Tuberculosis presentation and outcomes in older Hispanic adults from Tamaulipas, Mexico.

Older people are at high risk of developing and dying from pulmonary infections like tuberculosis (TB), but there are few studies among them, particularly in Hispanics. To address these gaps, we sought to identify host factors associated with TB and adverse treatment outcomes in older Hispanics by conducting a cross-sectional study of TB surveillance data from Tamaulipas, Mexico (2006-2013; n = 8381). Multivariable logistic regressions were assessed for older adults (OA ≥65 years) when compared to young (YA, 18-39 years) and middle-aged adults (40-64 years). We found that the OA had features associated with a less complicated TB (e.g., lower prevalence of extra-pulmonary TB and less likely to abandon treatment or have drug resistant TB), and yet, were more likely to die during TB treatment (adj-OR 3.9, 95% 2.5, 5.25). Among the OA, excess alcohol use and low body mass index increased their odds of death during TB treatment, while a higher number of reported contacts (social support) was protective. Diabetes was not associated with adverse outcomes in OA. Although older age is a predictor of death during TB disease, OA are not prioritized by the World Health Organization for latent TB infection screening and treatment during contact investigations. With safer, short-course latent TB infection treatment available, we propose the inclusion of OA as a high-risk group in latent TB management guidelines.

South to North Migration Patterns of Tuberculosis Patients Diagnosed in the Mexican Border with Texas.

The Mexican state of Tamaulipas serves as a migration waypoint into the US. Here, we determined the contribution of immigrants to TB burden in Tamaulipas. TB surveillance data from Tamaulipas (2006-2013) was used to conduct a cross-sectional characterization of TB immigrants (born outside Tamaulipas) and identify their association with TB treatment outcomes. Immigrants comprised 30.8% of TB patients, with > 99% originating from internal Mexican migration. Most migration was from South to North, with cities adjacent to the US border as destinations. Immigrants had higher odds of risk factors for TB [older age (≥ 65 year old, OR 2.4, 95% CI 2.1, 2.8), low education (OR 1.3, 95% CI 1.2, 1.4), diabetes (OR 1.2, 95% CI 1.1, 1.4)], or abandoning treatment (adjusted OR 1.2, 95% CI 1.0, 1.5). There is a need to identify strategies to prevent TB more effectively in Tamaulipas, a Mexican migration waypoint.

Diabetes screen during tuberculosis contact investigations highlights opportunity for new diabetes diagnosis and reveals metabolic differences between ethnic groups.

Type 2 diabetes (T2D) is a prevalent risk factor for tuberculosis (TB), but most studies on TB-T2D have focused on TB patients, been limited to one community, and shown a variable impact of T2D on TB risk or treatment outcomes. We conducted a cross-sectional assessment of sociodemographic and metabolic factors in adult TB contacts with T2D (versus no T2D), from the Texas-Mexico border to study Hispanics, and in Cape Town to study South African Coloured ethnicities. The prevalence of T2D was 30.2% in Texas-Mexico and 17.4% in South Africa, with new diagnosis in 34.4% and 43.9%, respectively. Contacts with T2D differed between ethnicities, with higher smoking, hormonal contraceptive use and cholesterol levels in South Africa, and higher obesity in Texas-Mexico (p < 0.05). PCA analysis revealed striking differences between ethnicities in the relationships between factors defining T2D and dyslipidemias. Our findings suggest that screening for new T2D in adult TB contacts is effective to identify new T2D patients at risk for TB. Furthermore, studies aimed at predicting individual TB risk in T2D patients, should take into account the heterogeneity in dyslipidemias that are likely to modify the estimates of TB risk or adverse treatment outcomes that are generally attributed to T2D alone.

Characterization of the Antigenic Heterogeneity of Lipoarabinomannan, the Major Surface Glycolipid of Mycobacterium tuberculosis, and Complexity of Antibody Specificities toward This Antigen.

Lipoarabinomannan (LAM), the major antigenic glycolipid of Mycobacterium tuberculosis, is an important immunodiagnostic target for detecting tuberculosis (TB) infection in HIV-1-coinfected patients, and is believed to mediate a number of functions that promote infection and disease development. To probe the human humoral response against LAM during TB infection, several novel LAM-specific human mAbs were molecularly cloned from memory B cells isolated from infected patients and grown in vitro. The fine epitope specificities of these Abs, along with those of a panel of previously described murine and phage-derived LAM-specific mAbs, were mapped using binding assays against LAM Ags from several mycobacterial species and a panel of synthetic glycans and glycoconjugates that represented diverse carbohydrate structures present in LAM. Multiple reactivity patterns were seen that differed in their specificity for LAM from different species, as well as in their dependence on arabinofuranoside branching and nature of capping at the nonreducing termini. Competition studies with mAbs and soluble glycans further defined these epitope specificities and guided the design of highly sensitive immunodetection assays capable of detecting LAM in urine of TB patients, even in the absence of HIV-1 coinfection. These results highlighted the complexity of the antigenic structure of LAM and the diversity of the natural Ab response against this target. The information and novel reagents described in this study will allow further optimization of diagnostic assays for LAM and may facilitate the development of potential immunotherapeutic approaches to inhibit the functional activities of specific structural motifs in LAM.

Tuberculosis-diabetes epidemiology in the border and non-border regions of Tamaulipas, Mexico.

Type 2 diabetes mellitus (DM) is a re-emerging risk factor for TB development and adverse TB outcomes. As a follow-up of our previous study in 1998-2004, we reassessed prevalence of DM and its associated factors among 8431 TB patients using surveillance data from 2006 to 2013 for the Mexican state of Tamaulipas, across the border with Texas. Prevalence of DM was 25.2%, with an increase of at least 2.8% over the study period. Newly discovered factors associated with TB-DM (versus no DM) were lower education and higher unemployment (p < 0.001), which are reportedly associated with poorer DM management. At least 15% of the DM patients were newly-diagnosed and younger than those previously diagnosed, showing the importance of early DM diagnosis at TB clinics. TB-DM patients were more likely to have smear-positive, pulmonary (versus extra-pulmonary) and drug-resistant TB (1.9-, 3.8- and 1.4-fold, respectively). During treatment, TB-DM patients were more likely to be smear-positive, and less likely to die or abandon TB treatment. Thus, the increasing prevalence of DM among TB, and its association with low education, features of a more contagious TB, and drug resistance, highlight the need for design of TB management programs in DM patients, blood testing of all new TB patients for DM, and if positive for DM, testing for drug resistance.