# A murine model of adult gastrointestinal colonization by Group B Streptococcus

## TL;DR

This study creates a mouse model to study how Group B Streptococcus colonizes the adult gut, identifying bacterial factors important for colonization.

## Contribution

The work introduces a new murine model and identifies GBS capsule as a key factor for GI colonization.

## Key findings

- A murine model of GBS colonization in the adult GI tract was successfully established.
- GBS capsule was identified as a critical factor for GI colonization in mice.
- Transposon sequencing revealed candidate GBS factors important for GI tract colonization.

## Abstract

Group B Streptococcus (Streptococcus agalactiae, GBS) is a leading cause of invasive infections in neonates and adults. The adult gastrointestinal (GI) tract represents an understudied site of asymptomatic carriage with potential relevance for both transmission and disease. Here, we establish a murine model of GBS colonization in the adult GI tract, which provides a tractable system for probing host-microbe interactions within this niche. Using this model, we establish that GI carriage is generalizable to diverse GBS isolates and leverage transposon sequencing (Tn-Seq) to identify candidate GBS factors important for GI colonization. Informed by these Tn-Seq data, we identify GBS capsule as a critical colonization factor of the adult murine GI tract. Taken together, this work highlights the GI tract as a reservoir for GBS and introduces a new experimental framework for investigating the bacterial and host determinants of GBS GI carriage.