Gut microbe could boost growth in malnourished infants

New research suggests that B. infantis can be used to treat children with acute malnutrition.
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What is already known on this topic
Every year, undernutrition kills about 3 million children, and more than 18 million children younger than five are affected by acute malnutrition — the most severe form of undernutrition that is responsible for nearly half of all undernutrition-related mortality. Recent studies have shown that acute malnutrition is associated with impaired development of the gut microbiota of children and infants.

What this research adds
Researchers explored the role of bifidobacteria, and in particular of the early gut colonizer Bifidobacterium infantis, as a probiotic treatment for malnourished infants in Bangladesh. At the start of the trial, the levels of B. infantis were lower in infants with acute malnutrition than in healthy infants. The researchers found that a standard milk-based therapy plus a strain of B. infantis cultured from a healthy US infant promoted weight gain and reduced gut inflammation in malnourished Bangladeshi infants. Follow-up experiments showed that a B. infantis strain cultured from a healthy child from Bangladesh boosted weight gain in mice colonized with the gut microbiota from an infant with acute malnutrition.

Conclusions
The findings suggest that B. infantis can be used to treat children with acute malnutrition. They also highlight how the development of the gut microbiota is associated to healthy growth in infants and children.

Every year, undernutrition kills about 3 million children — especially in low-income countries. New results from a clinical trial in Bangladesh show that the microbe Bifidobacterium infantis, an early colonizer of the human gut, could promote weight gain in malnourished infants.

The findings, published in Science Translational Medicine, suggest that B. infantis can be used to treat children with acute malnutrition. They also highlight how the development of the gut microbiota is associated to healthy growth in infants and children. 

Acute malnutrition, the most severe form of undernutrition, affects more than 18 million children younger than five and is responsible for nearly half of all undernutrition-related mortality. Recent studies have shown that acute malnutrition is associated with impaired development of the gut microbiota of children and infants

Scientists have known that the gut microbiota of healthy breastfed infants in the first few months of life is dominated by members of the genus Bifidobacterium, including B. infantis. To explore the role of B. infantis as a probiotic treatment for malnourished children, Jeffrey Gordon at Washington University School of Medicine and his colleagues conducted a trial in 62 Bangladeshi infants, aged 2 to 6 months, with acute malnutrition.

Gut colonizer

For 28 days, all study participants received a course of antibiotics and a milk-based formula recommended by the World Health Organization. One group received additional treatment with a commercially available strain of B. infantis cultured from a healthy US infant; a second group received the B. infantis strain plus a sugar from human breast milk; and a third group received lactose as a control. 

The researchers analyzed the gut microbiota of study participants before the treatment began, then again at day 28 and four weeks after the end of the treatment. At the start of the trial, the levels of B. infantis were lower in infants with acute malnutrition than in healthy infants. The gut microbiotas of malnourished infants were dominated by pathogens such as Shigella, Klebsiella, and Streptococcus.

Treatment with the B. infantis strain promoted weight gain in the Bangladeshi infants, the researchers found. However, its colonization levels were still lower than those documented in healthy Bangladeshi infants.

Boosting growth 

To identify B. infantis strains whose colonization levels could be comparable to those of healthy Bangladeshi infants, the researchers cultured strains from healthy children living in the same community as those with acute malnutrition. One strain in particular was able to thrive on plant-based carbohydrates consumed in the local diet.

So, the researchers transferred this strain to the gut of germ-free mice colonized with the microbiota of an infant with acute malnutrition. The Bangladeshi B. infantis strain was a more efficient colonizer than the US strain. It also boosted weight gain and reduced markers of gut inflammation in mice, which suggests that it can be used to treat malnutrition in Bangladeshi children.

However, the researchers note, future studies should test the effects of this newly discovered strain on children with acute malnutrition. “Bacterial strain selection is a critical element in designing future therapies for repairing dysfunctional gut microbial communities that lead to malnutrition,” Gordon says.