Longitudinal characterization of gut microbiota in healthy Bangladeshi infants showed broadly conserved three-staged maturation dynamics compared to Western populations but with population-specific microbial differences, transient illness-associated disruptions, and detectable shifts in key taxa coinciding with the COVID-19 pandemic.
Infant gut microbiota development in urban Bangladesh followed a three-staged successional pattern with progressive increase in diversity across the first 2 years of life.
Comparative analysis with a Belgian infant cohort revealed broadly conserved maturation dynamics but population-specific differences in core bacteria.
High abundances of Segatella were associated with disease in the Bangladeshi infant cohort.
Episodes of illness were associated with transient disruptions in gut microbiota maturation.
The onset of the COVID-19 pandemic coincided with detectable differences in the relative abundance of several key gut microbiota taxa in the second year of the cohort.
Sociocultural and environmental factors, including global disruptions, were identified as important shapers of early-life microbial ecosystems.
This research suggests that the way a baby's gut microbiome develops in the first two years of life follows a similar three-stage pattern across very different parts of the world — in this case, comparing urban Bangladesh to Belgium. Despite this shared developmental roadmap, the specific bacteria present at each stage differed meaningfully between populations. For example, Bangladeshi infants commonly harbored a bacterium called Segatella that was largely absent in Belgian infants, and interestingly, high levels of Segatella were linked to illness episodes in the Bangladeshi children, though its exact role in infant gut health is not yet understood. The study also found that when infants got sick, their gut microbiome development was temporarily thrown off track, though it appeared to recover. Perhaps most strikingly, the second year of data collection overlapped with the start of the COVID-19 pandemic, and the researchers detected measurable changes in the relative amounts of several important gut bacteria during that period — suggesting that large-scale societal disruptions can leave a detectable mark on infant gut development. This research matters because most of what scientists know about infant gut microbiome development comes from studies in Western, high-income countries. This study shows that while the developmental pattern may be broadly similar worldwide, the specific microbial communities involved are shaped by geography, culture, environment, and even global events like a pandemic. This points to the importance of studying diverse populations when trying to define what a 'healthy' infant gut microbiome looks like.
Papadaki M, Falony G, Vieira-Silva S, Tito R, Rymenans L, Swinnen J, et al.. (2026). Global and local trajectories of infant gut microbiota development in Bangladesh across the COVID-19 pandemic.. mSystems. https://doi.org/10.1128/msystems.00101-26