Biology subjects

Sahibdeen, V.

Publications and source records attributed to Sahibdeen, V..

3 recordsLinked to original sources

bioRxiv2026

From Growth Faltering to Recovery: Gut Microbial and Body Composition Signatures of Early Childhood Malnutrition Phenotypes

BackgroundChronic malnutrition in early childhood is a multifactorial condition associated with long-term impairments, yet the physiological and gut microbial pathways underlying differential growth trajectories remain poorly understood. ObjectiveWe aimed to characterize phenotypic growth trajectories and identify the associated gut microbial and body composition signatures in infants during the first year of life. MethodsWe analyzed longitudinal data from birth to 12 months in a South African cohort (Soweto, n=45). Individual linear growth trajectories were modeled using the Jenss-Bayley equation, and children were clustered based on model parameters to identify phenotypic subgroups. Body composition (fat-free mass and fat mass) was measured via deuterium dilution at 6 and 12 months, and gut microbiome development was assessed using 16S rRNA gene amplicons at 4, 6, and 12 months. ResultsWe identified distinct phenotypic subgroups including healthy growth, catch-up growth, and growth faltering, that were obscured at the cohort level. These trajectories diverged most dynamically within the first 6 months of life. Integrated analysis revealed that in the growth faltering cluster, height-for-age and fat-free mass z-scores stabilized between 6 and 12 months, whereas fat mass z-scores (FMZ) declined. This trade-off is consistent with a catabolic state where energy reserves are prioritized for lean tissue and bone growth. Furthermore, at 6 months, the growth faltering cluster was enriched with opportunistic pathobionts (e.g., Paraclostridium). In contrast, the catch-up cluster exhibited a transient enrichment of facultative anaerobes (e.g., Enterobacter), supporting a hypothesis that these oxygen-tolerant taxa may help bridge a transitional microbial state in partially oxygenated or inflamed environments to enable physiological recovery. ConclusionsEarly childhood chronic malnutrition phenotypes in South African infants can be defined by distinct microbial and body composition signatures that diverge within six months of life. Integrated interventions should target both host anabolic state and microbiome transitions to support recovery.

microbiology↗

bioRxiv2020

Short- and long-read metagenomics of South African gut microbiomes reveal a transitional composition and novel taxa

Human gut microbiome research focuses on populations living in high-income countries or on the other end of the spectrum, namely non-urban agriculturalist and hunter-gatherer societies. The scarcity of research between these extremes limits our understanding of how the gut microbiota relates to health and disease in the majority of the worlds population. We present the first study evaluating gut microbiome composition in transitioning South African populations using short- and long-read sequencing. We analyzed stool samples from adult females (age 40 - 72) living in rural Bushbuckridge municipality (n=118) or urban Soweto (n=51) and find that these microbiomes are taxonomically intermediate between those of individuals living in high-income countries and traditional communities. We demonstrate that reference collections are incomplete for characterization of microbiomes of individuals living outside high-income countries, resulting in artificially low species-level beta diversity measurements. To improve reference databases, we generated complete genomes of undescribed taxa, including Treponema, Lentisphaerae, and Succinatimonas species. Our results suggest that the gut microbiome in South African populations do not exist along a simple "western-nonwestern" axis and that these populations contain microbial diversity that remains to be described.

genomics↗

bioRxiv2020

Gut Microbiome Profiling of a Rural and Urban South African Cohort Reveals Biomarkers of a Population in Lifestyle Transition

BackgroundComparisons of traditional hunter-gatherers and pre-agricultural communities in Africa with urban and suburban Western North American and European cohorts have clearly shown that diet, lifestyle and environment are associated with gut microbiome composition. Yet, little is known about the gut microbiome composition of most African adults. South Africa comprises a richly diverse ethnolinguistic population that is experiencing an ongoing epidemiological transition and concurrent spike in the prevalence of obesity, largely attributed to a shift towards more Westernized diets and increasingly inactive lifestyle practices. To better characterize the microbiome of African adults living in more mainstream lifestyle settings and to investigate associations between the microbiome and obesity, we conducted a pilot study in two South African cohorts that are representative of urban and rural populations. The study was designed collaboratively with community leaders. As the rate of overweight and obesity is particularly high in women, we collected single time-point stool samples from 170 HIV-negative women (51 at Soweto; 119 at Bushbuckridge), performed 16S rRNA gene sequencing on these samples and compared the data to concurrently collected anthropometric data. ResultsWe found the overall gut microbiome of our cohorts to be reflective of their ongoing epidemiological transition. Specifically, our results show a relatively higher than expected abundance of Western gut-associated taxa such as Barnesiella and the presence of Bifidobacteria and Bacteroides together with the more traditionally non-Western gut-associated Prevotella, Treponema and Succinivibrio. Interestingly, we observed a relatively higher abundance of the Melainabacteria, Vampirovibrio, a predatory bacterium, in the rural cohort. We also found Prevotella, despite its generally high prevalence relative to all taxa present in the cohort, to be associated with obesity. ConclusionsAltogether, this work identifies putative microbial features associated with host health in a historically understudied community. Furthermore, we note the crucial role of community engagement to the success of a study in an African setting, the importance of more population-specific studies to inform targeted interventions as well as present a basic foundation for future research in this regard.

microbiology↗