Fecal microbiota transplant on Escherichia-Shigella gut composition and its potential role in the treatment of generalized anxiety disorder: A systematic review

Background: The gut-brain-axis has a role in mental health disorders. In people with generalized anxiety disorder, GAD,¹ normal flora Escherichia-Shigella, are significantly elevated. Fecal microbiota transplant, FMT,² has been used to alter the gut composition in unhealthy individuals. There may be a role for FMT in the treatment of GAD to improve the gut-brain-axis.

Methods: A systematic review of literature was conducted on articles published in PubMed, CINAHL Plus, Scopus, Cochrane Library, and Wed of Science from 2000 to 2022 that analyzed FMT as a modality to alter the gut microbiome in which Escherichia-Shigella levels were quantified and reported.

Results: Of 1916 studies identified, 14 fit criteria and were included. Recipients undergoing FMT procedures had at least one enteric diagnosis and increased percentages of Escherichia-Shigella pre-FMT. Five studies on recurrent Clostridioides difficile infection, three irritable bowel syndrome, two ulcerative colitis, one ulcerative colitis and recurrent Clostridioides difficile infection, one acute intestinal and chronic graft-vs-host disease, one pouchitis, and one slow transit constipation. 10 articles (71.4 %) showed decreased levels of Escherichia-Shigella post-FMT compared to pre-FMT. Four studies claimed the results were significant (40 %).

Limitations: Limitations include potential bias in study selection, study methods of analysis, and generalization of results.

Conclusions: The gut-brain-axis has a role in GAD. Those with GAD have significantly higher Escherichia-Shigella compared to those without GAD. FMT has the potential to decrease Escherichia-Shigella in patients with GAD to positively alter the gut-brain-axis as a potential for future GAD treatment.