A new research project led by Dr Chris Bain from Alfred Health and Monash University is a groundbreaking investigation into why female patients face a higher risk of infection after cardiac surgery compared with males.
Cardiac surgery is the most common major surgical procedure performed in Australia, yet alarmingly up to 15 per cent of patients develop serious infections in the months following their operation. Notably infection risks are not uniform! Females not only experience infections more often but are infected by different bacterial profiles than males. Despite clear sex-specific differences, infection prevention and post- operative care are currently standardised for all patients.
This research project entitled "Multi-omic analysis to investigate sex-specific differences in the microbiome-host interaction after cardiac surgery," seeks to uncover biological mechanisms behind these disparities. This will examine how immune responses and the gut microbiome (the diverse community of bacteria in the digestive system) interact differently in male and female patients after surgery, and whether these differences can predict infection risk within 90 days.
The study draws on the CALIPSO (Duration of Cardiac Antimicrobial ProphyLaxIS Outcomes Study) trial, a large ANZCA Clinical Trials Network endorsed study that is evaluating the optimal duration of antibiotic use after cardiac surgery. Leveraging CALIPSO’s existing infrastructure, ethical approvals, consumer support and patient recruitment has made possible the collection of gut bacterial samples and immune cells from patients before and after surgery. The research team will conduct a "multi-omic" analysis, integrating detailed information on gene activity related to immune function with data on the gut microbiome.
The project brings together a multidisciplinary team of experts in clinical trials, perioperative genomics, infection prevention, and computational biology.
Ultimately the CALIPSO multi-omic study aims to identify biological markers that distinguish infection susceptibility between sexes, paving the way for precision-based infection prevention strategies in cardiac surgery. This novel approach moves beyond current risk models that do not account for sex-specific differences.
By linking high quality clinical trials and advanced molecular analysis this project represents a vital step towards Precision Gender Medicine, ensuring that both female and male patients receive care informed by their unique biological response to surgery.
Dr Chris Bain, Professor Trisha Peel, Professor Paul Myles Alfred Health and Monash University, Melbourne, A/Professor Stefan Dieleman, Westmead Hospital, Western Sydney University, NSW, Dr Kiymet Bozaoglu, Murdoch Children’s Research Institute, University of Melbourne, A/Professor Mark Ziemann, Burnet Institute, Melbourne, Dr Brian Forde, Institute of Molecular Biosciences, The University of Queensland.
The project was awarded A$69,500 funding through the ANZCA research grants program for 2026.