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Mycobacterium tuberculosis (Mtb) is still one of the primary pathogens of humans causing tuberculosis (TB) disease. Mtb embraces nine well-defined phylogenetic lineages with biological and geographical disparities. The lineage L4 is the most globally widespread of all lineages and was introduced to America with European colonization. Taking advantage of many genome projects available in public repositories, we undertake an evolutionary and comparative genomic analysis of 522 L4 Latin American Mtb genomes. Initially, we performed careful quality control of public read datasets and applied several thresholds to filter out low-quality data. Using a genome de novo assembly strategy and phylogenomic methods, we spotted novel south American clades that have not been revealed yet. Additionally, we describe genomic deletion profiles of these strains from an evolutionary perspective and report Mycobacterium tuberculosis L4 sublineages signature-like gene deletions, some of the novel. One is a specific deletion of 6.5 kbp that is only present in sublineage 4.1.2.1. This deletion affects a complex group of 10 genes with putative products annotated, among others, as a lipoprotein, transmembrane protein, and toxin/antitoxin system proteins. The second novel deletion spans for 4.9 kbp and specific of a particular clade of the 4.8 sublineage and affects 7 genes. The last novel deletion affects 4 genes, extends for 4.8 kbp., and is specific to some strains within the 4.1.2.1 sublineage that are present in Colombia, Peru and Brasil., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2023 Baena et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

Introduction: The risk of progression to tuberculosis disease is highest within the first year after M. tuberculosis infection (TBI). We hypothesize that people with newly acquired TBI have a unique cytokine/chemokine profile that could be used as a potential biomarker., Methods: We evaluated socio-demographic variables and 18 cytokines/chemokines in plasma samples from a cohort of people deprived of liberty (PDL) in two Colombian prisons: 47 people diagnosed with pulmonary TB, 24 with new TBI, and 47 non-infected individuals. We performed a multinomial regression to identify the immune parameters that differentiate the groups., Results: The concentration of immune parameters changed over time and was affected by the time of incarceration. The concentration of sCD14, IL-18 and IP-10 differed between individuals with new TBI and short and long times of incarceration. Among people with short incarceration, high concentrations of MIP-3α were associated with a higher risk of a new TBI, and higher concentrations of Eotaxin were associated with a lower risk of a new TBI. Higher concentrations of sCD14 and TNF-α were associated with a higher risk of TB disease, and higher concentrations of IL-18 and MCP-1 were associated with a lower risk of TB disease., Conclusions: There were cytokines/chemokines associated with new TBI and TB disease. However, the concentration of immune mediators varies by the time of incarceration among people with new TBI. Further studies should evaluate the changes of these and other cytokines/chemokines over time to understand the immune mechanisms across the spectrum of TB., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Herrera, Keynan, Lopez, Marín, Vélez, McLaren and Rueda.)

Background: Childhood tuberculosis continues to be a major public health problem. Although the visibility of the epidemic in this population group has increased, further research is needed., Objective: To design, implement and evaluate an integrated care strategy for children under five years old who are household contacts of bacteriologically confirmed pulmonary tuberculosis patients in Medellín and the Metropolitan Area., Methods: A quasi-experimental study in which approximately 300 children who are household contacts of bacteriologically confirmed pulmonary tuberculosis patients from Medellín and the Metropolitan Area will be evaluated and recruited over one year. A subgroup of these children, estimated at 85, who require treatment for latent tuberculosis, will receive an integrated care strategy that includes: some modifications of the current standardized scheme in Colombia, with rifampicin treatment daily for four months, follow-up under the project scheme with nursing personnel, general practitioners, specialists, professionals from other disciplines such as social work, psychology, and nutritionist. Additionally, transportation and food assistance will be provided to encourage treatment compliance. This strategy will be compared with isoniazid treatment received by a cohort of children between 2015 and 2018 following the standardized scheme in the country. The study was approved by the CIB Research Ethics Committee and UPB., Clinicaltrials: gov identifier NCT04331262., Discussion: This study is expected to contribute to the development of integrated care strategies for the treatment of latent tuberculosis in children. The results will have a direct impact on the management of childhood tuberculosis contributing to achieving the goals proposed by the World Health Organization's End TB Strategy., Trial Registration: ClinicalTrials.gov identifier NCT04331262 . Implementation of an Integrated Care Strategy for Children Contacts of Patients with Tuberculosis. Registered 2 April 2020., (© 2023. The Author(s).)

Objective: To determine the gene expression profile in individuals with new latent tuberculosis infection (LTBI), and to compare them with people with active tuberculosis (TB) and those exposed to TB but not infected., Design: A prospective cohort study. Recruitment and follow-up were conducted between September 2016 to December 2018. Gene expression and data processing and analysis from April 2019 to April 2021., Setting: Two male Colombian prisons., Participants: 15 new tuberculin skin test (TST) converters (negative TST at baseline that became positive during follow-up), 11 people that continued with a negative TST after two years of follow-up, and 10 people with pulmonary ATB., Main Outcome Measures: Gene expression profile using RNA sequencing from PBMC samples. The differential expression was assessed using the DESeq2 package in Bioconductor. Genes with |logFC| >1.0 and an adjusted p-value < 0.1 were differentially expressed. We analyzed the differences in the enrichment of KEGG pathways in each group using InterMiner., Results: The gene expression was affected by the time of incarceration. We identified group-specific differentially expressed genes between the groups: 289 genes in people with a new LTBI and short incarceration (less than three months of incarceration), 117 in those with LTBI and long incarceration (one or more years of incarceration), 26 in ATB, and 276 in the exposed but non-infected individuals. Four pathways encompassed the largest number of down and up-regulated genes among individuals with LTBI and short incarceration: cytokine signaling, signal transduction, neutrophil degranulation, and innate immune system. In individuals with LTBI and long incarceration, the only enriched pathway within up-regulated genes was Emi1 phosphorylation., Conclusions: Recent infection with MTB is associated with an identifiable RNA pattern related to innate immune system pathways that can be used to prioritize LTBI treatment for those at greatest risk for developing active TB., Competing Interests: The authors have declared that no competing interests exist.

Introduction: There is a global consensus that early diagnosis and treatment of tuberculosis (TB) can accelerate its control and mitigate its consequences. The gradual increase in the TB mortality rate from 2014 to 2018 in Honduras, the reform of the health system in 2014, and the partial implementation of the “End TB” strategy motivated this study., Objective: To analyze barriers to and facilitators of diagnosis and treatment affecting the national TB program coverage using data from 2015 to 2019 and provide tools for the effective implementation of the “End TB” strategy in San Pedro Sula, Honduras., Materials and Methods: This was an explanatory sequential mixed-methods study on smear-positive pulmonary TB patients older than 18 years of age. TB notification sheets and medical records from two primary health care facilities were reviewed. Semistructured interviews were conducted with health care providers, patients, and their families., Results: A total of 74.6% of the cases (297/398) did not receive a timely diagnosis; 62.3% (185/297) were men, 80.8% (240/297) were adults, 53.7% (108/297) had less than high school education, 49.2% (123/297) had some occupation, and 98.2% of participants received timely treatment. Identified barriers included low socioeconomic conditions, lack of coordination between public and private health systems, and boundaries set by gangs. Identified facilitators included good care and attitude of the health care personnel and the availability of medications., Conclusions: The lack of opportunity to diagnose the disease affected the coverage of the national TB program due to cultural and health care barriers.

Introduction: Throughout the world tuberculosis (TB) is the second leading cause of death due to an infectious agent. The World Health Organization promotes Isoniazid Preventive Therapy (IPT) in children under 5 years who are contacts of persons diagnosed with smear-positive pulmonary TB (SPPTB). In 2019, 33% of children identified as contacts received IPT globally, while in the Americas 11 countries reached coverages ≥ 75%, only 35% did so in the Dominican Republic (DR). The aim of this study was to identify barriers and facilitators for IPT administration in children under 5 in the Area IV Directorate of Health of the DR's National District., Methods: Descriptive study, using mixed methods and sequential explanatory approach. We characterized children under 5 years who were contacts of a person with SPPTB. Later, semi-structured interviews and content analysis allowed identification of barriers and facilitators for IPT administration in children who were contacts of a person diagnosed with SPPTB, as perceived by relatives and health system personnel., Results: A total of 238 children were identified as contacts of 174 persons with SPPTB: 36% of these received IPT while no data on IPT administration was found for 11% of them. The proportion of children who had a tuberculin skin test (TST) done was < 20%. However, those who had the test done had a greater opportunity to receive IPT (OR: 8.12, CI 95%: 1.60-41.35). Barriers identified include socioeconomic conditions of children and families, stigma, lack of information in clinical and follow-up records, lack of coordination between public and private providers and lack of coherence within national regulations. Facilitators include home based care of persons with TB and their contacts, transfer of treatment to a health centre near household, isoniazid availability, provision of information by health-workers and economic support for food and transportation., Conclusions: Incomplete data, lack of use of TST to rule out active TB, socioeconomic and cultural conditions, were barriers for IPT administration. Implementation of a person centred approach to care was found to be the main facilitator for IPT uptake. Administration of IPT depends predominantly on modifiable health system factors. This allows rapid identification of strategies to improve IPT administration., (© 2022. The Author(s).)

We aim to describe the role of educational inequalities, for sex and age groups, in adult tuberculosis (TB) mortality in Colombia, 1999-2017. We linked mortality data to data estimation of the national population based on censuses and surveys to obtain primary, secondary, and tertiary adult (25+ years of age) age-standardized mortality rates (ASMR) by educational level. Thus, a population-based study was conducted using national secondary mortality data between 1999 and 2017. Tuberculosis age-standardized mortality rates were calculated separately by educational level, sex, and age groups, using Poisson regression models. Educational relative inequalities in adult mortality were evaluated by calculating the rate ratio, and the relative index of inequality (RII). Trends and joinpoints were evaluated by annual percentage change (APC). We found that, out of the 19,720 TB deaths reported, 69% occurred in men, and 45% in older adults (men and women, aged 65+). Men presented higher TB mortality rates than women (ASMR men = 7.1/100,000 inhabitants, ASMR women = 2.7/100,000 inhabitants). As mortality was consistently higher in the lowest educational level for both sexes and all age groups, inequalities in TB mortality were found to be high (RII = 9.7 and 13.4 among men and women, respectively) and growing at an annual rate of 8% and 1%. High and increasing inequalities, regarding educational level, in TB mortality in Colombia suggest the need to comprehensively address strategies for reducing TB by considering social determinants and including health education strategies throughout the country.

Mycobacterium tuberculosis (Mtb) is a successful pathogen causing tuberculosis (TB) disease in humans. It has been shown, that some circulating strains of Mtb in TB endemic populations, are more virulent and more transmissible than others, which may be related to their evolved adaptations to modulate the host immune responses. Underlying these adaptations to the stressful conditions, different genetic regulatory networks involved sRNAs that are mostly unknown for Mtb. We have previously shown that Mcr11 is one of the main sRNAs that determine transcriptomic differences among the Colombian clinical isolates UT127 and UT205 compared to the laboratory strain H37Rv. We found that the knock-down of mcr11 using CRISPRi has a major impact on phenotypic traits, especially in the clinical isolate UT205. Through the analysis of RNA-seq during the knock-down of mcr11 in UT205, we found a downregulation of genes mainly involved in lipid synthesis, lipid metabolism, ribosomal proteins, transport systems, respiratory and energy systems, membrane and cell wall components, intermediary metabolism, lipoproteins and virulence genes. One of the most interesting genes showing transcriptomic changes is OprA (encoded by the gene rv0516c), which has been involved in the K + regulation. Overall, our data may suggest that one of the prominent roles of the sRNA Mcr11 is to regulate genes that control Mtb growth and osmoregulation., (© 2021. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Background: Tuberculosis represents a public health problem, with extrapulmonary disease occurring in 15% of incident cases annually. Early diagnosis is a challenge due to its paucibacillary nature. Recently, a molecular real-time semi-quantitative assay (GeneXpert Ultra) was developed to overcome limitations of the previous assay version (Xpert MTB/RF)., Objective: The objective of the study was to assess the usefulness of the novel next-generation GeneXpert assay in extrapulmonary samples from different anatomic sites under routine diagnostic conditions at a university medical center., Methods: A total of 519 samples from patients with presumptive diagnosis of extrapulmonary TB were subjected to smear microscopy, culture, and molecular assay. Univariate analyses for demographic and microbiological characteristics were performed. The sensitivity, specificity, and Kappa index with a 95% confidence interval were determined., Results: Molecular assay was positive in 53 samples (10.2%), of which 38 (71.6%) belonged to the "low" and "trace" semi-quantitative categories. The overall sensitivity and specificity were 86.4% (95% confidence intervals [CI]: 74.1-98.8) and 95.6% (95% CI: 93.7-97.6), respectively. Phenotypic drug susceptibility testing for rifampin was 100% concordant., Conclusions: Molecular assay showed significant results when compared to other standard tests, making it a useful tool that could lead in the improvement to a rapid diagnosis of extrapulmonary disease.

Objective: To identify factors associated with active tuberculosis (TB) in patients with systemic lupus erythematosus (SLE)., Methods: We performed a retrospective case-control study in two tertiary care teaching hospitals in Medellín, Colombia. From January 2007 to December 2017, a total of 268 patients with SLE were included. SLE patients with TB (cases) were matched 1:3 with SLE patients without TB (controls) by disease duration and the date of the hospitalization in which the diagnosis of TB was made (index date of cases) to the nearest available rheumatology hospitalization in the matched controls (± 2 years). Conditional univariable and multivariable logistic regression analyses were performed., Results: Sixty-seven cases and 201 controls were assessed. Only pulmonary TB occurred in 46.3%, only extrapulmonary TB in 16.4% and disseminated TB in 37.3% of cases. Multivariable logistic regression analysis showed that lymphopenia (OR, 2.91; 95% CI 1.41-6.03; P = 0.004), 12-month cumulative glucocorticoid dose ≥ 1830 mg (OR, 2.74; 95% CI 1.26-5.98; P = 0.011), and having been treated with ≥ 2 immunosuppressants during the last 12 months (OR, 2.81; 95% CI 1.16-6.82; P = 0.022) were associated with TB after adjusting for age, sex, ethnicity, disease duration, disease activity, and comorbidity index. A trend towards an association of kidney transplantation with TB was also found (OR, 3.77; 95% CI 0.99-14.30; P = 0.051)., Conclusion: Among SLE patients, cumulative glucocorticoid dose, lymphopenia, and the use of ≥ 2 immunosuppressants during the last 12 months were associated with active TB infection. Key Points • Among SLE patients, a cumulative dose of glucocorticoids equivalent to 5 mg/day of prednisone during the last 12 months is independently associated with the development of TB. • The use of two or more immunosuppressants during the last 12 months is also a risk factor for TB infection development is SLE patients. • Lymphopenia is predominant in SLE patients with TB, being especially profound in those with disseminated TB. • Renal transplant recipients with SLE also have an elevated risk of TB.

Monocytes play a critical role during infection with Mycobacterium tuberculosis (Mtb). They are recruited to the lung, where they participate in the control of infection during active tuberculosis (TB). Alternatively, inflammatory monocytes may participate in inflammation or serve as niches for Mtb infection. Monocytes response to infection may vary depending on the particularities of the clinical isolate of Mtb from which they are infected. In this pilot study, we have examined the baseline mRNA profiles of circulating human monocytes from patients with active TB (MoTB) compared with monocytes from healthy individuals (MoCT). Circulating MoTB displayed a pro-inflammatory transcriptome characterized by increased gene expression of genes associated with cytokines, monocytopoiesis, and down-regulation of MHC class II gene expression. In response to in vitro infection with two clinical isolates of the LAM family of Mtb (UT127 and UT205), MoTB displayed an attenuated inflammatory mRNA profile associated with down-regulation the TREM1 signaling pathway. Furthermore, the gene expression signature induced by Mtb UT205 clinical strain was characterized by the enrichment of genes in pathways and biological processes mainly associated with a signature of IFN-inducible genes and the inhibition of cell death mechanisms compared to MoTB-127, which could favor the establishment and survival of Mtb within the monocytes. These results suggest that circulating MoTB have an altered transcriptome that upon infection with Mtb may help to maintain chronic inflammation and infection. Moreover, this functional abnormality of monocytes may also depend on potential differences in virulence of circulating clinical strains of Mtb., (Copyright © 2020 Lavalett, Ortega and Barrera.)

Background: People living in long-term care facilities (LTCF) are at high risk to develop active tuberculosis primarily as a result of reactivation of a latent TB infection, or endemic transmission between residents. Current national guidelines in Canada are to use a posterior-anterior and lateral chest X-ray to screen for TB for those over 65 years old, upon admission to a LTCF. Objective: To assess the available evidence for cost benefits of universal chest X-ray screening for new LTCF residents. Methodology: We conducted a search for all articles published until September 2018, in PubMed and WorlCat databases, in English, using a combination of key words: chest X-ray, chest radiography or CXR, long-term care, elderly, screening, and tuberculosis. We also reviewed publicly available guidelines for screening new residents to LTCF from across Canada. We report on a qualitative synthesis of the evidence in the documents retrieved. Results: The final review yielded four cost-effectiveness studies (2 of 4 conducted in countries with low incidence), one systematic review, one recommendation/editorial, and one cohort study. We found that in a tuberculosis low-incidence country the CXR cost per identified case was $672,298 CAD. Enacting a more targeted screening program, perhaps one that tests only those who previously had TB, or other high-risk medical conditions may enhance the cost-effectiveness. Recommendations: We suggest reviewing the screening policy for active TB in people entering LTCF, which is based on a CXR. The results indicate that a targeted search for active TB in people with symptoms or other high-risk medical conditions may be more cost-effective., (Copyright © 2020 Herrera Diaz, Haworth-Brockman and Keynan.)

The heterogeneity of the clinical outcome of Mycobacterium tuberculosis (Mtb) infection may be due in part to different strategies used by circulating strains to cause disease. This heterogeneity is one of the main limitations to eradicate tuberculosis disease. In this study, we have compared the transcriptional response of two closely related Colombian clinical isolates (UT127 and UT205) of the LAM family under two axenic media conditions. These clinical isolates are phenotypically different at the level of cell death, cytokine production, growth kinetics upon in vitro infection of human tissue macrophages, and membrane vesicle secretion upon culture in synthetic medium. Using RNA-seq, we have identified different pathways that account for two different strategies to cope with the stressful condition of a carbon-poor media such as Sauton's. We showed that the clinical isolate UT205 focus mainly in the activation of virulence systems such as the ESX-1, synthesis of diacyl-trehalose, polyacyl-trehalose, and sulfolipids, while UT127 concentrates its efforts mainly in the survival mode by the activation of the DNA replication, cell division, and lipid biosynthesis. This is an example of two Mtb isolates that belong to the same family and lineage, and even though they have a very similar genome, its transcriptional regulation showed important differences. This results in summary highlight the necessity to reach a better understanding of the heterogeneity in the behavior of these circulating Mtb strains which may help us to design better treatments and vaccines and to identify new targets for drugs.

Setting: Five Colombian cities: Villavicencio, Pereira, Cucuta, Bucaramanga and Bosa., Objective: To describe the knowledge, attitudes and practices related to tuberculosis (TB) in household contacts (HHCs) of TB patients., Methods: A cross-sectional study was conducted. The estimated sample size required was 855. The World Health Organization guide 'Advocacy, communication and social mobilization for TB control: a guide to developing knowledge, attitude and practice surveys' was translated into Spanish and adapted to the dialect of each city. HHCs were invited to participate in the study and included if they agreed., Results: We interviewed 878 HHCs. Most of them knew that TB was transmitted by airborne droplets; however, 52.2% also said that TB could be transferred from one person to another by sharing plates or clothes or shaking hands. Fifty-five per cent of HHCs acquired TB-related information from health care workers, and 44% from family members and friends. Fear was the main reaction reported by HHCs when they were informed of a TB diagnosis (60%). Eighty-five per cent of HHCs answered that the community rejects or avoids TB cases., Conclusion: There are significant gaps in the knowledge about TB and the stigmatisation associated with it. Educational strategies should be designed together with the community to demystify many misconceptions about TB.

Introduction: Tuberculosis (TB) is an important cause of morbidity and mortality in HIV patients. It is unknown if the advent of molecular diagnostic methods and a greater availability of antiretroviral therapy (ART) in our country have changed some characteristics of the TB/HIV co-infection., Objective: To describe the epidemiology, clinical features, diagnosis, resistance patterns, tuberculosis drug effects and mortality in co-infected patients., Materials and Methods: Retrospective study based on the review of medical records of hospitalized co-infected adults in a university hospital in Medellín, Colombia., Results: A total of 178 patients was included in the study. TB and HIV diagnosis was simultaneous in 49.4%. In the moment of TB diagnosis, the median CD4 count was 61 cells/μL (27-145). Pulmonary tuberculosis (PTB) occurred in 28% of patients, extrapulmonary (EPTB) in 23%, and mixed TB in 48.9%. The main EPTB affectations were lymphatic (55.4%), gastrointestinal (35.9%), and of the central nervous system (18.7%). Ziehl-Neelsen stain was positive in 137 patients (77%), mycobacterium culture in 121 (68%), and TB-PCR, in 85 of those patients in whom the test was done. Rifampicin resistance was detected in six cases (4.9%). Transaminases (ALT) increased in half of the patients during TB treatment, but only 10% met liver-toxicity criteria. In-hospital mortality was 11.3%. The single risk factor associated with mortality was CD4 count <50/μL (RR=3.9; 95% CI: 1.36-11.37; p=0.01)., Conclusions: When it occurs as an opportunistic infection, TB usually leads to the diagnosis of advanced HIV disease. If used appropriately, TB diagnosis in these patients can be done by conventional methods. It is always necessary to monitor liver function during TB treatment and to rule out drug resistance.

Tuberculosis (TB) occurs in only 3-10% of Mycobacterium tuberculosis (Mtb) infected individuals, suggesting that natural immunity can contain Mtb infection, although this remains poorly understood. Next to T-cells, a potentially protective role for B-cells and antibodies has emerged recently. However, the Mtb antigens involved remain ill-defined. Here, we investigated in a TB-endemic setting IgG levels against 15 Mtb antigens, representing various phases of Mtb infection and known to be potent human T-cell antigens. IgG levels against ESAT6/CFP10, Rv0440, Rv0867c, Rv1737c, Rv2029c, Rv2215, Rv2389c, Rv3616c and Mtb purified protein derivative (PPD) were higher in TB patients than in endemic and non-endemic controls. The only exception was Rv1733c that was preferentially recognized by antibodies from endemic controls compared to TB patients and non-endemic controls, suggesting a potential correlation with control of TB infection and progression. In patients, IgG levels against Ag85B and Rv2029c correlated with Mtb loads, while immunoglobulins against Rv0440 differed between genders. Our results support the potential role of certain Mtb antigen-(Rv1733c) specific antibodies in the control of TB infection and progression, while other Mtb antigen-specific antibodies correlate with TB disease activity and bacillary loads. The findings for Rv1733c agree with previous T-cell results and have implications for including antibody-mediated immunity in designing new strategies to control TB., (Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Introduction: The mechanisms of mononuclear phagocyte death have been associated with the permissiveness and resistance to mycobacterial replication, but it remains unknown whether or not they help predict the risk of developing TB., Objective: To describe the factors associated with the induction of monocyte mitochondrial and membrane damage in response to PPD as well as determine if this type of damage might predict the susceptibility of developing active tuberculosis in a cohort of household contacts (HHCs) from Medellin, Colombia from 2005 to 2008., Methods: The prospective cohort study contains 2060 HHCs patients with pulmonary tuberculosis who were meticulously followed for two years. A survey of the socio-demographic, clinical, epidemiological factors and blood samples were collected. Mononuclear cell cultures were stimulated with or without PPD and the type of monocyte death was determined by the flow of cytometry, an indicator was also used for its analysis. Logistic regression was adjusted by the Generalized Estimations Equations and the survival was estimated with the Kaplan-Meier and Cox regression. Confidence intervals were used for estimating the association., Results: 1,859 out of 2,060 blood samples of the HHCs patients analyzed showed monocyte death. In response to PPD, 83.4% underwent mitochondrial damage while 50.9% had membrane damage. The membrane damage in response to PPD was higher in children under 4 years (OR: 1.57; (95% CI: 1.1 to 2.4) and the HHCs who slept regularly in the same household has an index case of (OR: 1.54; 95% CI: 1.0 to 2.3). After adjustment by age, comorbidities, nutritional status, proximity to index case and overcrowding, the risk of developing active TB among BCG vaccinated HHCs individuals with induction of mitochondrial damage was HR = 0.19 (95% CI: 0.1 to 0.5)., Conclusions: The induction of monocytes mitochondrial damage by PPD stimulation correlates with protection of TB disease development in BCG-vaccinated HHCs. This represents a potential tool to predict susceptibility of developing active disease in this population.

Histoplasmosis is common among persons living with human immunodeficiency virus/acquired immune deficiency syndrome (PLWHA) in Latin America, but its diagnosis is difficult and often nonspecific. We conducted prospective screening for histoplasmosis among PLWHA with signs or symptoms suggesting progressive disseminated histoplasmosis (PDH) and hospitalized in Hospital La María in Medellín, Colombia. The study's aim was to obtain a clinical and laboratory profile of PLWHA with PDH. During 3 years (May 2008 to August 2011), we identified 89 PLWHA hospitalized with symptoms suggestive of PDH, of whom 45 (51%) had histoplasmosis. We observed tuberculosis (TB) coinfection in a large proportion of patients with PDH (35%), so all analyses were performed adjusting for this coinfection and, alternatively, excluding histoplasmosis patients with TB. Results showed that the patients with PDH were more likely to have Karnofsky score ≤ 30 (prevalence ratio [PR] = 1.98, 95% confidence interval [CI] = 0.97-4.06), liver compromised with hepatomegaly and/or splenomegaly (PR = 1.77, CI = 1.03-3.06) and elevation in serum of alanine aminotransferase and aspartate aminotransferase to values > 40 mU/mL (PR = 2.06, CI = 1.09-3.88 and PR = 1.53, CI = 0.99-2.35, respectively). Using multiple correspondence analyses, we identified in patients with PDH a profile characterized by the presence of constitutional symptoms, namely weight loss and Karnofsky classification ≤ 30, gastrointestinal manifestations with alteration of liver enzymes and hepatosplenomegaly and/or splenomegaly, skin lesions, and hematological alterations. Study of the profiles is no substitute for laboratory diagnostics, but identifying clinical and laboratory indicators of PLWHA with PDH should allow development of strategies for reducing the time to diagnosis and thus mortality caused by Histoplasma capsulatum., (© The American Society of Tropical Medicine and Hygiene.)

Multifunctional T cells have been shown to be protective in chronic viral infections. In mycobacterial infections, however, evidence for a protective role of multifunctional T cells remains inconclusive. Short-term cultures of peripheral blood mononuclear cells stimulated with the Mycobacterium tuberculosis RD1 antigens 6-kDa early secretory antigenic target (ESAT6) and 10-kDa culture filtrate antigen (CFP10), which are induced in the early infection phase, have been mainly used to assess T cell multifunctionality, although long-term culture assays have been proposed to be more sensitive than short-term assays for assessment of memory T cells, which are essential for long-term immunity. Here we used a long-term culture assay system to study the T cell immune responses to the M. tuberculosis latency-associated DosR antigens and reactivation-associated Rpf antigens, compared to ESAT6 and CFP10, in patients with pulmonary tuberculosis (PTB) and household contacts of PTB patients with long-term latent tuberculosis infection (ltLTBI), in a community in which M. tuberculosis is endemic. Our results showed that the DosR antigens Rv1737c (narK2) and Rv2029c (pfkB) and the Rv2389c (rpfD) antigen of M. tuberculosis induced higher frequencies of CD4 + or CD8 + mono- or bifunctional (but not multifunctional) T cells producing interferon gamma (IFN-γ) and/or tumor necrosis alpha (TNF-α) in ltLTBI, compared to PTB. Moreover, the frequencies of CD4 + and/or CD8 + T cells with a CD45RO + CD27 + phenotype were higher in ltLTBI than in PTB. Thus, the immune responses to selected DosR and Rpf antigens may be associated with long-term latency, correlating with protection from M. tuberculosis reactivation in ltLTBI. Further study of the functional and memory phenotypes may contribute to further discrimination between the different states of M. tuberculosis infections., (Copyright © 2016, American Society for Microbiology. All Rights Reserved.)

Background: An incomplete understanding of the immunological mechanisms underlying protection against tuberculosis (TB) hampers the development of new vaccines against TB. We aimed to define host correlates of prospective risk of TB disease following bacille Calmette-Guérin (BCG) vaccination., Methods: In this study, 5,726 infants vaccinated with BCG at birth were enrolled. Host responses in blood collected at 10 weeks of age were compared between infants who developed pulmonary TB disease during 2 years of follow-up (cases) and those who remained healthy (controls)., Results: Comprehensive gene expression and cellular and soluble marker analysis failed to identify a correlate of risk. We showed that distinct host responses after BCG vaccination may be the reason: two major clusters of gene expression, with different myeloid and lymphoid activation and inflammatory patterns, were evident when all infants were examined together. Cases from each cluster demonstrated distinct patterns of gene expression, which were confirmed by cellular assays., Conclusions: Distinct patterns of host responses to Mycobacterium bovis BCG suggest that novel TB vaccines may also elicit distinct patterns of host responses. This diversity should be considered in future TB vaccine development.

Objective: This study sought to determine gender differences in the interpretation of tuberculosis (TB) in a group of patients from the city of Medellín., Methodology: This was a qualitative study, with the grounded theory method. Twelve semistructured interviews were applied to patients from both genders who were cured of TB. The sample was selected through convenience and for analysis the information was categorized through the Atlas Ti tool., Results: Regarding the symptoms, the most reported is cough, but men manifest expectoration more frequently. Men overstated the symptoms, while women tend to minimize them. Women report mental impairment and emotional-type manifestations produced by the disease. Men and women expressed ignorance about the disease upon diagnosis. Both manifested fear of infection, work incapacity, loss of employment, rejection by others, and death. Also highlighted is the importance of family support and of the healthcare personnel. Women expressed shame in that others knew of their disease and mentioned greater intolerance with taking the medications., Conclusion: The gender role constructed culturally constitutes the central axis that explains how men and women interpret TB and can be modified by educational and accompaniment processes. Family support plays an important role in the healing process. Although common aspects exist, delving into the gender differences against the interpretation of TB may permit a different approach of the disease and better control of it.

Introduction: Tuberculosis is a relevant global public health problem. Although reports of the World Health Organization show decrease in overall mortality rates, Colombia and Medellin show no significant decline., Objective: To describe the sociodemographic, clinical, diagnosis, and treatment characteristics of patients who died due to tuberculosis in Medellin, Colombia, during 2012., Materials and Methods: A descriptive study of tuberculosis deaths reported in the city., Results: 93 deaths were identified, of which 32 were confirmed as directly caused by tuberculosis (34.4%); in 23 deaths (24.7%) tuberculosis was an associated cause. Co-morbidities were found in 34 patients (61.7%), HIV being the most common with 18 cases important(32.7%). Social risk factors such as being homeless, drug addiction or having no fixed address were found in 32 cases (58.1%); and there were deficiencies in the healthcare system in 26 cases (47.2%). No meaningful delay in the onset of anti-tuberculosis treatment was found after the microbiological diagnosis; however, 64% of patients did not adhere to treatment., Conclusion: Mortality caused by tuberculosis in Medellin is a relevant problem associated with delays in diagnosis of the disease and lack of adherence to treatment.

Objective: To determine the incidence of pulmonary tuberculosis (TB) in inmates, factors associated with TB, and the time to sputum smear and culture conversion during TB treatment., Methods: Prospective cohort study. All prisoners with respiratory symptoms (RS) of any duration were evaluated. After participants signed consent forms, we collected three spontaneous sputum samples on consecutive days. We performed auramine-rhodamine staining, culturing with the thin-layer agar method, Löwestein-Jensen medium and MGIT, susceptibility testing for first-line drugs; and HIV testing. TB cases were followed, and the times to smear and culture conversion to negative were evaluated., Results: Of 9,507 prisoners held in four prisons between April/30/2010 and April/30/2012, among them 4,463 were screened, 1,305 were evaluated for TB because of the lower RS of any duration, and 72 were diagnosed with TB. The annual incidence was 505 cases/100,000 prisoners. Among TB cases, the median age was 30 years, 25% had <15 days of cough, 12.5% had a history of prior TB, and 40.3% had prior contact with a TB case. TB-HIV coinfection was diagnosed in three cases. History of prior TB, contact with a TB case, and being underweight were risk factors associated with TB. Overweight was a protective factor. Almost a quarter of TB cases were detected only by culture; three cases were isoniazid resistant, and two resistant to streptomycin. The median times to culture conversion was 59 days, and smear conversion was 33., Conclusions: The TB incidence in prisons is 20 times higher than in the general Colombian population. TB should be considered in inmates with lower RS of any duration. Our data demonstrate that patients receiving adequate anti-TB treatment remain infectious for prolonged periods. These findings suggest that current recommendations regarding isolation of prisoners with TB should be reconsidered, and suggest the need for mycobacterial cultures during follow-up.

Introduction: Rheumatoid arthritis patients under treatment with anti-TNF-α are at a high risk of developing active tuberculosis, and therefore, screening for latent tuberculosis infection is recommended before anti-TNF-α therapy., Objective: To compare the tuberculin test and IFNγ production induced by culture filtrate proteins(CFPs) and Mycobacterium tuberculosis-specific CFP-10 antigens in rheumatoid arthritis patients., Materials and Methods: An analytic transversal study was conducted in rheumatoid arthritis patients treated at Hospital Universitario San Vicente Fundación between January and December 2007. IFNγ production in response to CFPs and CFP-10 was measured in the supernatants of whole blood cultures and evaluated for correlations with tuberculin reactivity. The degree of concordance between both tests was also established., Results: Forty-five patients were included, of which 14 (31.1%) had a tuberculin reaction of ≥10 mm of induration, 9 (20%) produced IFNγ in response to CFP-10, and 7 were positive for both tests. The correlation between tests was r=0.53 (IC 95%:0.28-0.72), and the global concordance between tests was80%, with a Kappa coefficient of 0.48 (IC95%:0.20-0.76)., Conclusions: Only two tuberculin (-)/CFP-10+ "anergic" patients were observed. By contrast, six tuberculin +/CFP-10(-) "tuberculin false-positive" patients were observed. These data suggest that the tuberculin test is not an appropriate tool for determining the need for tuberculosis prophylaxis.

Tuberculosis (TB) is one of the most important infectious diseases around the world. Several studies have focused on the identification of correlates of protection against TB. Most of them have concentrated on the study of IFN-γ due to its robust association with protection against TB. However, given the complexity of the immune response elicited after Mtb infection, other cytokines should also be considered. In the present study, we evaluated Th1 and Th17 responses and their association with the protection or development of active disease. Therefore, non infected individuals (nonTBi), latently infected individuals (LTBi) and patients with active TB (ATB) were studied. The evaluation of the number of cytokine producing cells by ELISPOT showed a higher number of IFN-γ-producing cells in ATB patients, but no differences were found regarding the number of IL-17 producing cells among studied groups. The evaluation of IFN-γ, IL-2, TNF-α and IL-17 producing CD4+ and CD8+ T cells at 1 day and 6 days of stimulation with mycobacterial antigens suggests the presence of functional signatures associated with latency or active TB. The results presented herein suggest the possible use of the evaluation of Th1-type cytokines, such as IFN-γ and/or TNF-α, as a correlate of protection against TB; however, these results need to be validated for other groups., (Copyright © 2013 Elsevier Ltd. All rights reserved.)

Phenotypic and functional alterations in Mycobacterium tuberculosis T cell subsets have been reported in patients with active tuberculosis. A better understanding of these alterations will increase the knowledge about immunopathogenesis and also may contribute to the development of new diagnostics and prophylactic strategies. Here, the ex vivo phenotype of CD4(+) and CD8(+) T cells and the frequency and phenotype of gamma interferon (IFN-γ)- and interleukin 17 (IL-17)-producing cells elicited in short-term and long-term cultures following CFP-10 and purified protein derivative (PPD) stimulation were determined in noninfected persons (non-TBi), latently infected persons (LTBi), and patients with active tuberculosis (ATB). Phenotypic characterization of T cells was done based on the expression of CD45RO and CD27. Results show that ATB had a reduced frequency of circulating CD4(+) CD45RO(+) CD27(+) T cells and an increased frequency of CD4(+) CD45RO(-) CD27(+) T cells. ATB also had a higher frequency of circulating IL-17-producing CD4(+) T cells than did LTBi after PPD stimulation, whereas LTBi had more IFN-γ-producing CD4(+) T cells than did non-TBi. The phenotype of IFN-γ-producing cells at 24 h differs from the phenotype of IL-17-producing cells with no differences between LTBi and ATB. At 144 h, IFN-γ- and IL-17-producing cells were mainly CD45RO(+) CD27(+) T cells and they were more frequent in ATB. These results suggest that M. tuberculosis infection induces alterations in T cells which interfere with an adequate specific immune response.

Monocytes from tuberculosis patients exhibit functional and phenotypical alterations compared with healthy controls. To determine whether these discrepancies can be explained by changes in monocyte subsets, the expression of CD14 and CD16 was evaluated in tuberculosis patients and healthy controls; additionally, some markers related to the mononuclear phagocytes maturation, differentiation and function, such as CD1a, CD1c, CD11b, CD11c, CD13, CD33, CD36, CD40, CD64, CD68, CD80, CD83, CD86, HLA-DR, CCR2, CCR5, and non-specific esterases (NSE) were determined in monocyte subsets. Patients had increased percentage of circulating CD14(Hi)CD16(+) and CD14(Lo)CD16(+) monocytes. The percentage of monocytes expressing CD11b, CD36, CD64, CD68, CD80, CD86, CCR2 and NSE was lower in CD14(Hi)CD16(+) and CD14(Lo)CD16(+) cells than in CD14(Hi)CD16(-) monocytes. M. tuberculosis infected CD16(+) monocytes produced more TNF-α and less IL-10 than CD16(-) cells at 6 h post-infection. Isolated CD16(+) monocytes spontaneously underwent apoptosis during differentiation into macrophages; in contrast to CD16(-) monocytes that became differentiated into monocyte-derived macrophages (MDM) with a minimal induction of cell death. In addition, there were more Annexin V and propidium iodide positive monocytes in the CD16(+) subset infected with live M. tuberculosis at 24 h than CD16(-) monocytes. Under the culture conditions established for this study, the monocyte subsets did not differentiate into dendritic cells. These results show that tuberculosis patients have an augmented frequency of CD16(+) circulating monocytes which are more prone to produce TNF-α and to undergo cell death in response to M. tuberculosis infection., (Copyright © 2011 Elsevier Ltd. All rights reserved.)

Regulatory T cells (Tregs) play an essential role in immune homeostasis. In infectious diseases Tregs may inhibit protective responses facilitating pathogen multiplication and dissemination, but they may also limit the inflammatory response diminishing tissue damage. Although there is experimental and clinical evidence that Tregs are induced during Mycobacterium tuberculosis infection, their role in the immunopathogenesis of tuberculosis is still not completely understood. In this study, the phenotype, frequency and activity of circulating Tregs in active and latent tuberculosis were evaluated. Phenotypic analysis showed that Tregs were CD4(+)CD25(high)FOXP3(+)CD45RO(+)CD127(-). High levels of circulating Tregs were found in patients with active pulmonary tuberculosis, compared to individuals with latent infection. Treg activity was evaluated by ELISPOT by determining the effect of CD25(+) cell depletion on the frequency of IFN-gamma and IL-17 producing cells after in vitro stimulation with ESAT-6, CFP-10 and PPD. Treg depletion increased the frequency of IFN-gamma producing cells, without affecting the frequency of IL-17 producing cells, in both active and latent tuberculosis, irrespective of the antigen used. Neutralization of IL-10 did not have any effect on the frequency of IFN-gamma and IL-17 producing cells. Altogether, these results suggest that during active tuberculosis Tregs inhibit protective Th1 responses, but not the proinflammatory Th17 responses, facilitating mycobacterial replication and tissue damage.

Objectives: Household contacts (HHCs) of pulmonary tuberculosis patients are at high risk of Mycobacterium tuberculosis infection and early disease development. Identification of individuals at risk of tuberculosis disease is a desirable goal for tuberculosis control. Interferon-gamma release assays (IGRAs) using specific M. tuberculosis antigens provide an alternative to tuberculin skin testing (TST) for infection detection. Additionally, the levels of IFNgamma produced in response to these antigens may have prognostic value. We estimated the prevalence of M. tuberculosis infection by IGRA and TST in HHCs and their source population (SP), and assessed whether IFNgamma levels in HHCs correlate with tuberculosis development., Methods: A cohort of 2060 HHCs was followed for 2-3 years after exposure to a tuberculosis case. Besides TST, IFNgamma responses to mycobacterial antigens: CFP, CFP-10, HspX and Ag85A were assessed in 7-days whole blood cultures and compared to 766 individuals from the SP in Medellín, Colombia. Isoniazid prophylaxis was not offered to child contacts because Colombian tuberculosis regulations consider it only in children under 5 years, TST positive without BCG vaccination., Results: Using TST 65.9% of HHCs and 42.7% subjects from the SP were positive (OR 2.60, p<0.0001). IFNgamma response to CFP-10, a biomarker of M. tuberculosis infection, tested positive in 66.3% HHCs and 24.3% from the SP (OR = 6.07, p<0.0001). Tuberculosis incidence rate was 7.0/1000 person years. Children <5 years accounted for 21.6% of incident cases. No significant difference was found between positive and negative IFNgamma responders to CFP-10 (HR 1.82 95% CI 0.79-4.20 p = 0.16). However, a significant trend for tuberculosis development amongst high HHC IFNgamma producers was observed (trend Log rank p = 0.007)., Discussion: CFP-10-induced IFNgamma production is useful to establish tuberculosis infection prevalence amongst HHC and identify those at highest risk of disease. The high tuberculosis incidence amongst children supports administration of chemoprophylaxis to child contacts regardless of BCG vaccination.

Introduction: Prophylaxis against tuberculosis has been recognized as important for preventing clinical forms of tuberculosis, mainly in HIV positive patients. However, in countries with high tuberculosis prevalence, prophylaxis application and effectiveness remains controversial., Objective: Effectiveness was established for two prophylaxis regimens -isoniazid treatment for nine months and pirazinamid/rifampin for 60 days., Materials and Methods: Two cohort groups of patients diagnosed with HIV/AIDS were compared. One consisted of 131 volunteer patients, who received one of the two prophylactic regimens -pirazinamid/rifampin or isoniazid. The tuberculosis treatment drugs were self-administered and independent of tuberculin response tests. The second group consisted of 200 patients selected from the records of a HIV/AIDS control program. Follow up for both groups was conducted over a two-year period through clinical records., Results: The 2 groups were similar with respect to clinical and demographic variables. A higher proportion of patients in the control group had CD4 counts <200/ml and viral load >100,000 copies. In the prophylactic group, 8% of patients reported adverse effects due to the drug, and one person had tuberculosis in that group (0.8%). Ten persons in the control group contracted tuberculosis (5%) RR=0.15, 95%CI 0.02-1.18, p=0.07. The prophylaxis protective level was calculated to be 80%, after taking into account CD4, viral load, and effective antiretroviral therapy., Conclusion: The prophylaxis against tuberculosis was effective in HIV positive patients, independently of the immune status, viral load, and highly effective antiretroviral therapy.

Law 100 introduced the Health Sector Reform in Colombia, a model of managed competition. This article addresses the effects of this model in terms of output and outcomes of TB control. Trends in main TB control indicators were analysed using secondary data sources, and 25 interviews were done with key informants from public and private insurers and provider institutions, and from the health directorate level. We found a deterioration in the performance of TB control: a decreasing number of BCG vaccine doses applied, a reduction in case finding and contacts identification, low cure rates and an increasing loss of follow up, which mainly affects poor people. Fragmentation occurred as the atomization and discontinuity of the technical processes took place, there was a lack of coordination, as well as a breakdown between individual and collective interventions, and the health information system began to disintegrate. The introduction of the Managed Competition (MC) in Colombia appeared to have adverse effects on TB control due to the dominance of the economic rationality in the health system and the weak state stewardship. Our recommendations are to restructure the reform's public health component, strengthen the technical capacity in public health of the state, mainly at the local and departmental levels, and to improve the health information system by reorienting its objectives to public health goals.

We describe the changes that have been presented in the tendencies of mortality and hospital discharges by tuberculosis (TB) between 1985-1999, period before and during the implementation of the Health Sector Reform (HSR) in Colombia. For it, we carried out an exploratory descriptive study with analysis of time series of hospital discharges and mortality rates of TB in Colombia. It was found that although starting from 1991 the Series approach stabilized, their tendencies showed a significant descent diminishing both in 30% between 1985 and 1990. The steady trend registered from 1991 to 1999, could be explained by deterioration of the primary care during this period, also due to other complex social processes occurred in Colombia during this decade, which barred the continuing the descent trend in hospital discharges and mortality due to TB previously registered. Due to the study design limitations we cannot establish causal relationships between these trends and the health sector reform in the country; we recommend the improvement the health sector performance about public health problems such as TB in order to avoid unnecessary hospitalizations and deaths due to causes responsive to health sector interventions.

Vaccination with attenuated Mycobacterium bovis BCG has been used as the routine procedure to immunize against tuberculosis. Since the efficacy of BCG vaccination is very controversial, the search for new immunoprophylatic tools against tuberculosis is an area of intense interest. Knowledge of the complete sequence of Mycobacterium tuberculosis (Mtb) H37Rv genome and the application of new immunological, biochemical and genetic technologies has led to a detailed understanding of the transcriptome and proteome of this bacterium. Approximately one-third of the human population is infected with Mtb; however, the bacillus is only detected once the symptoms appear and therefore most of the recent efforts have been devoted to the development of a post-infection vaccine. In theory, this vaccine (1) will give rise to an increase in the long-lasting specific immunity against Mtb, (2) will not have significant adverse effects, and (3) will be affordable for the people in third world countries. The main strategies that have been developed include the subunit vaccines, either as a mixture of relevant immunogenic proteins or DNA constructs, recombinant strains of Mycobacterium bovis BCG and Mtb, designed to secrete immunogenic proteins or with attenuated virulence, respectively, and DNA-based vaccines. The subunit vaccines are delivered either as mixtures of immunogenic proteins and adjuvants, or as naked DNA or by viral vectors in order to induce a potent Th1 response. Most of these vaccines have been tested in several kinds of animal models, but they do not fully reproduce the human pathology. However, the results obtained so far are very encouraging and have led to the development of phase I trials in humans.

The interaction between the macrophage and Mycobacterium tuberculosis is mediated by a variety of macrophage membrane-associated proteins. Complement receptors have been implicated in the adherence of M. tuberculosis to macrophages. In the present work, the adherence and/or ingestion of M. tuberculosis H37Rv to human monocyte-derived macrophages (MDM) from patients with tuberculosis (TB) and healthy controls was measured by microscopical examination, [3H]uracil incorporation, and CFU. The adherence and/or ingestion was enhanced by fresh serum and inhibited by heat inactivation, EDTA treatment, and anti-CR1 and anti-CR3 antibodies. Comparison of MDM from TB patients and healthy controls showed that the former exhibited a significantly decreased capacity to adhere and/or ingest M. tuberculosis, as determined by the number of CFU and 3H incorporation. The expression of CR1 (CD35) and CR3 (CD11b/CD18) on MDM from TB patients and healthy controls, as determined by flow cytometry, did not show significant differences. These results suggest that the lower ingestion of M. tuberculosis by MDM from TB patients is not due to defects in complement receptors, and therefore, there might be other molecules involved in the adherence and/or ingestion process that render MDM from TB patients ingest less mycobacteria than those from healthy controls.