Baby-to-baby strain transmission shapes the developing gut microbiome.

Area of Science:

• Microbiome research
• Infant health
• Social epidemiology

Background:

• The early infant microbiome is primarily influenced by maternal transmission.
• The role of interpersonal transmission among infants in shaping the microbiome during the first year is not well understood.

Purpose of the Study:

• To investigate microbial strain transmission within nursery settings.
• To model how social interactions influence the infant gut microbiome in the first year of life.

Main Methods:

• Conducted a metagenomic survey of 134 individuals (babies, educators, families).
• Collected 1,013 longitudinal fecal samples from babies during their first year in nursery.
• Tracked microbial strain transmission within and between nursery groups across three facilities.

Main Results:

• Extensive baby-to-baby microbiome transmission was observed within nursery groups after one month.
• Nursery-acquired strains contributed significantly to the infant gut microbiome, comparable to family-acquired strains.
• Microbiome transmission networks became more intricate over the nursery year, influenced by factors like having siblings and antibiotic treatment.

Conclusions:

• Interpersonal transmission between babies is a major driver of infant microbiome development in nursery settings.
• Social interactions in infancy are critical for shaping the developing gut microbiome.
• Antibiotic treatment significantly increased the influx of new microbial strains into the infant gut.