The trajectory of gut microbiota assemblage during the first year of life plays a vital role in identifying risks for atopic sensitization, according to an observational study published in Gastroenterology.

Early-life gut microbiota appear to have a role in developing atopic diseases, but ecological changes to gut microbiota during infancy in relation to food sensitization remain unclear. Researchers sought to characterize and associate these changes with the development of food sensitization in children by characterizing the composition of 2844 fecal microbiota samples in 1422 Canadian full-term infants using 16S rRNA amplicon sequencing. Atopic sensitization outcomes were measured by skin prick tests at age 1 year and 3 years and the association between gut microbiota trajectories and atopic sensitization outcomes was determined. Ethnicity and early life exposures influencing microbiota trajectories were initially examined, and post hoc analyses were conducted.

The researchers found four developmental trajectories of gut microbiota that were shaped by birth mode and varied by ethnicity. They found that the trajectory with persistently low Bacteroides abundance and high Enterobacteriaceae/Bacteroidaceae ratio throughout infancy increased the risk of sensitization to food allergens, especially to peanuts, at age 3 years by 3-fold.


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Interestingly, a much higher likelihood for peanut sensitization was found if infants with this trajectory born to Asian mothers. It was characterized by a deficiency in sphingolipid metabolism and persistent Clostridium difficile colonization. Importantly, this trajectory of depleted Bacteroides abundance mediated the association between Asian ethnicity and food sensitization.

“This study documented an association between persistently-low gut Bacteroides abundance throughout infancy and sensitization to peanuts in childhood,” concluded the authors. They added, “These findings further support the future development of microbiota-based preventive or therapeutic intervention strategies for food allergy in toddlers.”

References

Tun HM, Peng Y, Chen B, et al. Ethnicity associations with food sensitization are mediated by gut microbiota development in the first year of life. Gastroenterol. Published online March 15, 2021. doi: 10.1053/j.gastro.2021.03.016