Liver transplantation: an unheralded probable risk for tuberculosis.

We present a patient who underwent orthotopic liver transplantation and died of previously undiagnosed pulmonary tuberculosis (TB). TB is known to complicate liver transplantation in rare circumstances. Liver transplantation is an unheralded risk factor for development of TB because of possible activation of latent infection or primary TB in immunosuppressed hosts. A tuberculin skin test should always be performed preoperatively. Preventive treatment with isoniazid is indicated when immunosuppressive therapy is started in patients with high TB risk. Radiographic signs of previous granulomatous disease may be important when tuberculin skin test is negative, unknown or anergy is present. TB is preventable--with a high degree of suspicion where TB is endemic and proactive programs, most TB cases in transplant recipients can be avoided.     

Diagnostic and management challenges for childhood tuberculosis in the era of HIV

The diagnosis and management of childhood tuberculosis (TB) pose substantial challenges in the era of the human immunodeficiency virus (HIV) epidemic. The highest TB incidences and HIV infection prevalences are recorded in sub-Saharan Africa, and, as a consequence, children in this region bear the greatest burden of TB/HIV infection. The tuberculin skin test (TST), which is the standard marker of Mycobacterium tuberculosis infection in immunocompetent children, has poor sensitivity when used in HIV-infected children. Novel T cell assays may offer higher sensitivity and specificity than the TST, but these tests still fail to make the crucial distinction between latent M. tuberculosis infection and active disease and are limited by cost considerations. Symptom-based diagnostic approaches are less helpful in HIV-infected children, because of the difficulty of differentiating TB-related symptoms from those caused by other HIV-associated conditions. Knowing the HIV infection status of all children with suspected TB is helpful because it improves clinical management. HIV-infected children are at increased risk of developing active disease after TB exposure/infection, which justifies the use of isoniazid preventive therapy once active TB has been excluded. The higher mortality and relapse rates noted among HIV-infected children with active TB who are receiving standard TB treatment highlight the need for further research to define optimal treatment regimens. HIV-infected children should also receive appropriate supportive care, including cotrimoxazole prophylaxis, and antiretroviral therapy, if indicated. Despite the difficulties experienced in resource-limited countries, the management of children with TB/HIV infection could be vastly improved by better implementation of readily available interventions.     

Management of tuberculosis in children in low-income countries.

Children become infected when they are exposed to infectious adults with smear-positive tuberculosis (TB). Most children become infected, but few progress to disease (TB). Children at greatest risk of developing disease are those younger than 5 years of age, HIV-infected and severely malnourished. TB is diagnosed in a child when the child has been exposed to an infectious case, has symptoms and a radiological picture suggestive of TB. Children are treated by the DOTS strategy, and can be treated with 6- or 8-month regimens. HIV-infected children are treated with the same regimens. Children under 5 years of age exposed to an infectious case or infected with TB (tuberculin skin test positive) who are asymptomatic must receive preventive chemotherapy (isoniazid for 6 months). Babies born to mothers with active TB must be managed carefully, as they could have congenital TB, and if they do not have TB they will need preventive chemotherapy for 6 months. BCG is indicated in all children soon after birth, except for those with symptomatic HIV infection. The main aim of any TB programme is to prevent the spread of TB, and also the spread to children, which is best achieved by early detection and treatment of adults with smear-positive TB.     

An update on the diagnosis of tuberculosis infection

Targeted testing and treatment of individuals with latent tuberculosis infection at increased risk of progression to active disease is a key element of tuberculosis control. This strategy is limited by the poor specificity of the tuberculin skin test in populations vaccinated with bacille Calmette-Guérin and its low sensitivity in immunosuppressed persons, who are at highest risk of progression. Two blood tests (T-SPOT.TB and QuantiFERON-TB Gold), based on detection of IFN-gamma released by T cells in response to M. tuberculosis-specific antigens, may offer an improvement on the skin test. However, validation is challenging due to the lack of a diagnostic gold standard. This critical appraisal of published evidence summarizes the diagnostic accuracy of the new tests. The blood tests have operational advantages over the skin test because no return visit is required, results are available by the next day, and repeated testing does not cause boosting. Both tests are significantly more specific than the skin test in populations vaccinated with bacille Calmette-Guérin. The data suggest that T-SPOT.TB may be more sensitive than the skin test. Data in groups at high risk of progression to disease are scarce, and more research is needed in these populations, but it is clear that T-SPOT.TB performs better than the skin test in young children and HIV-infected people with active tuberculosis. Incorporation of these tests into programs for targeted testing of latent tuberculosis infection will reduce false-positive and false-negative results inherent in tuberculin testing, equipping clinicians with more accurate tools for tuberculosis control and elimination in the 21st century.     

The risk of tuberculosis in transplant candidates and recipients: a TBNET consensus statement

Tuberculosis (TB) is a possible complication of solid organ and hematopoietic stem cell transplantation. The identification of candidates for preventive chemotherapy is an effective intervention to protect transplant recipients with latent infection with Mycobacterium tuberculosis from progressing to active disease. The best available proxy for diagnosing latent infection with M. tuberculosis is the identification of an adaptive immune response by the tuberculin skin test or an interferon-γ based ex vivo assay. Risk assessment in transplant recipients for the development of TB depends on, among other factors, the locally expected underlying prevalence of infection with M. tuberculosis in the target population. In areas of high prevalence, preventive chemotherapy for all transplant recipients may be justified without immunodiagnostic testing while in areas of medium and low prevalence, preventive chemotherapy should only be offered to candidates with positive M. tuberculosis-specific immune responses. The diagnosis of TB in transplant recipients can be challenging. Treatment of TB is often difficult due to substantial interactions between anti-TB drugs and immunosuppressive medications. This management guideline summarises current knowledge on the prevention, diagnosis and treatment of TB related to solid organ and hematopoietic stem cell transplantation and provides an expert consensus on questions where scientific evidence is still lacking.     

Empfehlungen für das Tuberkulose-Screening vor Gabe von TNF-α-Inhibitoren bei rheumatischen Erkrankungen

Due to the increased risk of tuberculosis (TB) under treatment with TNF-α inhibitors for rheumatoid arthritis and other autoimmune diseases, precautionary measures are required before initiating TNF-α-inhibitor therapy. Patients should have active TB ruled out and screening for latent TB infection should be performed. The screening should include chest X-ray, complete medical history, and the administration of a highly specific interferon-γ-release assay (IGRA). (In the future, the reimbursement of IGRA tests under an analogue procedure code is expected to be formalized by the application of a code specific to the TB-IGRA procedure.) As tuberculin skin test (TST) results can be expected to be either false-positive or false-negative in these patients, the TST, as commonly performed in the past, is recommended only in exceptional situations. For chemopreventive treatment of latent TB infection (LTBI), isoniazid is usually given for 9 months.     

Tuberculosis skin testing and preventive therapy

Tuberculin skin testing is a reliable tool for the detection of tuberculous infection and the eventual prevention of tuberculous disease. False-negative tests may occur in individuals with a compromised immune system, including those with human immunodeficiency virus (HIV) infection, persons taking immunosuppressive drugs (eg. corticosteroids), the severely malnourished, and the elderly. Nevertheless, it still is useful in detecting infection in those persons who are in close contact with patients with tuberculous disease, including family members, hospital personnel, and those from high risk areas. Once a skin test is found to be reactive, further diagnostic studies should be done to rule out tuberculous disease. Once ruled out, preventive therapy with isoniazid should be instituted. Suitable candidates for prophylaxis include all individuals with reactive tuberculin skin tests who are (1) household contacts of patients with tuberculous disease, (2) recent tuberculin test convertors, (3) individuals with prior tuberculosis (TB) who did not receive adequate chemotherapy, (4) all individuals under the age of 35, and (5) individuals in special clinical circumstances who are over the age of 35. Newer, shorter course regimens are currently being studied. TB cannot be eliminated until the importance of preventive therapy is recognized by all.     

Tuberculosis in patients with human immunodeficiency virus infection

Tuberculosis (TB) is the major opportunistic infection of human immunodeficiency virus (HIV)-infected persons worldwide. Human immunodeficiency virus infection is the most potent known risk factor for reactivation of latent Mycobacterium tuberculosis infection, and TB disease appears to increase the rate of HIV progression. Pulmonary disease is seen in most patients, including a large proportion of those with extrapulmonary disease. Failure to suspect TB and to order the appropriate diagnostic tests is the most common reason for diagnostic delays. With advancing HIV infection, tuberculin skin test reactivity decreases along with reactivity to nonspecific antigens such as mumps, tetanus toxoid, and Candida; anergy testing need not be a routine component of tuberculosis screening of HIV-infected persons. The diagnosis depends on identifying the organism on smears or cultures; direct amplification tests may facilitate rapid identification of M. tuberculosis, but the relatively low sensitivity in smear-negative specimens limits their use. Also, these tests must be used in conjunction with the clinical assessment, and they must always be performed in conjunction with microscopy and standard culture. Shorter courses of combination preventive therapy of patients with latent tuberculous infection are effective, but the potential advantages of improved adherence and reduced costs of shorter courses should be balanced with an increased risk secondary to ongoing TB exposure in areas with a high TB prevalence. Six months of treatment for active tuberculosis is recommended, unless the response of a particular patient is slow or otherwise suboptimal. The use of highly active antiretroviral therapy (HAART) made a remarkable impact on the course or HIV disease, but raises several issues with respect to HIV-related TB. Drug interactions necessitate either a non-rifamycin-based regimen or a rifabutin-based regimen in patients on HAART treated for TB.     

Clinical evaluation of QuantiFERON TB-2G test for immunocompromised patients.

The usefulness of the tuberculin skin test (TST) and the QuantiFERON TB-2G (QFT-TB) test were compared in immunocompromised patients. The subjects consisted of 252 immunocompromised patients who were clinically suspected of tuberculosis (TB) infection between April 2005 and December 2006. Regarding the underlying diseases, 74 subjects had malignant diseases, 72 were undergoing immunosuppressive treatment, 52 had diabetes mellitus, 50 had chronic renal failure and four had HIV infection. While the positive rate of the QFT-TB test for the diagnosis of TB infection (TB disease or latent TB infection) was 78.1%, that of TST for TB infection was 50.0%. The QFT-TB test was significantly better than TST. However, 32 (13%) patients had an indeterminate QFT-TB result. Indeterminate findings were significantly more frequent in patients receiving immunosuppressive treatment (28%), especially with lymphocytopaenia in the peripheral blood, than in those who had other underlying diseases. While TST-positive and QFT-TB test-negative results were recognised in immunocompromised patients with bacille Calmette-Guérin vaccination or nontuberculous mycobacterial disease, TST-negative and QFT-TB test-positive results were recognised in immunocompromised patients with a past history of TB infection. It was concluded that the QuantiFERON TB-2G test is a more useful diagnostic method for tuberculosis infection than tuberculin skin test for immunocompromised patients suspected of tuberculosis disease. However, because the results of the QuantiFERON TB-2G test show an indeterminate response for patients receiving immunosuppressive treatment, especially for those with lymphocytopaenia due to severe underlying diseases, care must be taken in the interpretation of the QuantiFERON TB-2G test for these patients.     

Rifapentine, moxifloxacin, or DNA vaccine improves treatment of latent tuberculosis in a mouse model

RATIONALE: Priorities for developing improved regimens for treatment of latent tuberculosis (TB) infection include (1) developing shorter and/or more intermittently administered regimens that are easier to supervise and (2) developing and evaluating regimens that are active against multidrug-resistant organisms. OBJECTIVES AND METHODS: By using a previously validated murine model that involves immunizing mice with Mycobacterium bovis bacillus Calmette-Guérin to augment host immunity before infection with virulent Mycobacterium tuberculosis, we evaluated new treatment regimens including rifapentine and moxifloxacin, and assessed the potential of the Mycobacterium leprae heat shock protein-65 DNA vaccine to augment the activity of moxifloxacin. MEASUREMENTS: Quantitative spleen colony-forming unit counts, and the proportion of mice with culture-positive relapse after treatment, were determined. MAIN RESULTS: Three-month, once-weekly regimens of rifapentine combined with either isoniazid or moxifloxacin were as active as daily isoniazid for 6-9 mo. Six-month daily combinations of moxifloxacin with pyrazinamide, ethionamide, or ethambutol were more active than pyrazinamide plus ethambutol, a regimen recommended for latent TB infection after exposure to multidrug-resistant TB. The combination of moxifloxacin with the experimental nitroimidazopyran PA-824 was especially active. Finally, the heat shock protein-65 DNA vaccine had no effect on colony-forming unit counts when given alone, but augmented the bactericidal activity of moxifloxacin. CONCLUSIONS: Together, these findings suggest that rifapentine, moxifloxacin, and, perhaps, therapeutic DNA vaccination have the potential to improve on the current treatment of latent TB infection.     

Effect of tuberculin skin testing on a Mycobacterium tuberculosis-specific interferon-gamma assay.

Recently, interferon-gamma release assays (IGRA) for specific diagnosis of Mycobacterium tuberculosis infection have become available. In recent UK tuberculosis (TB) guidelines, it has been advised to screen for latent M. tuberculosis infection using the tuberculin skin test (TST), followed by IGRA if the TST is positive. Since TST can boost immune responses to tuberculin, the present authors evaluated whether TST administration affects the result of QuantiFERON-TB Gold in-tube (QFT-GIT), a whole blood-based IGRA. QFT-GIT was performed on the day of TST administration and the day of reading in 15 TST-negative subjects, 46 TST-positive subjects with recent or remote exposure to M. tuberculosis and five cured TB patients. No systematic boosting of QFT-GIT responses from negative to positive was observed. Only in a few TST-positive persons did TST enhance pre-existing QFT-GIT responses. Screening for latent Mycobacterium tuberculosis infection using tuberculin skin testing followed by interferon-gamma release assays on the day of reading is a reliable approach, as the specificity of QuantiFERON-TB Gold in-tube is not affected by prior tuberculin skin test administration.     

Comparison of a whole-blood interferon-gamma assay and tuberculin skin testing in patients with active tuberculosis and individuals at high or low risk of Mycobacterium tuberculosis infection

BACKGROUND: QuantiFeron-TB (QIFN) is a whole-blood interferon-;gamma assay for the recognition of cell-mediated immune response to Mycobacterium tuberculosis infection. OBJECTIVES: To compare the QIFN assay with the tuberculin skin test (TST) in patients with newly diagnosed culture-proven tuberculosis (TB) and healthy volunteers with high or low risk of latent M tuberculosis infection and to identify factors associated with discordance between tests. METHOD: Two-hundred fifty-eight subjects underwent both assays. All participants completed a detailed questionnaire, and data from TB patients' medical records were collected. RESULTS: In the entire study population, agreement between tests was moderate and the correlation between the magnitude of QIFN response and the TST induration diameter was significant. In volunteers with no known risk of exposure to M tuberculosis, the specificity of the assays was comparable. However, in subjects with active TB or those vaccinated with bacille Calmette-Guérin, the QIFN assay detected more reactors than did the TST. In these individuals, agreement between assays was poor and no correlation or only a weak correlation was found between the diameter of TST induration and the magnitude of the interferon-gamma responses. CONCLUSIONS: The sensitivity of the QIFN assay is greater than that of the TST in patients with active TB before the initiation of anti-TB chemotherapy, but its specificity is influenced more by bacille Calmette-Guérin vaccination. The QIFN assay may provide an improvement over the current practice of the use of the TST to support diagnosis of active M tuberculosis infection in the clinic; however, QIFN cannot be considered an adequate replacement for the TST in the screening for latent infection.     

Tuberkulose

Infection with Mycobacterium tuberculosis causes primarily formation of granulomatous tubercles in the lungs. In the absence of any clinical symptoms it is named latent tuberculosis infection which can be an origin of reactivation, especially as a consequence of an impaired response of the immune system. Complete anamnesis, radiographic methods and bacteriological analysis (microscopy, culture, PCR) are useful for diagnosis of tuberculosis. Since 2005 newer in vitro tests are available using interferon-gamma release assays (IGRAs). Compared to the tuberculin skin test it is possible to differentiate between infection with M.?tuberculosis and individuals vaccinated with the Bacillus Calmette-Guérin (BCG) vaccine. These new in vitro tests are part of a screening procedure which has to be performed before starting immunosuppressive therapy with tumor necrosis factor-alpha (TNF-α) inhibitors. In cases of latent tuberculosis infection administration of isoniazid for 9 months is recommended.     

TB status among Kosovar refugees.

DESIGN: In the spring of 1999, 864 Kosovars were directly airborne from refugee camps in Macedonia to a refugee camp in Kristiansand, Norway; 800 were examined according to official Norwegian TB screening procedures with X-ray (if more than 15 years of age) and tuberculin test shortly after arrival. RESULTS: The mean (SD) age was 29.2 (18.7) years of age and 29% were aged under 15 years; 79% of the refugees had escaped from urban areas in Kosovo, and 75% had an identifiable BCG scar. Among those with BCG scar, increasing age and male sex were associated with a significant tuberculin reaction: 20% had tuberculin reactions indicating latent TB infection, while 40% had negative tuberculin reactions. Approximately 4% of the refugees aged over 15 had abnormal chest X-rays, predictive of an enhanced tuberculin reaction. Four refugees had X-ray findings compatible with active TB and were treated with standard four-drug chemotherapy. CONCLUSION: The Kosovar refugees had a high incidence of active tuberculosis (50/100,000). A fifth of the BCG-vaccinated refugees needed careful follow-up to monitor possible progress from latent to active TB infection after immigration, while one in seven non-BCG-vaccinated refugees had tuberculin skin reactions compatible with latent TB infection.     

Factors associated with the treatment of latent tuberculosis infection among health-care workers at a midwestern teaching hospital

STUDY OBJECTIVE: To assess factors associated with initiating therapy and compliance with treatment for latent tuberculosis infection among health-care workers with positive tuberculin skin test results. DESIGN: Prospective cohort study. SETTING: An urban midwestern teaching hospital in St. Louis, MO. Study population: Health-care workers with positive tuberculin skin test results. MEASUREMENTS: (1) Rates of initiating therapy for latent tuberculosis infection among all health-care workers with positive tuberculin skin test results, and (2) compliance rates with therapy for latent tuberculosis infection among health-care workers with recent tuberculin skin test conversion. RESULTS: A total of 440 tuberculin skin test-positive health-care workers were evaluated from January 1, 1994, to May 1, 2000. Of those evaluated, 1 health-care worker had presumed active tuberculosis, 1 had no record of being evaluated, 1 had missing records, and 33 were not recommended isoniazid therapy, leaving 404 workers for analysis. Overall, 396 of 404 health-care workers (98%) with positive tuberculin skin test results initiated isoniazid therapy. In univariate analysis, bacille Calmette-Guérin (BCG) vaccination (p = 0.02) and foreign birth (p = 0.03) were significantly associated with not initiating isoniazid therapy. Compliance data were available for 388 of 404 health-care workers (96%). Of these, 318 of 388 health-care workers (82%) were compliant with 6 months of therapy. BCG vaccination (odds ratio [OR], 3.5; 95% confidence interval [CI], 1.8 to 7.1) and symptoms while receiving therapy (OR, 4.5; 95% CI, 2.0 to 10.1) were significantly associated with noncompliance in multivariate analysis. Among new converters, Asian race (p = 0.006), foreign birth (p = 0.01), BCG vaccination (p = 0.006), and symptoms while receiving therapy (p < 0.001) were significantly associated with noncompliance in univariate analysis. CONCLUSION: This hospital had a high rate of initiating isoniazid therapy for tuberculosis infection among their health-care workers, and a high rate of compliance with therapy. These rates of initiation and completion of isoniazid therapy were much higher than those previously reported in the literature. This may be largely due to a focused program, which includes active follow-up of health-care workers with positive tuberculin skin test results, consisting of physician counseling and monthly phone consultations by nurses, along with free services and medications provided on-site.     

Tuberculosis and hematopoietic stem cell transplant: Review of a difficult and often underestimated problem

Recipients of solid organ transplants (SOT) and stem cell transplants (SCT) constitute a group of patients at risk for tuberculosis (TB) development. The prevalence of active TB in patients undergoing SOT is higher than in patients undergoing SCT, probably due to the shorter period of immunosuppression in the latter. We reviewed the importance of SCT in individuals with hematological malignancies. Most TB cases occur in transplant patients by reactivation of latent infection after immunosuppression, most often within the first year after transplant, leading to graft loss and in some cases, death. Relevant variables to assess the risk of TB infection in a transplant recipient include the donor’s and recipient’s medical histories, imaging results, microbiology and tuberculin skin test (TST) and interferon-gamma release assays (IGRA). TST is routinely performed in the donor and recipient before transplantation. If TST is > 5 mm in the recipient or > 10 mm in the donor, it is necessary to exclude active TB (pulmonary and renal). Chemoprophylaxis is recommended in TST (+) recipients and in recipients with recent seroconversion, in donors with a history of untreated TB or in contact with an individual with active TB, if radiological images are suspicious and the IGRA is (+). The drug of choice is isoniazid. These topics are herewith reviewed.     

采用分子流行病学和传统调查相结合分析嘉祥县某中学结核病聚集性疫情

目的 分析2007-2008年山东省济宁市嘉祥县某中学一起结核病聚集性疫情的情况。 方法 以线索病例为依据,对该校3254名学生进行PPD试验和症状筛查。对分离培养的Mtb进行24位点分枝杆菌散在重复单位-可变数目串联重复序列(Mycobacterial interspersed repetitive unit-variable number tandem repeat,MIRU-VNTR)基因分型分析。采用logistic回归分析法,分析菌阳患者暴露程度和确诊为活动性结核病患者（active tuberculosis,ATB）或潜伏感染者(LTBI)的关系。 结果 筛查该中学学生的Mtb潜伏感染率为28.8%,共确诊10例活动性肺结核患者,其中3例培养阳性。24位点MIRU-VNTR基因分型3株菌株结果显示,2株菌株基因型成簇,1株菌株位点Mutub4、Mtub21和QUB-26拷贝数不同。logistic回归分析结果显示与菌阳患者同班级或同年级是被诊断为ATB或LTBI的危险因素。 结论 该次结核疫情中,3位菌阳患者在学校引起了一定程度的传播,可能导致了另外7例ATB的暴发。因此对学生结核病患者的及时确诊和有效治疗,以及对学生及时进行结核病筛查对控制学校结核病暴发具有重要意义。     

Prevalence and interaction of hepatitis B and latent tuberculosis in Vietnamese immigrants to the United States

OBJECTIVES: Southeast Asian immigrants, with a high prevalence of both hepatitis B and latent tuberculosis, constitute a large proportion of immigrants to the United States. Isoniazid hepatotoxicity may be associated with hepatitis B. This study was conducted to document the prevalence and interaction of hepatitis B, latent tuberculosis, and isoniazid toxicity. METHODS: Hepatitis B surface antigen (HBsAg) and tuberculin skin testing was done on 743 Vietnamese immigrants to the Midwest between January, 1991 and December, 1999. HBsAg positive cases were tested for hepatitis B e antigen (HBeAg). All tuberculin skin test-positive patients were treated with isoniazid, unless contraindicated. Complications of isoniazid treatment and compliance with hepatitis B virus immunization recommendations were evaluated. RESULTS: One hundred three subjects (13.86%) had HBsAg, and 43 (5.7%) HBeAg. Prevalences of latent tuberculosis were similar in HBsAg positive (53%) and HBsAg negative (45%) subjects. Sixty-two percent of HBeAg positive versus 19% of HBeAg negative subjects had hepatotoxic side effects requiring discontinuation of treatment (relative risk [RR] = 11.38, CI = 5.49 < RR < 23.59, p < 0.001). Three cases of severe isoniazid hepatitis occurred in 21 HBeAg positive subjects, versus no cases in 121 HBeAg negative cases treated with isoniazid (RR = 7.72, CI = 5.02 < RR < 11.88, p < 0.001). Only 58% of subjects at risk of developing hepatitis B virus infection were appropriately immunized. CONCLUSIONS: Vietnamese immigrants have a high prevalence of hepatitis B and latent tuberculosis. HBeAg positive cases have a 7.7-fold increased risk of serious isoniazid toxicity and an 11.3-fold increased risk of isoniazid side effects requiring discontinuation of treatment. HBeAg represents an important risk factor for severe isoniazid hepatitis.     

Chemotherapy and diagnosis of tuberculosis

Since after the first streptomycin 1944 trials, anti-tuberculous chemotherapy research has been focused upon establishing drug combination regimens capable of overcoming drug resistance and amenable to ambulatory treatment in resource strapped countries. The first milestone being the 1959 Madras trial comparing home and sanatorium treatment in South India. Subsequently, the MRC trials led Fox and Mitchison to indicate rifampicin, isoniazid and pyrazinamide as the first line drugs for short course, 6 month, regimens and the 1982 Hong Kong Chest Service trials established intermittent therapy as the ambulatory treatment standard for directly observed therapy (DOT). The rising of the HIV epidemic at the beginning of the 1980s has refuelled tuberculosis spread in Africa and Asia and contributed to the expansion of drug-resistant tuberculosis worldwide making the development of new drugs and drug regimens for ambulatory treatment a top priority. Led by biotechnological advances, molecular biology has been brought into TB laboratory diagnosis for the highly sensitive and specific rapid identification of Mycobacterium tuberculosis in biological samples. The field of immunological diagnosis of TB infection, dominated since the early 1900s by the intradermal tuberculin reaction has been put back in motion by the discovery of M. tuberculosis-specific proteins and peptides, now employed in blood tests of high sensitivity and specificity for the diagnosis of latent TB which may help with the identification of contacts at higher risk of active disease and the eradication of epidemic cases.     

Intracutaneous tuberculin test using the Mendel-Mantoux technique. Tuberculin reactivity among inpatients in a pneumology department

Detection of latent tuberculosis infection is an important step in the control of tuberculosis. The tuberculin skin test is the only proven method for identifying tuberculosis infection in patients who do not have tuberculosis disease. The prevalence of tuberculosis infection among hospitalized patients in a pneumological department of an inner-city hospital was evaluated, using the intradermal tuberculin skin test (Mantoux technique). Interpretation of the Mantoux test was based on the size of induration in millimeters and the individual risk profile of the patients, according to the guidelines of the American Thoracic Society and the Centers for Disease Control, revised in 1989. Of 697 tested patients, 252 showed test results consistent with tuberculosis infection (36.2%). 55 of these 697 patients had active tuberculosis disease or a prior history of tuberculosis (7.9%). A positive tuberculin skin test was found in 197 of 642 patients (30.7%) with a diagnosis different from tuberculosis (COPD, pneumonia, cancer and others). In our study, the sensitivity of the tuberculin skin test for active tuberculosis infection was 95%. The present study revealed a high prevalence of tuberculosis infection among hospitalized patients in a pneumological department. Further studies are needed to assess the usefulness of routine tuberculin skin testing in hospitalized populations.