Fecal biomarkers of environmental enteric dysfunction and the gut microbiota of rural Malawian children: An observational study

David Chaima,Harry Pickering,John D Hart,Sarah E Burr,Kenneth M Maleta,Khumbo Kalua,Robin L Bailey,Martin J Holland

doi:10.1016/j.heliyon.2021.e08194

David Chaima, Harry Pickering + Show 6 more

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https://doi.org/10.1016/j.heliyon.2021.e08194

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Abstract

Environmental enteric dysfunction (EED) is a subclinical condition of the gut characterized by changes in morphology and function with underlying chronic inflammatory responses. This study characterized composition and diversity of the gut microbiota in rural Malawian children with and without signs of EED. Fecal samples were collected from children aged 1–59 months. Neopterin, myeloperoxidase and alpha-1 antitrypsin concentrations were quantified by ELISA and combined to form a composite EED score using principal component analysis. DNA was extracted from fecal samples and V4-16S rRNA gene sequencing was used to characterize the gut microbiota. The concentrations of all three biomarkers decreased with increasing age, which is consistent with other studies of children living in similar low-income settings. Firmicutes, Bacteroidetes, Proteobacteria and Actinobacteria were the dominant phyla while Faecalibacterium and Bifidobacterium were the most prevalent genera. Increased alpha diversity was associated with a reduction in neopterin concentration. Microbiota composition was different between fecal samples with low and high composite EED scores; increased abundance of Succinivibrio was associated with reduced composite EED scores.

Highlights

The gut microbiota is essential in maintaining normal physiological and metabolic processes
We used fecal samples collected from rural Malawian children to characterize the fecal microbiota defined by V4 16S rRNA gene sequencing and explored associations with enteric dysfunction (EED) indicated by fecal levels of MPO, alpha-1 antitrypsin (AAT) and NEO
We estimated the magnitude of intestinal inflammation and permeability in rural Malawian children using fecal biomarkers and explored associations with the fecal microbiota, characterized by 16S rRNA gene sequencing

Summary

Introduction

The gut microbiota is essential in maintaining normal physiological and metabolic processes. A multi-site, longitudinal study by Kosek et al [13] combined the absolute measured concentrations of AAT, MPO and NEO into a single metric, using principal component analysis, to form a composite EED score. They explored the relationship between the composite EED score and linear growth in infants from resource limited settings. We used fecal samples collected from rural Malawian children to characterize the fecal microbiota defined by V4 16S rRNA gene sequencing and explored associations with EED indicated by fecal levels of MPO, AAT and NEO

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