Diet changes due to urbanization in South Africa are linked to microbiome and metabolome signatures of Westernization and colorectal cancer

Transition from traditional high-fiber to Western diets in urbanizing communities of Sub-Saharan Africa is associated with increased risk of non-communicable diseases (NCD), exemplified by colorectal cancer (CRC) risk. To investigate how urbanization gives rise to microbial patterns that may be amenable by dietary intervention, we analyzed diet intake, fecal 16 S bacteriome, virome, and metabolome in a cross-sectional study in healthy rural and urban Xhosa people (South Africa). Urban Xhosa individuals had higher intakes of energy (urban: 3,578 ± 455; rural: 2,185 ± 179 kcal/d), fat and animal protein. This was associated with lower fecal bacteriome diversity and a shift from genera favoring degradation of complex carbohydrates (e.g., Prevotella) to taxa previously shown to be associated with bile acid metabolism and CRC. Urban Xhosa individuals had higher fecal levels of deoxycholic acid, shown to be associated with higher CRC risk, but similar short-chain fatty acid concentrations compared with rural individuals. Fecal virome composition was associated with distinct gut bacterial communities across urbanization, characterized by different dominant host bacteria (urban: Bacteriodota; rural: unassigned taxa) and variable correlation with fecal metabolites and dietary nutrients. Food and skin microbiota samples showed compositional differences along the urbanization gradient. Rural-urban dietary transition in South Africa is linked to major changes in the gut microbiome and metabolome. Further studies are needed to prove cause and identify whether restoration of specific components of the traditional diet will arrest the accelerating rise in NCDs in Sub-Saharan Africa.

Treating drug-resistant tuberculosis in an era of shorter regimens: Insights from rural South Africa

BACKGROUND

Progressive interventions have recently improved programmatic outcomes in drug-resistant tuberculosis (DR-TB) care in South Africa (SA). Amidst these, a shorter regimen was introduced in 2017 with weak evidence, and has shown mixed results. Outcomes still fall short of national targets, and the coronavirus disease 2019 pandemic has undermined progress to date.

OBJECTIVES

To describe the outcomes of participants treated for DR-TB using a shorter, compared with a longer, regimen in a deeply rural SA setting, and to explore other factors affecting these outcomes.

METHODS

This retrospective cohort study describes outcomes in short and long DR-TB treatment regimens, over 5 years, at two rural treatment sites in SA. Characteristics were analysed for outcome correlates using multivariable logistic regression models.

RESULTS

Of 282 treatment episodes, 62% were successful, with higher success in shorter (69%) compared with longer regimens (58%). Mortality was approximately 21% in both groups. Characteristics included high proportions of HIV co-infection (61%). Injectables (adjusted odds ratio (aOR) 3.00, 95% confidence interval (CI) 1.48 - 6.09), bedaquiline (aOR 3.16, 95% CI 1.36 - 7.35), increasing age (aOR 0.97, 95% CI 0.95 - 0.99) and HIV viraemia defined as final HIV-RNA viral load >1 000 copies/mL (aOR 0.16, 95% CI 0.07 - 0.37) were all significantly and independently associated with treatment success. Injectables (aOR 0.22, 95% CI 0.08 - 0.57), bedaquiline (aOR 0.05, 95% CI 0.01 - 0.19), increasing age (aOR 1.09, 95% CI 1.05 - 1.13), extra-pulmonary TB (aOR 8.15, 95% CI 1.62 - 41.03) and HIV viraemia (aOR 9.20, 95% CI 3.22 - 26.24) were all significantly and independently associated with mortality.

CONCLUSION

In a rural context, treating DR-TB amid limited resources and a high burden of HIV co-infection, we found that after considering controls, a short regimen was no different to a longer regimen in terms of success or mortality. Therefore, by alleviating burdens on multiple stakeholders, a short regimen is likely to be favourable for rural patients, clinicians, and healthcare systems. Besides other previously described correlates of outcomes, HIV viraemia emerged as a novel marker for reliably predicting poor outcomes in DR-TB with HIV co-infection, and a pragmatic target for intervention.

TB prevention cascade at a district hospital in rural Eastern Cape, South Africa

SETTING

Rural Eastern Cape, South Africa.

OBJECTIVE

To identify steps in the TB preventive care cascade from routinely collected data among TB patients at a district hospital prior to the implementation of a novel TB program.

DESIGN

This was a retrospective study. We adapted the TB prevention cascade to measure indicators routinely collected at district hospitals for TB using a cascade framework to evaluate outcomes in the cohort of close contacts.

RESULTS

A total of 1,722 charts of TB patients were reviewed. The majority of patients (87%) were newly diagnosed with no previous episodes of TB. A total of 1,548 (90%) patients identified at least one close contact. A total of 7,548 contacts were identified with a median of 4.9 (range 1-16) contacts per patient. Among all contacts identified, 2,913 (39%) were screened for TB. Only 15 (0.5%) started TB preventive therapy and 122 (4.4%) started TB treatment. Nearly 25% of all medical history and clinical information was left unanswered among the 1,722 TB charts reviewed.

CONCLUSION

Few close contacts were screened or started on TB preventive therapy in this cohort. Primary care providers for TB care in district health facilities should be informed of best practices for screening and treating TB infection and disease.

Effects of an auditory model on the learning of relative and absolute timing

The effects of an auditory model on the learning of relative and absolute timing were examined. In 2 experiments, participants attempted to learn to produce a 1,000- or 1,600-ms sequence of 5 key presses with a specific relative-timing pattern. In each experiment, participants were, or were not, provided an auditory model that consisted of a series of tones that were temporally spaced according to the criterion relative-timing pattern. In Experiment 1, participants (n = 14) given the auditory template exhibited better relative- and absolute-timing performance than participants (n = 14) not given the auditory template. In Experiment 2, auditory and no-auditory template groups again were tested, but in that experiment each physical practice participant (n = 16) was paired during acquisition with an observer (n = 16). The observer was privy to all instructions as well as auditory and visual information that was provided the physical practice participant. The results replicated the results of Experiment 1: Relative-timing information was enhanced by the auditory template for both the physical and observation practice participants. Absolute timing was improved only when the auditory model was coupled with physical practice. Consistent with the proposal of D. M. Scully and K. M. Newell (1985), modeled timing information in physical and observational practice benefited the learning of the relative-timing features of the task, but physical practice was required to enhance absolute timing.