Bacterial strains shared within a home

Abstract

Infants are born without microbial passengers and acquire them early in life. Researchers know that particular microbial species transmitted during childbirth and nursing seed an infant’s microbiome, but that microbiome becomes more complex as that infant grows into an adult. “One of the open questions is, ‘Why do we get the strains that we get?’” says microbial evolutionary biologist Nandita Garud of the University of California, Los Angeles. In a new study, researchers led by Nicola Segata at the University of Trento find that the people we are nearest to may provide the answer. Close social contact is an important predictor of which bacterial strains within species get shared between people ( Nature 2023, DOI: 10.1038/s41586-022-05620-1 ). Working with oral and gut microbiome DNA sequences from more than 9,700 people around the world, Segata and colleagues used evolutionary relationships between genes unique to each bacterial species to identify strains. When