Lost in Space? Unmasking the T Cell Reaction to Simulated Space Stressors.

The space environment will expose astronauts to stressors like ionizing radiation, altered gravity fields and elevated cortisol levels, which pose a health risk. Understanding how the interplay between these stressors changes T cells' response is important to better characterize space-related immune dysfunction. We have exposed stimulated Jurkat cells to simulated space stressors (1 Gy, carbon ions/1 Gy photons, 1 µM hydrocortisone (HC), Mars, moon, and microgravity) in a single or combined manner. Pro-inflammatory cytokine IL-2 was measured in the supernatant of Jurkat cells and at the mRNA level. Results show that alone, HC, Mars gravity and microgravity significantly decrease IL-2 presence in the supernatant. 1 Gy carbon ion irradiation showed a smaller impact on IL-2 levels than photon irradiation. Combining exposure to different simulated space stressors seems to have less immunosuppressive effects. Gene expression was less impacted at the time-point collected. These findings showcase a complex T cell response to different conditions and suggest the importance of elevated cortisol levels in the context of space flight, also highlighting the need to use simulated partial gravity technologies to better understand the immune system's response to the space environment.

Circulating microparticles from subjects with active pulmonary tuberculosis infection modulate immune response.

Microparticles (MPs) which circulate within the plasma are elevated in patients with active pulmonary tuberculosis infection. Circulating MPs isolated from the plasma of patients with active pulmonary tuberculosis infection modulate the cytokine production of immune cells in vitro.

Rapid detection of Mycobacterium tuberculosis DNA and genetic markers for Isoniazid resistance in Ziehl-Neelsen stained slides.

BACKGROUND: Early diagnosis of tuberculosis (TB) and identification of strains of Mycobacterium tuberculosis resistant to anti-TB drugs are considered the main factors for disease control. OBJECTIVES: To standardise a real-time polymerase chain reaction (qPCR) assay technique and apply it to identify mutations involved in M. tuberculosis resistance to Isoniazid (INH) directly in Ziehl-Neelsen (ZN) stained slides. METHODS: Were analysed 55 independent DNA samples extracted from clinical isolates of M. tuberculosis by sequencing. For application in TB diagnosis resistance, 59 ZN-stained slides were used. The sensitivity, specificity and Kappa index, with a 95% confidence interval (CI95%), were determined. FINDINGS: The agreement between the tests was, for the katG target, the Kappa index of 0.89 (CI95%: 0.7-1.0). The sensitivity and specificity were 97.6% (CI95%: 87.7-99.9) and 91.7% (CI95%: 61.5-99.5), respectively. For inhA, the Kappa index was 0.92 (CI95%: 0.8-1.0), the sensitivity and specificity were 94.4% (CI95%: 72.7-99.8) and 97.3% (CI95%: 85.8-99.9), respectively. The use of ZN-stained slides for drug-resistant TB detection showed significant results when compared to other standard tests for drug resistance. MAIN CONCLUSIONS: qPCR genotyping proved to be an efficient method to detect genes that confer M. tuberculosis resistance to INH. Thus, qPCR genotyping may be an alternative instead of sequencing.

Frequency of the Mycobacterium tuberculosis RDRio genotype and its association with multidrug-resistant tuberculosis.

BACKGROUND: In recent decades, Mycobacterium tuberculosis with the RDRio genotype, frequently isolated from tuberculosis patients in Rio de Janeiro, has become part of the Latin American - Mediterranean (LAM) family and has been associated with multidrug-resistant tuberculosis (MDR-TB). The aim of this study was to investigate the frequency of M. tuberculosis RDRio in the state of Minas Gerais, Brazil, and its relationship with MDR-TB. METHODS: For convenience, 172 susceptible and 63 MDR M. tuberculosis isolates were taken from pulmonary samples from patients diagnosed between January 2007 and December 2011. The DNA extracted from these isolates was analyzed by spoligotyping, PCR-RFLP to characterize fbpC103/Ag85C103, multiplex PCR to detect RDRio and RD174, and MIRU-VNTR 24 loci. RESULTS: Among the 235 isolates, the RDRio pattern was identified in 122 (51.9%) isolates (IC 0.45-0.58), with 100 (42.5%) wild-type and 13 (5.5%) mixed pattern isolates, whereas RD174 was identified in 93 of the 122 RDRio positive samples (76.3%). The LAM family and the LAM9 lineage were the most frequently identified among the isolates in this study. Among the 63 MDR isolates, 41 (65.1%) were RDRio and 28 (44.4%) RD174. CONCLUSION: The association of both deletions with MDR proved to be statistically significant, corroborating the few reports that have associated RDRio with MDR.

Multicenter evaluation of TB-SPRINT 59-Plex Beamedex®: accuracy and cost analysis.

BACKGROUND: Molecular tests can allow the rapid detection of tuberculosis (TB) and multidrug-resistant TB (MDR-TB). TB-SPRINT 59-Plex Beamedex® is a microbead-based assay developed for the simultaneous spoligotyping and detection of MDR-TB. The accuracy and cost evaluation of new assays and technologies are of great importance for their routine use in clinics and in research laboratories. The aim of this study was to evaluate the performance of TB-SPRINT at three laboratory research centers in Brazil and calculate its mean cost (MC) and activity-based costing (ABC). METHODS: TB-SPRINT data were compared with the phenotypic and genotypic profiles obtained using Bactec™ MGIT™ 960 system and Genotype® MTBDRplus, respectively. RESULTS: Compared with MGIT, the accuracies of TB-SPRINT for the detection of rifampicin and isoniazid resistance ranged from 81 to 92% and 91.3 to 93.9%, respectively. Compared with MTBDRplus, the accuracies of TB-SPRINT for rifampicin and isoniazid were 99 and 94.2%, respectively. Moreover, the MC and ABC of TB-SPRINT were USD 127.78 and USD 109.94, respectively. CONCLUSION: TB-SPRINT showed good results for isoniazid and rifampicin resistance detection, but still needs improvement to achieve In Vitro Diagnostics standards.

Correlation between the BACTEC MGIT 960 culture system with Genotype MTBDRplus and TB-SPRINT in multidrug resistant Mycobacterium tuberculosis clinical isolates from Brazil.

BACKGROUND: The accurate detection of multidrug-resistant tuberculosis (MDR-TB) is critical for the application of appropriate patient treatment and prevention of transmission of drug-resistant Mycobacterium tuberculosis isolates. The goal of this study was to evaluate the correlation between phenotypic and molecular techniques for drug-resistant tuberculosis diagnostics. Molecular techniques used were the line probe assay genotype MTBDRplus and the recently described tuberculosis-spoligo-rifampin-isoniazid typing (TB-SPRINT) bead-based assay. Conventional drug susceptibility testing (DST) was done on a BACTECTM MGIT 960 TB. METHOD: We studied 80 M. tuberculosis complex (MTC) clinical isolates from Minas Gerais state, of which conventional DST had classified 60 isolates as MDR and 20 as drug susceptible. FINDINGS: Among the 60 MDR-TB isolates with MGIT as a reference, sensitivity, specificity, accuracy, and kappa for rifampicin (RIF) resistance using TB-SPRINT and MTBDRplus, were 96.7% versus 93.3%, 100.0% versus 100.0%, 97.5% versus 95.0% and 0.94 versus 0.88, respectively. Similarly, the sensitivity, specificity, accuracy, and kappa for isoniazid (INH) resistance were 85.0% and 83.3%, 100.0% and 100.0%, 88.8% and 87.5% and 0.74 and 0.71 for both tests, respectively. Finally, the sensitivity, specificity, accuracy, and kappa for MDR-TB were 85.0% and 83.3%, 100.0% and 100.0%, 88.8% and 87.5% and 0.74 and 0.71 for both tests, respectively. MAIN CONCLUSIONS: Both methods exhibited a good correlation with the conventional DST. We suggest estimating the cost-effectiveness of MTBDRplus and TB-SPRINT in Brazil.

Evaluation of the impact of pharmaceutical care for tuberculosis patients in a Secondary Referral Outpatient Clinic, Minas Gerais, Brazil.

Pharmaceutical care is a professional practice seeking the responsible provision of drug therapy by identifying, resolving, and preventing Drug-Related Problems (DRP). The study aims to describe and evaluate the impact of pharmaceutical care given to patients being treated for tuberculosis (TB). Study concurrent, longitudinal, prospective conducted during pharmaceutical care in the TB outpatient clinic, Clinical Hospital, Federal University of Minas Gerais during the period August 2009 to July 2012. The Pharmacotherapy Workup proposed by Cipolle et al. (2004) was used. Statistical analyses were performed by X2 or Fisher exact test, as appropriate. A total of 62 patients were followed up, and 128 drug-related problems (DRP) were identified: 69.5% related to safety, 13.3% to effectiveness, 12.5% ​​to indication, and 4.7% to treatment adherence, and 62.1% of the DRP were resolved. A total of 115 pharmaceutical interventions were performed. The impact of pharmaceutical care was satisfactory for 73.9% of patients with a resolution rate of 77%. There was a greater impact on pharmaceutical care (index ≥ 0.50) for those patients who were not smokers (p <0.05). The impact of pharmaceutical care was important, so the pharmacist should work alongside the multidisciplinary team to monitor treatment and perform interventions.

Genetic diversity and molecular epidemiology of multidrug-resistant Mycobacterium tuberculosis in Minas Gerais State, Brazil.

BACKGROUND: We aimed to characterize the genetic diversity of drug-resistant Mycobacterium tuberculosis (MTb) clinical isolates and investigate the molecular epidemiology of multidrug-resistant (MDR) tuberculosis from Minas Gerais State, Brazil. METHODS: One hundred and four MTb clinical isolates were assessed by IS6110-RFLP, 24-locus mycobacterial interspersed repetitive units variable-number tandem repeats (MIRU-VNTR), TB-SPRINT (simultaneous spoligotyping and rifampicin-isoniazid drug-resistance mutation analysis) and 3R-SNP-typing (analysis of single-nucleotide polymorphisms in the genes involved in replication, recombination and repair functions). RESULTS: Fifty-seven different IS6110-RFLP patterns were found, among which 50 had unique patterns and 17 were grouped into seven clusters. The discriminatory index (Hunter and Gaston, HGDI) for RFLP was 0.9937. Ninety-nine different MIRU-VNTR patterns were found, 95 of which had unique patterns and nine isolates were grouped into four clusters. The major allelic diversity index in the MIRU-VNTR loci ranged from 0.6568 to 0.7789. The global HGDI for MIRU-VNTR was 0.9991. Thirty-two different spoligotyping profiles were found: 16 unique patterns (n = 16) and 16 clustered profiles (n = 88). The HGDI for spoligotyping was 0.9009. The spoligotyped clinical isolates were phylogenetically classified into Latin-American Mediterranean (66.34 %), T (14.42 %), Haarlem (5.76 %), X (1.92 %), S (1.92 %) and U (unknown profile; 8.65 %). Among the U isolates, 77.8 % were classified further by 3R-SNP-typing as 44.5 % Haarlem and 33.3 % LAM, while the 22.2 % remaining were not classified. Among the 104 clinical isolates, 86 were identified by TB-SPRINT as MDR, 12 were resistant to rifampicin only, one was resistant to isoniazid only, three were susceptible to both drugs, and two were not successfully amplified by PCR. A total of 42, 28 and eight isolates had mutations in rpoB positions 531, 526 and 516, respectively. Correlating the cluster analysis with the patient data did not suggest recent transmission of MDR-TB. CONCLUSIONS: Although our results do not suggest strong transmission of MDR-TB in Minas Gerais (using a classical 100 % MDR-TB identical isolates cluster definition), use of a smoother cluster definition (>85 % similarity) does not allow us to fully eliminate this possibility; hence, around 20-30 % of the isolates we analyzed might be MDR-TB transmission cases.

In-house PCR with DNA extracted directly from positive slides to confirm or exclude the diagnosis of tuberculosis: focus on biosafety.

The possibility to obtain DNA from smears is a valuable alternative to remedy the lack of samples when they are totally used for bacilloscopy; this technique solves the biosafety problem related to a possible accident with the transportation of flasks containing potentially transmissible clinical samples. Hence, the purpose of this study was to utilize the insertion sequence IS6110 for amplification of DNA from a smear-positive sample for tuberculosis (TB) diagnosis. Among the 52 positive bacilloscopies, sensitivity, specificity, positive predictive value and negative predictive value were 52.3%, 100%, 100% and 89.7%, respectively whereas accuracy was 90.7%. The IS6110-based PCR for TB diagnosis developed in DNA extracted from a positive smear is a fast, simple, specific, and safe method.

Radiation-induced DNA double-strand breaks in cortisol exposed fibroblasts as quantified with the novel foci-integrated damage complexity score (FIDCS).

Without the protective shielding of Earth's atmosphere, astronauts face higher doses of ionizing radiation in space, causing serious health concerns. Highly charged and high energy (HZE) particles are particularly effective in causing complex and difficult-to-repair DNA double-strand breaks compared to low linear energy transfer. Additionally, chronic cortisol exposure during spaceflight raises further concerns, although its specific impact on DNA damage and repair remains unknown. This study explorers the effect of different radiation qualities (photons, protons, carbon, and iron ions) on the DNA damage and repair of cortisol-conditioned primary human dermal fibroblasts. Besides, we introduce a new measure, the Foci-Integrated Damage Complexity Score (FIDCS), to assess DNA damage complexity by analyzing focus area and fluorescent intensity. Our results show that the FIDCS captured the DNA damage induced by different radiation qualities better than counting the number of foci, as traditionally done. Besides, using this measure, we were able to identify differences in DNA damage between cortisol-exposed cells and controls. This suggests that, besides measuring the total number of foci, considering the complexity of the DNA damage by means of the FIDCS can provide additional and, in our case, improved information when comparing different radiation qualities.

Brazilian Thoracic Association recommendations for the management of post-tuberculosis lung disease.

Historically, all efforts against tuberculosis were focused on rapid diagnosis and effective treatment to break the chain of transmission of Mycobacterium tuberculosis. However, in the last few years, more and more evidence has been found on the dramatic consequences of the condition defined as post-tuberculosis lung disease (PTLD). Approximately one third of patients surviving pulmonary tuberculosis face considerable ongoing morbidities, including respiratory impairment, psychosocial challenges, and reduced health-related quality of life after treatment completion. Given the important global and local burden of tuberculosis, as well as the estimated burden of PTLD, the development of a consensus document by a Brazilian scientific society-Sociedade Brasileira de Pneumologia e Tisiologia (SBPT)-was considered urgent for the prevention and management of this condition in order to allocate resources to and within tuberculosis services appropriately and serve as a guide for health care professionals. A team of eleven pulmonologists and one methodologist was created by the SBPT to review the current evidence on PTLD and develop recommendations adapted to the Brazilian context. The expert panel selected the topics on the basis of current evidence and international guidelines. During the first phase, three panel members drafted the recommendations, which were divided into three sections: definition and prevalence of PTLD, assessment of PTLD, and management of PTLD. In the second phase, all panel members reviewed, discussed, and revised the recommendations until a consensus was reached. The document was formally approved by the SBPT in a special session organized during the 2023 SBPT Annual Conference.

A Dusty Road for Astronauts.

The lunar dust problem was first formulated in 1969 with NASA's first successful mission to land a human being on the surface of the Moon. Subsequent Apollo missions failed to keep the dust at bay, so exposure to the dust was unavoidable. In 1972, Harrison Schmitt suffered a brief sneezing attack, red eyes, an itchy throat, and congested sinuses in response to lunar dust. Some additional Apollo astronauts also reported allergy-like symptoms after tracking dust into the lunar module. Immediately following the Apollo missions, research into the toxic effects of lunar dust on the respiratory system gained a lot of interest. Moreover, researchers believed other organ systems might be at risk, including the skin and cornea. Secondary effects could translocate to the cardiovascular system, the immune system, and the brain. With current intentions to return humans to the moon and establish a semi-permanent presence on or near the moon's surface, integrated, end-to-end dust mitigation strategies are needed to enable sustainable lunar presence and architecture. The characteristics and formation of Martian dust are different from lunar dust, but advances in the research of lunar dust toxicity, mitigation, and protection strategies can prove strategic for future operations on Mars.

Cost analysis of GenoType® MTBDRplus and GenoType® MTBDRsl at the State Laboratory of São Paulo, Brazil.

BACKGROUND: We aimed to evaluate the costs of GenoType® MTBDRplus and MTBDRsl incurred during the diagnosis of first- and second-line drug-resistant tuberculosis (TB) in São Paulo, Brazil. METHODS: Mean and activity-based costs of GenoType® were calculated in a referral laboratory for TB in Brazil. RESULTS: The mean cost value and activity-based cost of GenoType® MTBDRplus were USD 19.78 and USD 35.80 and those of MTBDRsl were USD 54.25 and USD 41.85, respectively. CONCLUSIONS: The cost of GenoType® MTBDRplus was reduced owing to the high number of examinations performed and work optimization.

Gait analysis of leprosy patients with foot drop using principal component analysis.

BACKGROUND: Peripheral nerve injury caused by leprosy can lead to foot drop, resulting in an altered gait pattern that has not been previously described using 3D gait analysis. METHODS: Gait kinematics and dynamics were analyzed in 12 patients with unilateral foot drop caused by leprosy and in 15 healthy controls. Biomechanical data from patients' affected and unaffected limbs were compared with controls using inferential statistics and a standard distance, based on principal components analysis (PCA). FINDINGS: Patients walked slower than controls (0.8 ± 0.2 vs. 1.1 ± 0.2 m/s, p = 0.003), with a reduced stance and increased swing percentage. The affected limb increased (p < 0.05) plantar flexion at the initial contact (-16.8o ± 8.3), terminal stance (-29.1o ± 11.5), and swing (-12.4o ± 6.2) in the affected limb compared to unaffected (-6.6o ± 10.3; -14.6o ± 11.6; 2.4o ± 7.6) and controls (-5.4o ± 2.5; -18.8o ± 5.8; -1.4o ± 3.9). Increased pelvic tilt and knee adduction/abduction range, with lower hip adduction, were observed. The second peak of ground reaction force (98.6 ± 5.2 %BW), ankle torque (0.99 ± 0.33 Nm/kg), and net ankle work in stance (-0.03 ± 5.4 J/Kg) decreased in the affected limb compared to controls (104.1 ± 5.5 %BW; 1.24 ± 0.4 Nm/kg; -4.58 ± 5.19 J/kg; p < 0.05). There were decreasing multivariate standard distances in the affected limb compared with the unaffected and controls. PCA loading factors highlighted the major differences between groups. INTERPRETATION: Leprosy patients with foot drop presented altered gait patterns in affected and unaffected limbs. There were remarkable differences in ankle kinematics and dynamics. Rehabilitation devices, such as ankle foot orthosis or tendon transfer surgeries to increase ankle dorsiflexion, could benefit these patients and reduce deviations from normal gait.

Factors Associated with the Effectiveness of Regimens for the Treatment of Tuberculosis in Patients Coinfected with HIV/AIDS: Cohort 2015 to 2019.

(1) Background: Infection with the Human Immunodeficiency Virus (HIV) is a significant challenge for tuberculosis (TB) control, with increasing mortality rates worldwide. Moreover, the loss to follow-up is very high, with low adherence to treatment, resulting in unfavorable endpoints. This study aimed to analyze the effectiveness of TB treatment in patients coinfected with HIV/AIDS and its associated factors. (2) Methods: Patients coinfected with TB and HIV/AIDS at a Reference Hospital for infectious diseases were followed up for a maximum of one year from the start of TB treatment until cure or censorship (death, abandonment, and transfer) from 2015 to 2019. The Cox proportional model was used to identify risk factors for effectiveness. (3) Results: Of the 244 patients included in the cohort, 58.2% (142/244) had no treatment effectiveness, 12.3% (30/244) died, and 11.1% (27/244) abandoned treatment. Viral suppression at the onset of TB treatment (HR = 1.961, CI = 1.123-3.422), previous use of Antiretroviral Therapy (HR = 1.676, CI = 1.060-2.651), new cases (HR = 2.407, CI = 1.197-3.501), not using illicit drugs (HR = 1.763, CI = 1.141-2.723), and using the basic TB regimen (HR = 1.864, CI = 1.084-3.205) were significant variables per the multivariate Cox regression analysis. (4) Conclusion: TB treatment for most TB patients coinfected with HIV/AIDS was not effective. This study identified that an undetectable viral load at the beginning of the disease, previous use of ART, not using illicit drugs and not having previously taken anti-TB treatment are factors associated with successful TB treatment.

A systematic review and repeatability study on the use of deep learning for classifying and detecting tuberculosis bacilli in microscopic images.

Tuberculosis (TB) is among the leading causes of death worldwide from a single infectious agent. This disease usually affects the lungs (pulmonary TB) and can be cured in most cases with a quick diagnosis and proper treatment. Microscopic sputum smear is widely used to diagnose and manage pulmonary TB. Despite being relatively fast and low cost, it can be exhausting because it depends on manually counting TB bacilli (Mycobacterium tuberculosis) in microscope images. In this context, different Deep Learning (DL) techniques are proposed in the literature to assist in performing smear microscopy. This article presents a systematic review based on the PRISMA procedure, which investigates which DL techniques can contribute to classifying TB bacilli in microscopic images of sputum smears using the Ziehl-Nielsen method. After an extensive search and a careful inclusion/exclusion procedure, 28 papers were selected from a total of 400 papers retrieved from nine databases. Based on these articles, the DL techniques are presented as possible solutions to improve smear microscopy. The main concepts necessary to understand how such techniques are proposed and used are also presented. In addition, replication work is also carried out, verifying reproducibility and comparing different works in the literature. In this review, we look at how DL techniques can be a partner to make sputum smear microscopy faster and more efficient. We also identify some gaps in the literature that can guide which issues can be addressed in other works to contribute to the practical use of these methods in laboratories.

Gravitational effects on fibroblasts' function in relation to wound healing.

The spaceflight environment imposes risks for maintaining a healthy skin function as the observed delayed wound healing can contribute to increased risks of infection. To counteract delayed wound healing in space, a better understanding of the fibroblasts' reaction to altered gravity levels is needed. In this paper, we describe experiments that were carried out at the Large Diameter Centrifuge located in ESA-ESTEC as part of the ESA Academy 2021 Spin Your Thesis! Campaign. We exposed dermal fibroblasts to a set of altered gravity levels, including transitions between simulated microgravity and hypergravity. The addition of the stress hormone cortisol to the cell culture medium was done to account for possible interaction effects of gravity and cortisol exposure. Results show a main impact of cortisol on the secretion of pro-inflammatory cytokines as well as extracellular matrix proteins. Altered gravity mostly induced a delay in cellular migration and changes in mechanosensitive cell structures. Furthermore, 20 × g hypergravity transitions induced changes in nuclear morphology. These findings provide insights into the effect of gravity transitions on the fibroblasts' function related to wound healing, which may be useful for the development of countermeasures.

The Effects of Combined Exposure to Simulated Microgravity, Ionizing Radiation, and Cortisol on the In Vitro Wound Healing Process.

Human spaceflight is associated with several health-related issues as a result of long-term exposure to microgravity, ionizing radiation, and higher levels of psychological stress. Frequent reported skin problems in space include rashes, itches, and a delayed wound healing. Access to space is restricted by financial and logistical issues; as a consequence, experimental sample sizes are often small, which limits the generalization of the results. Earth-based simulation models can be used to investigate cellular responses as a result of exposure to certain spaceflight stressors. Here, we describe the development of an in vitro model of the simulated spaceflight environment, which we used to investigate the combined effect of simulated microgravity using the random positioning machine (RPM), ionizing radiation, and stress hormones on the wound-healing capacity of human dermal fibroblasts. Fibroblasts were exposed to cortisol, after which they were irradiated with different radiation qualities (including X-rays, protons, carbon ions, and iron ions) followed by exposure to simulated microgravity using a random positioning machine (RPM). Data related to the inflammatory, proliferation, and remodeling phase of wound healing has been collected. Results show that spaceflight stressors can interfere with the wound healing process at any phase. Moreover, several interactions between the different spaceflight stressors were found. This highlights the complexity that needs to be taken into account when studying the effect of spaceflight stressors on certain biological processes and for the aim of countermeasures development.

Nontuberculous mycobacteria in patients of a specialty hospital.

The incidence and clinical characteristics of NTM diseases in Brazil remain relatively unknown. The present study describes the diagnosis of NTM isolates, the clinical presentation and treatment outcomes. We analyzed NTM isolates in patients of a tertiary hospital in the Southeast region of Brazil, from January 2008 to July 2019. The ATS/IDSA criteria for diagnosis and treatment of these patients was applied. Mycobacterium kansasii were identified in 13/113 (11.5%) patients. In 59/113 (52.2%) patients who met the ATS criteria for disease, 29/59 (49.1%) received treatment, and 22/29 (75.8%) were cured. The major species identified was M. kansasii. The most frequent symptoms among the treated patients were dyspnea and cough, and the proportion of cured patients was high.

Positive tuberculin test and risk of infection by Mycobacterium tuberculosis in a tuberculosis clinic settled in an upright building, in Minas Gerais, Brazil.

BACKGROUND: Occupational Tuberculosis (TB) can lead to work absenteeism and a negative professional impact. Knowing the reactivity of the tuberculin test and the risk of M. tuberculosis infection among healthcare professionals is essential for the revision and reinforcement of control measures against TB transmission. AIM: To assess the reactivity of tuberculin test and risk of M. tuberculosis infection among healthcare professionals working in an upright building, in which a TB Reference Clinic is placed. SUBJECTS AND METHODS: A tuberculosis Skin Test (TST) was done to 251 staff members of a TB clinic that did not have a previous history or suspicion of TB and that did not have a previous TST done. Among subjects with absence of reaction, repeated tests were carried out to assess booster reaction. RESULTS: Fifty one percent of studied subjects (129) had a positive tuberculin test. The booster phenomenon was evidenced in 35.7% (68/190). The seroconversion among non-reactive subjects, subjected to a new TST after one year, was 5.1%. The infection risk was 1.4. CONCLUSIONS: This study indicates an important occupational risk of infection in healthcare settings exposed to high TB incidence, and should be used to better allocate resources for infection control.