Dr Ouli Xie

Postdoctoral Fellow (ESPOD)

I am an infectious diseases physician and scientist with an interest in bacterial pathogens. My research focuses on the interaction between bacteria, the microbiome, and the host and how that shapes human disease.

My current work focuses on the interaction between the human pathogen, Staphylococcus aureus, the nasal microbiome, and the host to investigate the underpinnings of S. aureus carriage in the nose. I use large scale pathogen and shotgun metagenomic sequencing to investigate multi-strain carriage, co-evolution, and competition during carriage while incorporating host health data. I aim to use these methods to develop new ways to understand why pathogen carriage and disease varies across individuals while expanding these approaches to other bacterial pathogens which reside in the respiratory tract.

I am an infectious diseases doctor by training and have worked as a specialist physician across Melbourne and Darwin, Australia. I completed my PhD in 2025 at the Peter Doherty Institute for Infection Immunity, Australia, under Prof Steven Tong, A/Prof Mark Davies, and Prof David Ascher. During my PhD, I coordinated the development of a consortium of hospitals to investigate the epidemiology of invasive Streptococcus pyogenes (group A Streptococcus) and Streptococcus dysgalactiae subsp. equisimilis (SDSE) disease across Australia. Combining clinical, pangenome-informed evolutionary analyses, and transmission modelling, I brought to the fore the burden of SDSE disease in Australia while demonstrating the close cross-species relationship between SDSE and S. pyogenes. These data and methods have subsequently been adopted in international collaborative surveillance projects, vaccine development efforts, and clinical trials to optimise treatment of streptococcal disease.

My timeline

• EMBL-EBI-Sanger Research Fellowship (ESPOD)

• PhD, University of Melbourne

• Fellow of the Royal Australasian College of Physicians

• MBBS (Hons.), BMedSci, University of Melbourne