Looking for bacterial signatures associated to IBS symptoms after FMT treatment

The diagnosis and management of irritable Bowel Syndrome (IBS) is challenging due to its complex symptoms and inconsistent treatment responses. Fecal microbiota transplantation (FMT) has become a promising intervention, highlighting the vital role of gut microbiota in gastrointestinal health. We describe the case of a 55-year-old woman without prior gastrointestinal issues who, following a severe depression, developed multiple gastrointestinal symptoms, including abdominal pain, fluctuating bowel habits, and a persistent burning sensation in her mouth and upper gastrointestinal tract. She was diagnosed with IBS resistant to multiple lines of treatment at Lausanne University Hospital, where a multidisciplinary team proposed multiple oral FMT. One month post-FMT, her gastrointestinal symptoms significantly improved and remained better after a year, with only the burning sensation persisting. Analysis of pre- and post-FMT samples, and the donor material, using 16S rRNA amplicon metagenomics, revealed a 90% genus-level taxonomic overlap between the patient and the donor. Changes in the relative abundance of these genera likely facilitated her recovery. The elimination of IBS-associated genera and enrichment of beneficial gut commensals were also observed. While not assessed, other microorganisms and metabolites may have contributed to the therapeutic effects. Overall, FMT led to substantial improvement of her long-standing gastrointestinal symptoms.