Poster Presentation 15th Lorne Infection and Immunity 2025

Phocaeicola dorei abundance is discriminatory between health and endometriosis in Australian women (#343)

Yenkai Lim 1 , Rebecca Burgell 2 , Judith Moore 2 , Dakota Rhys-Jones 2 , Roni Ratner 3 , Peter Gibson 2 , Jane Varney 2 , Jane Muir 2 , Mark Morrison 1 4 5
  1. Frazer Institute, Faculty of Medicine, University of Queensland, Brisbane, Australia
  2. Department of Gastroenterology, Monash University, Melbourne, Australia
  3. Department of Obstetrics and Gynaecology, Monash University, Melbourne, Australia
  4. Department of Medicine, University of Melbourne, Melbourne, Australia
  5. Department of Gastroenterology and Hepatology, Princess Alexandra Hospital, Brisbane, Australia

Background: Endometriosis affects approximately 15% of women >50 years old. Its pathophysiology is poorly defined but appears to involve oestrogen-dependent immune dysregulation and inflammation leading to painful symptoms. Women with endometriosis are also more likely to experience irritable bowel syndrome (IBS), implicating the gut microbiome and perhaps dietary intervention in its diagnosis and management. Here, we present our initial findings of the metagenomic analysis of the stool microbiota of women recruited as part of a larger study examining the low FODMAP diet as an intervention for symptom control in women with and without endometriosis. 

Methods: Stool samples were collected at enrolment from women diagnosed with (n=35) or without (n=21) endometriosis using DNA-Genotek collection kits. Subsamples of the stabilised stool samples were used for DNA extraction and metagenomic sequencing to a depth of 5 Gbp following standard protocols of the Australian Centre for Ecogenomics. The raw data was processed using FastQC and the quality-filtered data processed with the Kraken2 pipeline. The resulting taxonomic profiles were further analysed using the Rstudio environment.

Results: The Spearman correlation analyses of the 25 most abundant genera revealed the genus Phocaeicola being more prominent within the network identified from the endometriosis cohort and at the species level, P. dorei was specifically increased (Mann-Whitney U-Test: p<0.01, q<0.01). Interestingly, the endometriosis cohort could be further stratified into low and high P. dorei subgroups, and when these subgroups were compared with the control cohort, they could all be separated based on their Bray-Curtis dissimilarity metric (PERMANOVA analysis, p=0.021).

Conclusions: Our preliminary results suggest that the relative abundance of P. dorei is not only discriminatory of the stool microbiota in women with and without endometriosis, but perhaps, also between women with endometriosis. Further investigation is warranted including defining the relationship of this observation with IBS.