Abstract

The prevalence of Foetal Alcohol Spectrum Disorders (FASD) in the Western Cape is up to 31%, significantly higher than the global prevalence of 0.77%. Alcohol consumption alters gut microbial composition and compromises the integrity of the intestinal barrier thereby allowing bacteria to enter the bloodstream, and in doing so, be transported to the foetus. Altered foetal bacterial colonisation may subsequently alter infant gut microbiota functioning resulting in increased risk of developing a neurodevelopmental disorder. This study therefore aimed to compare the gut microbial composition of both women who birthed infants diagnosed with and without FASD and that of infants diagnosed with and without FASD.

16S sequencing was performed on microbial DNA extracted from 207 maternal stool samples and 211 infant stool samples. Each infant was assessed for FASD by triangulating data from infant dysmorphology examinations, neurodevelopmental assessments, and maternal interviews. The dada2 pipeline, PhyloSeq and vegan were used to process the data, calculate diversity measures and compute the statistical analyses of microbial composition.

Ruminococcus was lower (q = 0.0298) in women with infants with FASD, while Alloprevotella was higher (q = 0.0426) in these women. Bifidobacteria was higher (q = 0.0316) in infants diagnosed with FASD. A lower abundance of Bifidobacteria has been observed in children with Autism Spectrum Disorder (ASD), making this finding unexpected. Both Megasphaera (q = 0.0260) and Prevotella (q = 0.0269) were higher in infants diagnosed with FASD, a finding that mirrors findings in individuals diagnosed with ASD in other low- and middle-income countries.
The microbial differences observed in this study may contribute to the neurocognitive deficits’ characteristic of FASD. These findings are promising for microbe-based therapeutic interventions to reduce the extent of neurocognitive deficits and the debilitating symptoms associated with FASD.

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