A new subspecies of beneficial bacteria discovered in newborns

It has been named Bifidobacterium longum subsp. iuvenis, thus proving to be a new subspecies of beneficial bacteria found in the children gut. It belongs to the Bifidobacterium longum species, a typical component of a healthy gut microbiota. This discovery could lead to new diets and targeted foods to promote healthy growth in children.

"In the human gut microbiota, different species of bifidobacteria are present in different stages of life; specifically, in infants, Bifidobacterium longum subsp. infantis has been known to possess the ability to use oligosaccharides from breast milk as a source of nourishment," explains Paola Mattarelli, professor at the Department of Agricultural and Food Sciences (DISTAL) at the University of Bologna, one of the study's authors. "Thanks to this study, we have described a new subspecies of Bifidobacterium longum that develops during weaning when solid foods are introduced into the child's diet alongside breast milk."

Bifidobacteria are a key component within the complex bacterial community of the human gut microbiota and exert multiple host health-promoting effects upon their host. Notably, due to their beneficial properties, they are one of the most used components in probiotic products. Currently, 112 species have been recognized, with 12 typically present in humans. Among them, one of the most common is Bifidobacterium longum, which, in turn, has several subspecies.

In 2022 a new gut bacterium prevalent in the gut of Bangladeshi weaning infants has been found. Most infants in the study were exclusively breastfed for the first six months, and then, during weaning, the introduction of solid food was always associated with breast milk. DISTAL researchers in collaboration with Nestlé scientists have now officially described this new bacterium as Bifidobacterium longum subsp. iuvenis.

"This new group of bifidobacteria shows unique nutritional features being able to ferment both oligosaccharides from breast milk and fibers derived from solid foods, and its abundance in the gut increases when children's diets are diversified," says Mattarelli. "Moreover, this new species interacts with the other microbial gut groups, playing an important role in intestinal ecology and overall metabolism."

The newly identified subspecies is the twenty-seventh species of bifidobacteria described in the laboratory of Agroenvironmental and Food Microbiology at the University of Bologna from 2014 to present.

The study has been recently published in the International Journal of Systematic and Evolutionary Microbiology with the title "Bifidobacterium longum subsp. iuvenis subsp. nov., a novel subspecies isolated from the faeces of weaning infants". For the University of Bologna Monica Modesto, Donatella Scarafile, and Paola Mattarelli participated in the study.