# A public resource of 15 genomically characterized representative strains of Shigella sonnei

## TL;DR

Researchers created a public collection of 15 diverse Shigella sonnei strains with full genome data to better study this disease-causing bacterium.

## Contribution

The study provides a publicly accessible set of genomically characterized S. sonnei strains representing current diversity and including the pINV plasmid.

## Key findings

- The 15 S. sonnei strains represent diverse phylogenetic lineages and epidemiological patterns.
- Complete genome sequences reveal ongoing adaptive evolution through insertion sequences and structural changes.
- The pINV invasion plasmid was preserved in these isolates, unlike many public datasets.

## Abstract

Shigella sonnei is rapidly emerging as the dominant agent of shigellosis, an enteric disease responsible for a significant burden of morbidity and mortality worldwide. Whole-genome sequencing of S. sonnei isolated over the last three decades has revealed phylogenomic diversity within the population and the emergence of multiple lineages associated with distinct epidemiological patterns such as resistance to critical antimicrobials and/or transmission within different groups. However, most experimental work on S. sonnei biology and pathogenicity has focused on a single laboratory strain (53G), which is phylogenetically distant from currently circulating strains. Here, we introduce a set of phylogenetically diverse and epidemiologically relevant S. sonnei isolates made available through publicly accessible culture collections as a resource for laboratory science. We present their complete whole-genome sequences, including the pINV invasion plasmid (missing from a large proportion of public genome data due to loss during laboratory culture). Finally, the characterization and comparison of these complete genome sequences highlight evidence for ongoing adaptive evolution in S. sonnei, featuring the accumulation of insertion sequences, gene pseudogenization and structural variation.