Risk Factors For Tuberculosis Infection Research Articles

Occurence and risk factors of tuberculosis infection in orphanage children in Bali

Background Tuberculosis (TB) is an infectious disease that is still a common threat worldwide, especially in pediatric populations. TB transmission occurs particularly when the transmitter has no obvious manifestation of the disease. There is a higher incidence of TB infection in children than in the general population, especially in high risk populations such as children in orphanages. However, the incidence of TB infection in orphaned children in Indonesia, including Bali, is unknown. Objective To describe the incidence and risk factors for TB infection in children in orphanages in Bali. Methods This case-control study was conducted in 12 orphanages in Bali. Subjects were divided into a case group comprised of children with TB infection, and a control group comprised of those without TB infection. TB infection was diagnosed by positive tuberculin test without clinically confirmed TB. Results A total of 175 children were recruited as subjects. There were 49 (28.0%) children with TB infection. Bivariate analysis revealed significant associations between density, humidity, ventilation/room area ratio, and area of ??origin with TB infection. Multivariate analysis showed that ventilation/room area ratio and room humidity of ?73% were independently positive correlated with TB infection. Natural lighting and BCG scar were not significantly different between groups. Conclusion The occurence of TB infection in children residing in orphanages in Bali is high (28%). The risk factors identified independently are lower ventilation and higher room humidity.

Nutritional status in patients with tuberculosis and diabetes mellitus: A comparative observational study

BackgroundIndia has been estimated to have 14 % of malnourished population and a high TB incidence burden with a 26.9 lakh cases. Malnutrition and diabetes mellitus are major risk factors for tuberculosis infection. Malnutrition in patients with both tuberculosis and diabetes (TB-DM) population worsens the disease severity, treatment outcomes and increases morbidity and mortality risk. ObjectiveTo assess the nutritional status in patients with TB-DM compared with patients with TB and DM alone. MethodRecords from January 2016 to November 2020 for patients admitted to Kasturba Hospital, Manipal were assessed. Data pertaining to glycemic parameters, nutritional parameters, and other relevant laboratory parameters were extracted for assessment. The study population were divided into three groups i.e. patients with TB-DM, TB and DM. The statistical association was carried out with one-way ANOVA method, considering p < 0.05 as statistically significant. ResultsA total of 291 patients were included, with 97 patients in each group; among those, male and female were 86.27 % and 13.73 % respectively. Cardiovascular co-morbidity was predominant in the DM (68.04 %) and TB-DM (26.8 %) group. The mean value of HbA1c (10.47 %) was found to be highest for the TB-DM group. Low levels of albumin were reported by 71.91 % of patients of the TB group, whereas 73.68 % patients in TB-DM group had vitamin D deficiency. Moreover, higher prevalence of low MCV and MCH in the TB-DM group suggest an increased risk of iron-deficiency anemia. ConclusionThe findings of our study reflect the need for implementation of nutritional support in patients with TB-DM.

Area-Based Sociodemographic Factors Associated with Latent Tuberculosis Infection in a Low-Prevalence Setting.

Area-based sociodemographic markers, such as census tract foreign-born population, have been used to identify individuals and communities with a high risk for tuberculosis (TB) infection in the United States. However, these markers have not been evaluated as independent risk factors for TB infection in children. We evaluated associations between census tract poverty, crowding, foreign-born population, and the CDC's Social Vulnerability Index (CDC-SVI) ranking and TB infection in a population of children tested for TB infection in Boston, Massachusetts. After adjustment for age, crowding, and foreign-born percentage, increasing census tract poverty was associated with increased odds of TB infection (adjusted odds ratio [aOR] per 10% increase in population proportion living in poverty: 1.20 [95% CI, 1.04-1.40]; P = 0.01), although this association was attenuated after further adjustment for preferred language. In separate models, increasing CDC-SVI ranking was associated with increased odds of TB infection, including after adjustment for age and language preference (aOR per 10-point increase in CDC-SVI rank: 1.08 [95% CI, 1.02-1.15]; P = 0.01). Our findings suggest area-based sociodemographic factors may be valuable for characterizing TB infection risk and defining the social ecology of pediatric TB infection in low-burden settings.

The association of IL-17A rs2275913 single nucleotide polymorphism with anti-tuberculous drug resistance in patients with pulmonary tuberculosis

BackgroundDrug-resistant Tuberculosis (DR-TB) is a global health burden with high morbidity and mortality in developing countries including Egypt. The susceptibility to infection with DR-TB strains may be genetically determined. Several interleukin gene polymorphisms were investigated as risk factors for tuberculosis infection but focusing on their association with DR-TB was limited. Therefore, the objective of this study is to assess the association of IL 17 − 197 G > A (rs2275913) single nucleotide polymorphism (SNP) with susceptibility to DR-TB strains in comparison to drug-sensitive tuberculosis (DS-TB) strains in Egyptian patients with pulmonary TB. This cross-sectional study was conducted on 80 patients with DR-TB strains and 80 with DS-TB strains as a control group. Both age and sex were comparable among the study’s groups. IL-17 − 197 G > A (rs2275913) SNP was genotyped by real-time PCR, and IL-17 serum concentration was measured by enzyme-linked immunosorbent assay (ELISA). ResultsThe GA and AA genotype frequencies of IL 17 − 197 G > A (rs2275913) SNP were significantly higher in patients with DR-TB strains than those with DS-TB strains (p < 0.001). The frequency of the A allele was significantly (p < 0.001) higher in patients with DR-TB group (32.5%) compared to the control group (13.8%). Substantial higher serum levels of IL-17 were detected in the DR-TB group with significant association with AA and AG genotypes. ConclusionPolymorphism in IL-17 -197 G > A (rs2275913) resulted in higher serum levels of IL-17 and Egyptian patients with such polymorphism are three times at risk of infection with DR-TB strains than patients with wild type.

IFN-gene polymorphisms as a risk factor for tuberculosis infection in Asian populations: A meta-analysis.

The purpose of this meta-analysis is to verify that rs1861494 and rs2069718, two polymorphisms in the IFN-gene, are associated with tuberculosis (TB) infection in Asian populations. To find appropriate case-control studies, a search was done from the databases, including Google Scholar, Science Direct, Embase, and PubMed. With the aid of MetaGenyo software, statistical analyses were performed. Case and control studies from the available database were used to investigate the relationship between IFN-γ gene polymorphisms and TB infection risk. The protocol for the present meta-analysis was registered using PROSPERO (ID Number: 443605). Information obtained through examining two different variants of the IFN-γ gene showed associations with recessive, allelic, overdominant, and dominant models. This indicates that the statistical value obtained was found to be statistically significant at P = 0.05. The findings of the IFN-γ rs1861494 gene polymorphisms for allelic, dominant, and overdominant models were statistically significant with P > 0.05, whereas the recessive model exhibited a statistically insignificant value (P = 0.25). The IFN-γ rs2069718 gene polymorphism demonstrated statistically significant value for overdominant, recessive, and allelic models (P > 0.05). However, the dominant model shows a statistically insignificant value P = 0.11. The two genetic variations of the IFN-γ gene polymorphisms (rs1861494 and rs2069718) and their association with TB were confirmed by the meta-analysis conducted. More in-depth research into the molecular basis of the association is necessary, and larger-scale epidemiological studies are needed to confirm these findings.

Tuberculosis in patients using biological disease-modifying antirheumatic drugs

Aim: In rheumatic diseases, the possibility of developing tuberculosis (TB) increases due to both the disease itself and the biological disease-modifying antirheumatic drugs (bDMARDs) used for treatment. In our study, we aimed to investigate the causes and risk factors of TB infection in patients using bDMARDs for rheumatological diseases.Methods: Demographic, radiological, laboratory data, tuberculin skin test (TST) results, duration of disease, and medications used in TB patients were recorded in 531 patients who were using bDMARD with the diagnosis of rheumatologic disease.Results: TB developed in 5 (0.9%) of 531 patients. TB was detected in 10% of the anakinra users, 2.4% of the infliximab users, 1.4% of the certolizumab users, 1.2% of the etanercept users, and 0.9% of the adalimumab users. The mean duration of bDMARD use until TB development was 28 months. All the cases were female, and the mean age was 53.8 years.Conclusion: Our study highlights the importance of routine chest X-ray, cervical-supraclavicular lymphadenopathy (LAP) examination, annual TST follow-up, and symptom questioning in TST-negative or anergic patients using bDMARDs.

Tuberculosis Infection in Children and Adolescents.

The burden of tuberculosis (TB) in children and adolescents remains very significant. Several million children and adolescents are infected with TB each year worldwide following exposure to an infectious TB case and the risk of progression from TB infection to tuberculosis disease is higher in this group compared to adults. This review describes the risk factors for TB infection in children and adolescents. Following TB exposure, the risk of TB infection is determined by a combination of index case characteristics, contact features, and environmental determinants. We also present the recently recommended approaches to diagnose and treat TB infection as well as novel tests for infection. The tests for TB infection have limitations and diagnosis still relies on an indirect immunological assessment of cellular immune response to Mycobacterium tuberculosis antigens using immunodiagnostic testing. It is recommended that TB exposed children and adolescents and those living with HIV receive TB preventive treatment (TPT) to reduce the risk of progression to TB disease. Several TPT regimens of similar effectiveness and safety are now available and recommended by the World Health Organisation.

An Elusive Case of Tuberculous Meningitis in a Young Man With Altered Mental Status

BackgroundTuberculous meningitis (TBM) is a rare, frequently elusive diagnosis, often characterized by vague symptoms and associated with high rates of morbidity and mortality. Case ReportWe present a case of TBM in a young man with a headache and altered mental status. In addition, we provide a brief history of TBM, review the pathophysiology of the disease, discuss clinical and radiologic features, and detail the management of TBM both emergently and throughout our patient's hospital course. Why Should an Emergency Physician Be Aware of This?Our patient's lack of pulmonary symptoms, initially unremarkable head computed tomography, and two prior emergency department evaluations for headache without concerning historical features or physical examination findings collectively highlight the challenges of diagnosing TBM early in its symptom course. We encourage emergency physicians to consider TBM in appropriate patients, particularly those with risk factors for tuberculosis infection.

Predisposing Factors of Tuberculosis Infection in Systemic Lupus Erythematosus Patients: A Single-Center Case-Control Study.

Introduction: Indonesia has the second-highest tuberculosis cases in the world, according to the global WHO tuberculosis report, amounting to approximately 10% of the world's tuberculosis cases. Systemic lupus erythematosus (SLE) patients are at an increased risk for tuberculosis infection. This research aims to analyze the association between corticosteroid pulse dose, corticosteroid cumulative dose, SLE disease duration, Systemic Lupus Erythematosus Disease Activity Index (SLEDAI) score, and lupus nephritis status with the development of tuberculosis in SLE patients.Methods: This research was a matched case-control study to identify risk factors of tuberculosis infection in SLE patients. Data were taken from medical records of Cipto Mangunkusumo National General Hospital, a national tertiary hospital. Inclusion criteria were patients who meet the Systemic Lupus Erythematosus International Collaborating Clinics (SLICC) 2012 criteria of SLE in the period of 2012-2016 or patients who meet the SLICC 2012 SLE criteria and developed tuberculosis between 2012 and 2016. Statistical analyses used were bivariate analysis and correlation analysis. All statistical analyses were conducted using SPSS software (IBM Corp., Armonk, NY). All statistical analyses were defined as statistically significant when the p-value was less than 0.05.Results: A total of 48 SLE patients were included from medical records consisting of 24 SLE patients with tuberculosis infection and controls of 24 SLE patients without tuberculosis infection. In this study, it was observed that the presence of lupus nephritis (p = 0.001), administration of pulse corticosteroids (p = 0.048), high corticosteroid cumulative dose (p = 0.001), and high SLEDAI score (p = 0.003) were associated with tuberculosis infection. Correlation analysis showed that all of these variables had a weak positive correlation with tuberculosis infection in SLE patients.Conclusion: SLE patients with lupus nephritis, administration of pulse corticosteroids, high cumulative corticosteroid dose, and high SLEDAI score have a higher risk of tuberculosis infection. Clinicians and patients should be aware of these risk factors in SLE patients to prevent tuberculosis infection. Corticosteroid pulse dose should be avoided in SLE patients and if it is needed, tuberculosis prophylaxis may be considered.

Not Only COVID-19: Prevalence and Management of Latent Mycobacterium Tuberculosis Infection in Three Penitentiary Facilities in Southern Italy.

Latent Mycobacterium tuberculosis infection (LTBI) and active tuberculosis in prisoners are higher than the general population and are two public health concerns, especially in low- and middle-income countries. We conducted a cross-sectional study to determine the prevalence and the factors associated with LTBI among the inmate population detained in three Southern Italian penitentiaries. Tuberculin intradermal reaction skin test was performed on the inmates who agreed to participate in the study. In case of positivity, the QuantiFERON-TB test was performed. In those positive to QuantiFERON, chest X-ray films were performed, and treatment initiated. A total of 381 inmates accepted to participate. The prevalence of LTBI was 4.2%. In the analysis, LTBI was associated with no self-reported contact with active tuberculosis patients within the prisons, and 10% of subjects admitted the use of inhaled drugs. No HIV coinfections were found. No cases of active symptomatic tuberculosis were identified during the study period. Our results confirm that incarceration increases the risk of tuberculous infection. Non-EU nationality and a history of drug addiction appear to be major risk factors for tuberculosis infection in the penitentiary setting. Reinforcing tuberculosis control is essential to prevent its transmission in prisons.

1384. Practice Variations in Pre-Hematopoietic Stem Cell Transplantation Infectious Disease Evaluation

BackgroundHematopoietic stem cell transplantation (HCT), and other forms of cellular therapies such as chimeric antigen receptor T cell therapy (CAR-T), while of critical therapeutic value, confers significant, long-term risk of infectious complications. Recipients would benefit from evaluation by infectious disease (ID) specialists. However, amidst many existing guidelines from ID and oncology societies, pre-transplant ID evaluation and management practices vary across US institutions. To better understand these variations and identify targets for standardization, we conducted a survey of ID and oncology providers at transplant centers in the US.MethodsA 38-question, anonymous, voluntary, online survey was distributed via Google Forms to a professional organization e-mail list of ID providers as well as to followers of relevant Twitter accounts. Responses were collected and analyzed.ResultsA total of 51 responses were received, the majority of which (68.6%) came from ID providers. 60.8% of respondents worked at healthcare facilities with over 500 beds. 43 respondents (84.3%) reported that their center performed autologous and allogeneic HCT as well as CAR-T. 56.8% of CAR-T centers use a standardized template, compared to 70.8% of those providing HCT. For allogeneic HCT centers, 8% reported that no ID evaluation is offered; 34% reported that it is offered “sometimes.” Practices varied for treatment of latent tuberculosis infection prior to HCT: 26.5% treat “All the time;” 10.2% treat “Very rarely.” In assessing risk factors, only 63% and 54% identified HIV infection and healthcare occupation, respectively, as epidemiologic risk factors for tuberculosis infection. 59.2% answered that < 10% of patients are screened for Strongyloides. Only 5 respondents reported universal Strongyloides screening prior to transplant. COVID-19 vaccination for family is recommended “Always” by 95.5% of respondents. 25% have offered influenza vaccination to family through the transplant clinic.Table 1 Differences in ID evaluation practices by type of cellular therapy candidate.Table 2 Characteristics of survey respondents.ConclusionPractices around pre-HCT infectious disease evaluation and management are heterogenous among the centers surveyed. The adoption of standardized screening for and management of infectious diseases in this patient population would likely be beneficial.Disclosures All Authors: No reported disclosures

Immunological Aspects of Latent Tuberculosis Infection in Diabetes Mellitus

AbstractThe interaction of diabetes mellitus (DM) with tuberculosis (TB) is currently a health concern. Diabetes mellitus is one of the main risk factors for TB infection to become latent TB and / or progress to active TB. Immune mechanisms contribute to this increased risk. The disruption of the mycobacteria recognition process, phagocyte activity and cellular activity will affect the disruption of cytokine and chemokine production. Hyperglycemia that occurs will result in delayed adaptive immune response resulting in reduced Th1, Th2, and Th17 cells as well as the cytokines produced by these cells that play a role in macrophage activation and TB inflammatory response. Understanding of the immune mechanisms that underlie the sensitivity of DM to TB infection, especially latent TB, will facilitate the implementation of strategies in screening and therapy to deal with the double burden of both diseases. The purpose of this literature study focuses on the relationship of DM with latent TB infection in terms of immunology.

The Risk of Tuberculosis Infection in Non-dialysis Chronic Kidney Disease Patients.

Background: Patients with chronic kidney disease (CKD) receiving maintenance renal replacement therapy are at higher risk of tuberculosis (TB) infection. The risk of TB infection in CKD patients not receiving dialysis is unknown.Aim: We conduct this study to test the hypothesis that TB infection is negatively correlated to renal function.Design: Non-dialysis CKD stage 1–5 patients, admitted in China Medical University Hospital from January of 2003 to May of 2014, were enrolled in this study and were prospectively followed up to the diagnosis of TB, death, loss to follow-up, or December 2014. The risk factors of TB infection were analyzed using competing-risks regression analysis with time-varying covariates. The initiation of dialysis and patients' death were considered as competing events. Patients' estimated glomerular filtration rate (eGFR) and body mass index (BMI) were recorded at enrollment.Results: They were followed-up for a median duration of 1.4 years. Of the 7221 patients, TB infection was identified in 114 patients. Higher eGFR was associated with lower risk of TB infection (P < 0.01). The adjusted subdistribution hazard ratio (aSHR) was 0.82 [95% confidence interval (CI), 0.72 to 0.94] for every 5 ml/min/1.73 m2 increase in eGFR. In addition, higher BMI (p = 0.01) was associated with a lower risk of TB infection and the aSHR was 0.91 (95% CI, 0.85 to 0.98) for every 1 kg/m2 increase in BMI.Conclusion: Renal function and body mass index are independently associated with the risk of tuberculosis infection in patients with chronic kidney disease not receiving dialysis.

Epidemiology of tuberculosis among different occupational groups in Makkah region, Saudi Arabia

Each year in Saudi Arabia, the Hajj season represents one of the world’s most significant annual mass gatherings, attracting high proportion of immigrants from different parts of the world in small crowded areas, posing a risk for Tuberculosis (TB) transmission. There is a high potential for TB contact and infection in the workplace as it is transmitted through the air. Most of the studies in Saudi Arabia assessed the TB infection among health care workers. However, the TB incidence rate among other variant occupational groups was not yet determined. This study was conducted to assess the incidence rate of tuberculosis, and determine the risk factors of TB infection among different occupational groups in the Makkah region, Saudi Arabia 2016. A cross-sectional study was carried out based on the secondary data of the patients registered in the Saudi national tuberculosis control and prevention program in 2016. Data were then organized and analyzed for age, gender, nationality, educational level, average monthly wage, average weekly working hours, and occupation of the patients. Occupations were reclassified according to the Saudi Standard Classification of Occupation (SSCO). A total of 1270 cases were included in this study, 300 (23.6%) of them were workers. The incidence rate of TB among workers in the Makkah region was 9 per 100,000 workers compared to 31 per 100,000 persons among the general population in 2016. The TB incidence rate was the highest among occupation of supporting basic engineering with 13 per 100,000 workers in 2016. The highest incidence rate of TB among occupations of supporting basic engineering could be attributed to close contact with the general population in closed spaces for long periods of time, and low socioeconomic status.

Impact of vitamin D status and cathelicidin antimicrobial peptide on adults with active pulmonary TB globally: A systematic review and meta-analysis.

Tuberculosis remains a global threat and a public health problem that has eluded attempts to eradicate it. Low vitamin D levels have been identified as a risk factor for tuberculosis infection and disease. The human cathelicidin LL-37 has both antimicrobial and immunomodulatory properties and is dependent on vitamin D status. This systematic review attempts to compare vitamin D andLL-37 levels among adult pulmonary tuberculosis patients to non-pulmonary TB individuals between 16-75 years globally and to determine the association between vitamin D and cathelicidin and any contributing factor among the two study groups. We performed a search, through PubMed, HINARI, Google Scholar, EBSCOhost, and databases. A narrative synthesis through evaluation of vitamin D and LL-37 levels, the association of vitamin D and LL-37, and other variables in individual primary studies were performed. A random-effect model was performed and weighted means were pooled at a 95% confidence interval. This protocol is registered under the International Prospective Register of Systematic Reviews (PROSPERO), registration number CRD42019127232. Of the 2507 articles selected12 studies were eligible for the systematic review and of these only nine were included in the meta-analysis for vitamin D levels and six for LL-37 levels. Eight studies were performed in Asia, three in Europe, and only one study in Africa. The mean age of the participants was 37.3±9.9 yrs. We found low vitamin D and high cathelicidin levels among the tuberculosis patients compared to non-tuberculosis individuals to non-tuberculosis. A significant difference was observed in both vitamin D and LL-37 levels among tuberculosis patients and non-tuberculosis individuals (p = < 0.001). This study demonstrated that active pulmonary tuberculosis disease is associated with hypovitaminosis D and elevated circulatory cathelicidin levels with low local LL-37 expression. This confirms that vitamin D status has a protective role against tuberculosis disease.

ОЦЕНКА ПРОГНОСТИЧЕСКОЙ ЦЕННОСТИ ФАКТОРОВ РИСКА РАЗВИТИЯ ТУБЕРКУЛЕЗНОЙ ИНФЕКЦИИ У ДЕТЕЙ

The study aims to assess the prognostic value of risk factors for tuberculosis infection. Material and methods. A total of 310 children with and without tuberculosis infection are prospectively examined. A comparison of the risk factors for the development of tuberculosis, already used in practice, with the results of a specific study, is carried out. Results. The significance of biomedical risk factors for the development of tuberculosis at the stage of latent tuberculosis infection, such as past chickenpox, untimely vaccination, the presence of allergic diseases, respiratory diseases (bronchial asthma), and recurrent episodes of viral respiratory infections, has been established.

Metformin as a potential protective therapy against tuberculosis in patients with diabetes mellitus: A retrospective cohort study in a single teaching hospital.

Aims/IntroductionThe convergence of tuberculosis (TB) and diabetes mellitus (DM) is a new challenge in Asia as a result of the rising prevalence of diabetes mellitus with higher TB infection rates, and also because diabetes mellitus itself enhances TB disease activity and consequently the spread of TB. We aimed to address the risk presented by diabetes mellitus for TB infection.Materials and MethodsPatients with diabetes mellitus were retrospectively recruited. The baseline assessments included age, sex, body mass index, fasting blood glucose, glycated hemoglobin, urine albumin‐to‐creatinine ratio and estimated glomerular filtration rate. TB was determined by meeting the international classification of disease, for TB diagnosis and receiving anti‐TB treatment for at least 2 months.ResultsIn total, 9,750 individuals with diabetes mellitus were recruited. The event rate of TB was 47 (0.48%). Younger age, lower proportion of men, higher fasting blood glucose and glycated hemoglobin values, and better renal function (estimated glomerular filtration rate and urine albumin‐to‐creatinine ratio) were observed in the metformin‐exposed groups. Old age and male sex were associated with higher TB infection risk on multivariate analysis. Metformin users had a significantly lower risk for TB infection, whereas insulin users had a higher risk for TB infection. However, glycemic status had no effect on TB infection risk.ConclusionsThis study provides clinical evidence from a survey of TB in individuals with diabetes mellitus. Old age, male sex and insulin use were risk factors for TB infection. Metformin remains the first choice of treatment for diabetes mellitus and has a potential protective effect against TB infection.

Tuberculosis infection status and risk factors among health workers: an updated systematic review.

Tuberculosis (TB) infection is a common occupational risk for health workers (HWs) and poses a threat to the patients under their care and to other HWs. Hence, the development of a prevention strategy is crucial. We conducted a study to understand the status and risk factors of TB infection among HWs. The existing literature was searched for all published reports from 1 August 2010 to 31 December 2018, related to TB among HWs according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. The inclusion criteria were: (1) study participants working in a health care facility; (2) TB cases diagnosed by medical professionals; (3) original research articles; and (4) English reports in a peer-reviewed journal. We finally included 61 studies from 642 articles searched initially. The TB infection rate in HWs was higher than that of the general population. Based on 39 studies, the prevalence of TB in HWs (tuberculin skin test positive) was 29.94%. In contrast, the global burden of latent TB infection was 23.0% (95% uncertainty interval: 20.4%–26.4%) in 2014. The risk factors of TB among HWs were aging, long duration of employment, nursing professionals, lack of Bacillus Calmette-Guerin vaccination, and low body mass index. HWs have an increased risk for TB infection, which can cause secondary infections in patients or other HWs. An effective prevention strategy must be developed to enable early diagnosis and prompt treatment.

Effects of cigarette smoke on the administration of isoniazid and rifampicin to macrophages infected with Mycobacterium tuberculosis

Background Smoking is a cause behind many diseases, including tuberculosis, and it is a risk factor for tuberculosis infection and mortality. Moreover, smoking is associated with a poor tuberculosis treatment outcome. Objectives In this study, we focus on the effects of cigarette smoke on an infected cell culture treated with anti-tuberculosis drugs. Materials and methods Cytotoxicity on THP-1, J774A.1 and MH-S cell lines and growth of Mycobacterium tuberculosis exposed to a reference or a commercial cigarette was evaluated. THP-1 cell line was exposed to cigarette smoke, infected with Mycobacterium tuberculosis and treated with anti-tuberculosis drugs. Apoptosis and death cell were also tested on M. bovis BCG infected cells. Minimal inhibitory concentrations of anti-tuberculosis drugs were analyzed. Results All cells lines showed viability values higher than 80% when exposed to cigarette smoke extract. However, THP-1 cell line infected with M. bovis BCG and exposed to Marlboro cigarette smoke showed up to a 54% reduction of apoptotic cells than cells unexposed to smoke. M. tuberculosis exposed to Marlboro cigarette smoke for 11 days had an optical density 16% lower than unexposed bacteria. When cells were infected with M. tuberculosis, the intracellular recovery of CFUs showed up to a 0.66 log reduction in cells exposed to cigarette smoke extract because of a potential impairment in the phagocytosis. Macrophages treated with drugs showed up to a 2.55 log reduction in the intracellular load burden compared with non-treated ones. Despite poor treatment outcome on TB smoker patients, minimal inhibitory concentration of rifampicin increased only 2-fold in M. tuberculosis exposed to cigarette smoke. Conclusion Smoking interferes with tuberculosis treatment impairing the immunity of the host.

Long-term efficacy of BCG vaccination in goat herds with a high prevalence of tuberculosis

Vaccination of goats against tuberculosis (TB) has been promoted as an ancillary tool for controlling the disease in infected livestock herds. A three-year trial to assess the efficacy of BCG vaccine was carried out in five goat herds. At the beginning of the trial (month 0), all animals were tested for TB using thee different diagnostic tests. Animals negative to all tests were vaccinated with BCG and all replacement goat kids were also systematically vaccinated throughout the trial. All animals were tested by Interferon-gamma release assay (IGRA) using vaccine compatible reagents at months 6, 12, 24, and 36. The risk factors for TB infection were also evaluated. At the end of the study, four out of five farms showed variable reductions of the initial prevalence (93.5%, 28.5%, 23.2%, and 14.3% respectively), and an overall incidence reduction of 50% was observed in BCG vaccinated goats, although adult vaccinated goats showed higher incidences than vaccinated goat kids. The unvaccinated positive animals remaining in herds and adult BCG vaccinated goats significantly enhanced the risk of infection in vaccinated animals. A systematic vaccination of goats with BCG, together with the removal of positive unvaccinated animals, may contribute to reducing the TB prevalence in goat herds.