Study Shows How Breastfeeding Protects Newborns from Resistant Organisms

by the bioMérieux Connection Editors

Do infants benefit from a gut bacteria that helps young children fend off antimicrobial resistant organisms? The gut microbiome of infants is dominated by Bifidobacterium, a species that produce acids that suppress the growth of other taxa of bacteria that might be more likely to contain antimicrobial resistance genes (ARGs). Bifidobacterium have a low likelihood of carrying these genes.

“Given that AMR is a growing public health crisis and ARGs are present in the gut microbiome of humans from early life, this study examines the correlation between a Bifidobacterium-dominated infant gut microbiome and AMR levels,” according to the researchers from the University of California, Davis.

The UC Davis team studied a group of Bangladeshi infants and used a culture-independent metagenomic approach to compare the degree of Bifidobacterium in the guts of these children shortly after birth and then again when the children became toddlers.

“In general, Bifidobacterium dominance is associated with a significant reduction in AMR in a Bangladeshi cohort, both in the number of acquired AMR genes present and in the abundance of AMR genes. However, by year 2, Bangladeshi infants had no significant differences in AMR related to their early-life Bifidobacterium levels,” wrote the research team.

The research team linked this drop to breastfeeding. Nursing appears to promote the growth of the microbes like Bifidobacterium, which thrive on oligosaccharides in breast milk.

Bifidobacterium can be very dominant as long as an infant is breastfed, and then bacterial levels drop off during weaning,” says Diana Taft, the lead researcher.

Previous studies have found that children in middle- and lower-income countries, where children often nurse for two years or more, have higher levels of Bifidobacterium than children in developed countries like Finland or Sweden, where children often stop nursing by one year of age.

The UC Davis team concluded that high levels of Bifidobacterium are associated with reduced levels of AMR in early life. As such, Bifidobacterium constitute a “commensal” organism for infants with high levels of gut Bifidobacterium. Commensalism is a form a symbiosis. Whereas both organisms benefit from symbiotic relationships, only one benefits in a commensal relationship, while the second simply participates without direct benefit.

The UC Davis team concluded in its Msphere.com paper, “This study demonstrates that high levels of Bifidobacterium are associated with reduced levels of AMR in early life and suggests that probiotic interventions to increase infant Bifidobacterium levels have the potential to reduce AMR in infants.”


Opinions expressed in this article are not necessarily those of bioMérieux, Inc.

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