Search

Rationale: Contacts of patients with tuberculosis (TB) constitute an important target population for preventive measures because they are at high risk of infection with Mycobacterium tuberculosis and progression to disease.Objectives: We investigated biosignatures with predictive ability for incident TB.Methods: In a case-control study nested within the Grand Challenges 6-74 longitudinal HIV-negative African cohort of exposed household contacts, we employed RNA sequencing, PCR, and the pair ratio algorithm in a training/test set approach. Overall, 79 progressors who developed TB between 3 and 24 months after diagnosis of index case and 328 matched nonprogressors who remained healthy during 24 months of follow-up were investigated.Measurements and Main Results: A four-transcript signature derived from samples in a South African and Gambian training set predicted progression up to two years before onset of disease in blinded test set samples from South Africa, the Gambia, and Ethiopia with little population-associated variability, and it was also validated in an external cohort of South African adolescents with latent M. tuberculosis infection. By contrast, published diagnostic or prognostic TB signatures were predicted in samples from some but not all three countries, indicating site-specific variability. Post hoc meta-analysis identified a single gene pair, C1QC/TRAV27 (complement C1q C-chain / T-cell receptor-α variable gene 27) that would consistently predict TB progression in household contacts from multiple African sites but not in infected adolescents without known recent exposure events.Conclusions: Collectively, we developed a simple whole blood-based PCR test to predict TB in recently exposed household contacts from diverse African populations. This test has potential for implementation in national TB contact investigation programs.

Tuberculosis (TB), caused by the human pathogen Mycobacterium tuberculosis, is a recognized disease in human-managed and wild Asian elephants (Elephas maximus) and African elephants (Loxodonta africana) (1-3). Previous findings demonstrate [...]

Background Diabetes mellitus (DM) patients are three times more likely to develop tuberculosis (TB) than the general population. Active TB screening in people with DM is part of a bidirectional approach. The aim of this study was to conduct pragmatic active TB screening among DM patients in four countries to inform policy. Methods DM patients were recruited in Indonesia (n=809), Peru (n=600), Romania (n=603) and South Africa (n=51). TB cases were diagnosed using an algorithm including clinical symptoms and chest X-ray. Presumptive TB patients were examined with sputum smear and culture. Results A total of 171 (8.3%) individuals reported ever having had TB (South Africa, 26%; Indonesia, 12%; Peru, 7%; Romania, 4%), 15 of whom were already on TB treatment. Overall, 14 (0.73% [95% confidence interval 0.40 to 1.23]) TB cases were identified from screening. Poor glucose control, smoking, lower body mass index, education and socio-economic status were associated with newly diagnosed/current TB. Thirteen of the 14 TB cases diagnosed from this screening would have been found using a symptom-based approach. Conclusions These data support the World Health Organization recommendation for routine symptom-based screening for TB in known DM patients in high TB-burden countries. DM patients with any symptoms consistent with TB should be investigated and diagnostic tools should be easily accessible. [ABSTRACT FROM AUTHOR]

Background People with diabetes have an increased risk of developing active tuberculosis (TB) and are more likely to have poor TB-treatment outcomes, which may impact on control of TB as the prevalence of diabetes is increasing worldwide. Blood transcriptomes are altered in patients with active TB relative to healthy individuals. The effects of diabetes and intermediate hyperglycemia (IH) on this transcriptomic signature were investigated to enhance understanding of immunological susceptibility in diabetes-TB comorbidity. Methods Whole blood samples were collected from active TB patients with diabetes (glycated hemoglobin [HbA1c] ≥6.5%) or IH (HbA1c = 5.7% to <6.5%), TB-only patients, and healthy controls in 4 countries: South Africa, Romania, Indonesia, and Peru. Differential blood gene expression was determined by RNA-seq (n = 249). Results Diabetes increased the magnitude of gene expression change in the host transcriptome in TB, notably showing an increase in genes associated with innate inflammatory and decrease in adaptive immune responses. Strikingly, patients with IH and TB exhibited blood transcriptomes much more similar to patients with diabetes-TB than to patients with only TB. Both diabetes-TB and IH-TB patients had a decreased type I interferon response relative to TB-only patients. Conclusions Comorbidity in individuals with both TB and diabetes is associated with altered transcriptomes, with an expected enhanced inflammation in the presence of both conditions, but also reduced type I interferon responses in comorbid patients, suggesting an unexpected uncoupling of the TB transcriptome phenotype. These immunological dysfunctions are also present in individuals with IH, showing that altered immunity to TB may also be present in this group. The TB disease outcomes in individuals with IH diagnosed with TB should be investigated further. [ABSTRACT FROM AUTHOR]

Background Diabetes mellitus (DM) increases active tuberculosis (TB) risk and worsens TB outcomes, jeopardizing TB control especially in TB-endemic countries with rising DM prevalence rates. We assessed DM status and clinical correlates in TB patients across settings in Indonesia, Peru, Romania, and South Africa. Methods Age-adjusted DM prevalence was estimated using laboratory glycated hemoglobin (HbA1c) or fasting plasma glucose in TB patients. Detailed and standardized sociodemographic, anthropometric, and clinical measurements were made. Characteristics of TB patients with or without DM were compared using multilevel mixed-effect regression models with robust standard errors. Results Of 2185 TB patients (median age 36.6 years, 61.2% male, 3.8% human immunodeficiency virus–infected), 12.5% (267/2128) had DM, one third of whom were newly diagnosed. Age-standardized DM prevalence ranged from 10.9% (South Africa) to 19.7% (Indonesia). Median HbA1c in TB–DM patients ranged from 7.4% (Romania) to 11.3% (Indonesia). Compared to those without DM, TB–DM patients were older and had a higher body mass index (BMI) (P value <.05). Compared to those with newly diagnosed DM, TB patients with diagnosed DM had higher BMI and HbA1c, less severe TB, and more frequent comorbidities, DM complications, and hypertension (P value <.05). Conclusions We show that DM prevalence and clinical characteristics of TB–DM vary across settings. Diabetes is primarily known but untreated, hyperglycemia is often severe, and many patients with TB–DM have significant cardiovascular disease risk and severe TB. This underlines the need to improve strategies for better clinical management of combined TB and DM. [ABSTRACT FROM AUTHOR]

Copyright of Tropical Medicine & International Health is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)