight into the body of the pediatric and geriatric populations and their anatomy. As Wang Qingren (1768–1831) stated, “To treat sickness without understanding the internal organs is no better than a blind man groping in the dark” (Shoja et al., 2010). In addition to the content of the Special Issue, additional topics include the ethics of anatomy and two papers on the dangers of the anatomy laboratory in regard to mycobacterium tuberculosis and formaldehyde exposure. Finally, an over two year study on developing a core curriculum for the teaching of anatomy to medical students and headed by Professor Bernard Moxham, the current President of the International Federation of Anatomists, is presented.

Lessons learned from earthquake-related tuberculosis exposures in a community shelter, Japan, 2011

Refugees and displaced populations after natural disasters have been vulnerable to tuberculosis. We report an active pulmonary tuberculosis case at a shelter and the subsequent contact investigation and review lessons learned from the 2011 Great East Japan Earthquake. The contact investigation was conducted to identify latent tuberculosis infection among a total of 95 contact persons, including 78 evacuees at the shelter, who were exposed to the index tuberculosis patient. The association between exposure time of contacts to a patient with active tuberculosis and results of interferon-γ release assay (IGRA) was also examined. IGRA was positive in 9 (12.3%) of 73 evacuees at the shelter. Contacts who were exposed to active tuberculosis for more than 25 days were significantly more likely to be IGRA positive, compared with contacts exposed for less than 20 days. All of the 4 evacuees with latent tuberculosis infection who initiated treatment completed the regimen successfully. When a disaster strikes and many people are living in shelters, it is essential for health care personnel to first suspect tuberculosis and implement prevention and control in collaboration with referral hospitals and public health centers.

Year in review 2013: Lung cancer, respiratory infections, tuberculosis, cystic fibrosis, pleural diseases, bronchoscopic intervention and imaging

This Year in Review examines the most relevant articles published on lung cancer, respiratory infections, tuberculosis (TB), cystic fibrosis (CF), pleural diseases, and interventional pulmonology and imaging in Respirology and other respiratory medicine journals during 2013. Important findings are highlighted with comments in the following sections, each of which was contributed by an author as named in the beginning of each section.

Pneumonia With Chest Wall Invasion in a School-Aged Child.

CASE REPORT The patient is an 11-year-old autistic boy, who presented with a right chest wall mass of unknown duration. Intermittent tactile fever and cough were noted during the 4 days prior to presentation. Retrospectively, the parents noted decreased energy and an unwillingness of the boy to wear his school backpack, associated with complaints of right chest and rib pain over the past several months. He had no weight gain or loss, and no other respiratory symptoms were noted. The boy had a history of periodontal disease, requiring general anesthesia for teeth extractions, and the placement of fillings, crowns, and a spacer 9 months prior to presentation. His immunizations were current and he was not taking any medications. He lived in the suburban Midwest with his parents, both of whom were born in China. He was born in the United States and traveled only domestically to Washington D.C. and Orlando, Florida in the past year. The boy’s parents had never been treated for active or latent tuberculosis. The boy had no other known tuberculosis exposures. There was no relevant family history, including malignancy. There were no household pets or other animal exposures. Physical examination revealed an anxious but well appearing patient. He was afebrile, hemodynamically stable, and saturating well on room air. An 8 × 10 cm firm, immobile mass was noted superior and medial to the right nipple, with overlying erythema and tenderness to touch. Breath sounds were diminished in the right middle and lower lung fields. Crowns were present over the most posterior mandibular molars bilaterally. The surrounding gingival mucosa was healthy and without evidence of inflammation. The remaining exam was unremarkable. A complete blood count was significant for a white blood cell count of 16 K/μL (reference range, 3.5–12.3 K/μL), hemoglobin 9.1 g/dL (reference range, 11.3–15.2 g/dL), and

Modifiable risk factors associated with tuberculosis disease in children in Pune, India.

India accounts for the largest burden of tuberculosis (TB) worldwide, with 26% of the world's cases. To assess the association between novel modifiable risk factors and TB in Indian children. Cases were children aged ≤ 5 years with confirmed/probable TB based on World Health Organization definitions (definition 1). Controls were healthy children aged ≤ 5 years. Logistic regression was performed to estimate the adjusted odds ratio (aOR) of being a TB case given exposure, including indoor air pollution (IAP; exposure to tobacco smoke and/or biomass fuels) and vitamin D deficiency. Cases were re-analyzed according to a new consensus research definition of pediatric TB (definition 2). Sixty cases and 118 controls were enrolled. Both groups had high levels of vitamin D deficiency (55% vs. 50%, P = 0.53). In multivariable analysis, TB was associated with household TB exposure (aOR 25.41, 95%CI 7.03-91.81), household food insecurity (aOR 11.55, 95%CI 3.33-40.15) and IAP exposure (aOR 2.67, 95%CI 1.02-6.97), but not vitamin D deficiency (aOR 1.00, 95%CI 0.38-2.66). Use of definition 2 reduced the number of cases to 25. In multivariate analysis, TB exposure, household food insecurity and IAP remained associated with TB. Household TB exposure, exposure to IAP and household food insecurity were independently associated with pediatric TB.

Low prevalence of positive interferon-gamma tests in HIV-positive long-term immigrants in Norway

To determine the prevalence and predictors of positive interferon-gamma release assays (IGRAs) and tuberculin skin tests (TSTs) in human immunodeficiency virus (HIV) infected patients in Norway, a low tuberculosis (TB) endemic country. Multicentre cross-sectional study of 298 HIV patients tested with QuantiFERON®-TB Gold In-Tube (QFT-GIT), T-SPOT®.TB (T-SPOT) and TST. A total of 77/298 (26%) QFT-GIT, 29/117 (25%) T-SPOT and 52/217 (24%) TSTs (≥ 5 mm) were positive. The median CD4 count was 427 cells/l. Three QFT-GIT results but no T-SPOT results were indeterminate. Of 52 TST-positive patients, 34 (65%) were QFT-GIT-positive (median interferon-gamma [IFN-] 4.38 international units [IU]/ml), compared to 16% of the TST-negative patients (median INF- 0.81 IU/ml, P < 0.001). Origin from a TB-endemic country, previous active TB and TB exposure were associated with a positive QFT-GIT (P 0.01). Patients from TB-endemic countries living in Norway for ≥ 10 years had lower odds of a positive QFT-GIT (12%; OR 0.17, 95%CI 0.060.53, P 0.002) than patients with 03 years' residence (49%). The prevalence of positive IGRAs in HIV-infected patients was high in this low TB endemic setting. Lower QFT-GIT positivity in long-term residents from TB-endemic countries may reflect a waning of TB-specific immune responses.

Increased Severity of Tuberculosis in Guinea Pigs with Type 2 Diabetes: A Model of Diabetes-Tuberculosis Comorbidity

Impaired glucose tolerance and type 2 diabetes were induced in guinea pigs to model the emerging comorbidity of Mycobacterium tuberculosis infection in diabetic patients. Type 2 diabetes mellitus was induced by low-dose streptozotocin in guinea pigs rendered glucose intolerant by first feeding a high-fat, high-carbohydrate diet before M. tuberculosis exposure. M. tuberculosis infection of diabetic guinea pigs resulted in severe and rapidly progressive tuberculosis (TB) with a shortened survival interval, more severe pulmonary and extrapulmonary pathology, and a higher bacterial burden compared with glucose-intolerant and nondiabetic controls. Compared with nondiabetics, diabetic guinea pigs with TB had an exacerbated proinflammatory response with more severe granulocytic inflammation and higher gene expression for the cytokines/chemokines interferon-γ, IL-17A, IL-8, and IL-10 in the lung and for interferon-γ, tumor necrosis factor-α, IL-8, and monocyte chemoattractant protein-1 in the spleen. TB disease progression in guinea pigs with impaired glucose tolerance was similar to that of nondiabetic controls in the early stages of infection but was more severe by day 90. The guinea pig model of type 2 diabetes-TB comorbidity mimics important features of the naturally occurring disease in humans. This model will be beneficial in understanding the complex pathogenesis of TB in diabetic patients and to test new strategies to improve TB and diabetes control when the two diseases occur together.

Prevalence and fungal profile of pulmonary aspergillosis in immunocompromised and immunocompetent patients of a tertiary care hospital

Background<italic>Aspergillus</italic> is a fungus which may present an array of pulmonary manifestations, depending on the patient's immunological and physiological state. Although the incidence of pulmonary aspergillosis occurs primarily in immunocompromised patients but the incidence is also rising in immunocompetent individuals, especially in developing countries.The objective of the study was to determine the prevalence and predisposing factors of pulmonary aspergillosis along with species identification.Materials and MethodsOne hundred and three patients admitted to the Department of Chest and Tuberculosis and in the Department of Medicine from Jan 2012 to Jan 2013 were included in this study. The patients were epitomized on the basis of clinical signs and symptoms, physical examination, chest radiography, CT scans, histopathological examination, bronchoscopy and fungal examination including potassium hydroxide mount, fungal culture of sputum and bronchoalveolar lavage. Species identification was done by colony characteristics, slide culture and Lactophenol Cotton blue mount.ResultsOut of the 103 patients, (63 males and 40 females) <italic>Aspergillus species</italic> has been isolated from 17 (16.5%) males and 07 (6.79%) females. Various predisposing factors of pulmonary aspergillosis have been identified in which pulmonary tuberculosis, chronic smoking and environmental exposure to asbestos, cement its tops the list. Many of the patients had multiple predisposing factors. Aspergillus species were isolated in 24 (23.3%) cases. <italic>Aspergillus fumigatus</italic> was the predominant species isolated in 13 (54.16%) cases followed by <italic>Aspergillus flavus</italic> in 07 (29.16%) cases, <italic>Aspergillus niger</italic> in 03 (12.5%) and <italic>Aspergillus terrus</italic> in 1 (4.16%) cases.It is concluded that the prevalence of pulmonary Aspergillosis is quite high in immunocompromised individuals and low in immunocompetent individuals. An adequate and efficient evaluation of the etiological agents has a crucial role in the management of such patients.

Is ambient air pollution another risk factor of tuberculosis?

Is ambient air pollution another risk factor of tuberculosis?

Editorial Commentary: Understanding BCG Is the Key to Improving It

Editorial Commentary: Understanding BCG Is the Key to Improving It

Frequent Detection of Latent Tuberculosis Infection among Aged Underground Hard Coal Miners in the Absence of Recent Tuberculosis Exposure

BackgroundMiners are at particular risk for tuberculosis (TB) infection due to exposure to silica dust and silicosis. The objectives of the present observational cohort study were to determine the prevalence of latent TB infection (LTBI) among aged German underground hard coal miners with silicosis or chronic obstructive pulmonary disease (COPD) using two commercial interferon-gamma release assays (IGRAs) and to compare their performance with respect to predictors of test positivity.MethodsBetween October 2008 and June 2010, miners were consecutively recruited when routinely attending pneumoconiosis clinics for an expert opinion. Both IGRAs, the QuantiFERON®-TB Gold In-Tube (QFT) and the T-SPOT®.TB (T-SPOT), were performed at baseline. A standardized clinical interview was conducted at baseline and at follow-up. The cohort was prospectively followed regarding the development of active TB for at least two years after inclusion of the last study subject. Independent predictors of IGRA positivity were calculated using logistic regression.ResultsAmong 118 subjects (mean age 75 years), none reported recent exposure to TB. Overall, the QFT and the T-SPOT yielded similarly high rates of positive results (QFT: 46.6%; 95% confidence interval 37.6–55.6%; T-SPOT: 61.0%; 95% confidence interval 52.2–69.8%). Positive results were independently predicted by age ≥80 years and foreign country of birth for both IGRAs. In addition, radiological evidence of prior healed TB increased the chance of a positive QFT result fivefold. While 28 subjects were lost to follow-up, no cases of active TB occurred among 90 subjects during an average follow-up of >2 years.ConclusionsConsidering the high prevalence of LTBI, the absence of recent TB exposure, and the currently low TB incidence in Germany, our study provides evidence for the persistence of specific interferon-gamma responses even decades after putative exposure. However, the clinical value of current IGRAs among our study population, although probably limited, remains uncertain.

TB or not TB?

<scp>TB</scp> or not <scp>TB</scp>?

Impact of cytotoxic and targeted antineoplastic drugs on the validity of the mitogen-induced interferon-gamma release assay for latent tuberculosis infection: Results of a prospective trial at a comprehensive cancer center

Abstract The T-SPOT.TB test (TS.TB), an interferon-gamma (IFN-γ) release assay (IGRA), is superior in diagnosing latent tuberculosis infection compared with the conventional tuberculin skin test (TST). However, whether cytotoxic chemotherapy and treatment with new-generation antineoplastic monoclonal antibodies affects the TS.TB is not certain. We evaluated the feasibility of using the TS.TB in this population. Sixteen cancer patients at high risk for tuberculosis exposure were prospectively evaluated with the TST and TS.TB. Blood samples were obtained 7.5 ± 89.3 days after the most recent cycle of antineoplastic therapy. Six patients (38%) were febrile within 24 h of blood sampling; high-dose corticosteroid therapy and profound treatment-induced neutropenia were present in 1 patient each. In all patients, TS.TB showed no evidence of latent tuberculosis infection. A robust mitogen-induced IFN-γ response was seen in samples from 14 patients (88%) despite therapy with high-dose corticosteroids, cyclophosphamide, fludarabine, gemtuzumab ozogamicin, and alemtuzumab. The presence of fever or profound neutropenia did not negatively impact mitogen response by peripheral lymphocytes. The 2 patients whose peripheral blood lymphocytes (> 500 cells/ml) failed to generate a cytokine response to ex vivo mitogen stimulation had refractory advanced cancer. Unlike the TST, a negative TS.TB provided interpretable results even in cancer patients undergoing new-generation immunosuppressive therapy.

A Teenager Patient With Recurrent Pulmonary Abscesses.

A 15-year-old Hispanic male presented with a history of fever, productive cough, and chest pain for 3 days. He had yellow-orange sputum and complained of chest pain on his left side exacerbated by cough and deep inspiration. Twelve months before the current admission, he was diagnosed with left lower lobe pneumonia with lung abscess. The sputum culture grew methicillin-sensitive Staphylococcus aureus. Hewas treated with intravenous ampicillin-sulbactam for 3 weeks, followed by oral amoxicillin-clavulanate therapy for another 3 weeks. Eight months before the current admission, he was again hospitalized with left lower lobe pneumonia and received treatment with intravenous ceftriaxone for 4 days and oral azithromycin for another 5 days. The patient rapidly clinically improved on these therapies, and no further work up was obtained and no organism was recovered from blood culture. The patient had no history of recent travel, no tuberculosis (TB) exposure, or TB risk factors. He denied smoking or illicit drugs use. He was diagnosed with asthma at 12 years of age and used albuterol inhaler infrequently, namely with exertion. On physical examination, the patient was alert, well nourished, and not in respiratory distress. Vitals signs included a temperature of 36.8°C, pulse 85 beats per minute, respirations 20 breaths per minute, blood pressure 96/60, and oxygen saturation 94% in room air. The patient had a prominent forehead and a broad nasal bridge (Figure 1). Poor dentition and high-arched palate were also visualized (Figure 2). Auscultation of the lungs revealed decreased breath sounds over the left lower lobe. The remainder of the physical examination was unremarkble. White cell count was 9900/mm (range, 4900–13 300/ mm) with a differential of 49%neutrophils, 25% lymphocytes, 6% monocytes, and 20% eosinophils. The C-reactive protein was 61 mg/L (normal, <9.1 mg/L) and sedimentation rate was 19 mm/h (range, 0–14 mm/h). The chest radiograph was remarkable for a cavitary lesion with air fluid level in the left lower lobe. Chest computed tomography confirmed a bi-lobed, thin-walled, fluid-containing cavity 11.9 × 7.2 × 10 cm, located in the left lower lobe with surrounding consolidation. Sputum culture grew Aspergillus fumigatus and Achromobacter denitrificans. The patient was started on intravenous ampicillin-sulbactam treatment. Fluid from a bronchial alveolar lavage revealed nucleated cells of 15,197/mm (85% eosinophils). Bronchial alveolar lavage specimen culture grew Streptococcus mitis and A fumigatus. Bronchial alveolar lavage fluid galactomannan index was 0.8 (normal, <0.5). Based on culture results, therapy was changed to intravenous vancomycin, meropenem, and voriconazole. The patient developed a left hydropneumothorax that required video-assisted thoracic surgery with chest tube insertion. Seven hundred and fifty milliliters of purulent fluid was drained. Due to persistence of hydropneumothorax, a left lower lobectomy was performed. A computed tomography of the paranasal sinuses demonstrated mild mucosal thickening in the sphenoid and maxillary sinuses was noted (Figure 3, right). In addition, multiple un-erupted and partially erupted teeth were noted (Figure 3, left).

Successful Treatment of Mesenteric Scleritis with Prednisone and Azathioprine Combination Therapy in an Elderly Male

Purpose: Sclerosingmesenteritis (SM) also known as, mesenteric panniculitis, retractile mesenteritis or mesenteric fibrosis is a rare fibro inflammatory disorder of unknown etiology that primarily affects the small bowel mesentery. Because of the paucity of published cases the optimal treatment options remained uncertain. Method: A 65-year-old male, with a history of hyperlipidemia, hypertension, diabetes mellitus, gout, and membranous glomerulonephritis, presented with a 6 month history of intermittent abdominal pain, fever, and 20-lbs weight loss. The abdominal pain was generalized, intermittent and dull with no change in his bowel habit. He took daily simvastatin, metoprolol, insulin, and glypizide. He denied history of recent travel overseas or tuberculosis exposure. Physical exam was notable for diffuse generalized abdominal tenderness on palpation but otherwise normal exam. Initial lab work revealed an elevated WBC of 17,000 with 80% Neutrophils, anemia with a Hgb of 9.9. His chem profile was normal with the exception of Cr of 2.5 (his baseline was 2-2.8). He had an elevated ESR and CRP. Infectious work up including urine, blood, and stool cultures, chest X-ray, and PPD test were normal but he was started on empirical antibiotic therapy. A non-contrast CT (due to contrast allergy) was performed which revealed diffuse subtle increased attenuation within the colonic mesenteric fat. Subsequent colonoscopy with random biopsy was performed which was normal. After obtaining surgical consultation, the patient underwent a diagnostic laparoscopy with peritoneal biopsy. Biopsies confirmed the diagnosis of SM with extensive fat necrosis with areas of fibrosis, presence of foamy histiocytes and inflammatory cells with paucity of IgG4-positive plasma cell. Results: Post-operatively he was started on prednisone 50 mg daily for one month and switched to Azathioprine 100 mg with prednisone taper. At 3 months follow-up, he remained afebrile and pain free. His inflammatory markers and WBC had all normalized. Conclusion: Although a relatively benign disease, sclerosing mesenteritis can sometime have a debilitating and fatal course; the need to treat patients with a diagnosis of SM remains debated. Approximately 50% of the patients might not require any treatment however symptomatic patients seem to benefit from treatment. A variety of anti-inflammatory and immunomodulatory agents have been used to treat patients, including steroids, azathioprine, colchicine and tamoxifen, but there is little data on which agents are most successful. In our patient, combination therapy with azathioprine and prednisone taper resulted in significant improvement in the patient's clinical course and lab values.

Impact of cigarette smoking on latent tuberculosis infection: does age matter?

To the Editor: Latent tuberculosis infection (LTBI) is defined by evidence of immunological responses by Mycobacterium tuberculosis proteins in the absence of clinical symptoms/signs of active diseases [1]. People who have increased likelihood of tuberculosis (TB) exposure and those with clinical conditions that increased their risk of progressing from LTBI to TB disease are regarded as high-risk groups for developing TB disease and should be considered for LTBI testing and treatment. Both tuberculin skin test (TST) and T-cell based interferon-γ release assays (IGRAs) are available diagnostic tool for LTBI, but IGRAs avoid the interferences from bacille Calmette–Guerin (BCG) vaccination and non-tuberculous mycobacterium (NTM). Cigarette smoke has adverse effects in respiratory immune function and is widely reported to be associated with an increased risk of respiratory a tract infection, including TB [2, 3]. However, only a few studies investigated the impact of smoking on LTBI, and none of these studies used IGRAs to diagnose LTBI [4, 5]. The European Respiratory Journal recently published a perspective review focused on the role of diagnosis and treatment of LTBI to improve TB control and eventually TB elimination [6]. To eliminate TB on a global scale the identification and sterilisation of latently infected individuals, especially those in high-risk groups, is of paramount importance. Concerning the close correlation between cigarette smoking and active TB, the association between LTBI and smoking deserves further clarification with IGRAs as a diagnostic tool. To elucidate the issue, we enrolled inpatients and outpatients who were considered at risk for LTBI and …

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.

A Toolbox for Tuberculosis (TB) Diagnosis: An Indian Multicentric Study (2006–2008). Evaluation of QuantiFERON-TB Gold in Tube for TB Diagnosis

BackgroundThe aim of this multicentric prospective study in India was to assess the performance of the QuantiFERON TB-Gold in tube (QFT-GIT), Tuberculin Skin Test (TST) and microbiological results as additional tools for diagnosing active tuberculosis (TB) and latent infection (LTBI) according to Human Immunodeficiency Virus (HIV) status.MethodsIndividuals with and without active TB and HIV infection were enrolled between 2006–2008. QFT-GIT and TST results were analyzed per se and in combination with microbiological data.ResultsAmong the 276 individuals (96 active pulmonary TB and 180 no active TB) tested by QFT-GIT, 18 indeterminate results (6.5%) were found, more significantly numerous in the HIV-infected (15/92; 16.3%) than the HIV-uninfected (3/184; 1.6%)(p<0.0001). QFT-GIT sensitivity for active TB was 82.3% and 92.9% respectively after including or excluding indeterminate results. Clinical sensitivity was significantly lower in the HIV-infected (68.4%) than the HIV-uninfected (91.4%) patients (p = 0.0059). LTBI was detected in 49.3% of subjects without active TB but varied according to TB exposure. When the TST and QFT-GIT were concomitantly performed, the respective sensitivity for active TB diagnosis was 95.0% and 85.0% in the HIV-uninfected (p = 0.60), and 66.7% and 51.5% in the HIV-infected patients (p = 0.32). QFT-GIT and TST respective specificity for active TB in the HIV-uninfected was 25.0% and 57.1% (p = 0.028), and 64.8% and 83.3% in the HIV-infected (p = 0.047). In those with active TB, QFT-GIT results were not associated with microbiological parameters (smear grade, liquid culture status, time-to-positivity of culture) or clinical suspicion of active TB score (provided by the clinicians at enrollment). Combining microbiological tests with both immunological tests significantly increased sensitivity for active TB diagnosis (p = 0.0002), especially in the HIV-infected individuals (p = 0.0016).ConclusionQFT-GIT and TST have similar diagnostic value for active TB diagnosis. In HIV-infected patients, combining microbiological tests with both immunological tests significantly increases the sensitivity for active TB diagnosis.