What the study found
The study found extensive baby-to-baby transmission of microbial strains in nursery groups during the first year of nursery attendance. By the end of the first term, nursery-acquired strains accounted for a proportion of the infant gut microbiome comparable to that from family.
Why the authors say this matters
The authors conclude that social interactions in infancy are crucial drivers of infant microbiome development. They also suggest that transmission between babies is an important part of how the developing gut microbiome is shaped in the first year.
What the researchers tested
The researchers carried out a metagenomic survey, which means they analyzed genetic material from microbial communities, in nursery settings involving babies attending the first year, their educators, and their families. They collected 1,013 stool samples from 134 individuals across three nursery facilities and tracked microbial strain transmission within and between nursery groups over time.
What worked and what didn't
Baby-to-baby transmission was detected after only one month of nursery attendance and continued to increase over the nursery year. The transmission network became more complex over time, with single strains spreading in some classes and multiple patterns of strain acquisition and species transmissibility observed; having siblings was associated with higher microbiome diversity and less strain acquisition from nursery peers, while antibiotic treatment was the condition most linked to increased influx of strains.
What to keep in mind
The summary describes a nursery-based survey, so the findings apply to the settings and groups studied. The abstract does not provide additional limitations beyond the study scope described here.
Key points
- Extensive baby-to-baby strain transmission was detected in nursery groups.
- Nursery-acquired strains reached a proportion of the infant gut microbiome comparable to family-derived strains by the end of the first term.
- Transmission continued to grow over the nursery year and formed a more intricate network over time.
- Having siblings was linked to higher microbiome diversity and less strain acquisition from nursery peers.
- Antibiotic treatment was the condition most associated with increased influx of strains.
Disclosure
- Research title:
- Baby-to-baby strain transmission shapes infant gut microbiome
- Authors:
- Liviana Ricci, Vitor Heidrich, Michal Punčochář, Federica Armanini, Matteo Ciciani, Amir Nabinejad, Farnaz FAZAELI, Elisa Piperni, Charlotte Servais, Federica Pinto, Mireia Valles‐Colomer, Francesco Asnicar, Nicola Segata
- Institutions:
- European Institute of Oncology, European Institute of Oncology, European Institute of Oncology, European Institute of Oncology, King's College London, King's College School, Universitat Pompeu Fabra, University of Trento, University of Trento, University of Trento, University of Trento, University of Trento, University of Trento, University of Trento, University of Trento, University of Trento, University of Trento
- Publication date:
- 2026-01-21
- OpenAlex record:
- View
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