The relationship between IBD and gut microbiota

Abstract

Background: IBD is a chronic inflammatory bowel disease of unknown aetiology, forming part of a process via which failure in homeostatic interactions between genetic, immune, and environmental factors, triggers immune-mediated inflammation. Aims: The primary aim of the study was to determine the faecal microbiota present in a cohort of newly diagnosed IBD patients who were treatment-naïve and compare them with a cohort of controls. The secondary aim was to determine the clinical characteristics of the newly diagnosed IBD patients. Methodology: An observational, prospective and inception cohort study was carried out between the relationship of IBD and gut microbiota. Via this cohort study, the clinical course, progression, and treatment of all patients diagnosed with IBD between January 2018 and September 2019, in the Maltese Islands, were included. All the recruited patients were asked to answer a set of questions pertaining to their demographic data, daily habits, and particular environmental factors. Results: 100 patients were included in the newly diagnosed IBD group and 97 patients in the control group. From the 100 patients which were newly diagnosed 57 patients accepted to be recruited in this study. From the cohort of CD patients, the majority presented with L1 disease (51%), followed by L3 (26%) and L2 (23%) disease. Our UC cohort were noted to mostly present with E2 disease (50%), followed by E1 (46%) and E3 disease (4%), respectively. Our treatment-naïve CD cohort, was noted to have a predominance of specific bacteria, including Lactobacillus gasseri, ASV 249- Parasutterella unlc., Candidatus-Saccharibacteria and Acteroides clarus. These bacteria were commonly present in various international CD microbiota, therefore associating them with a CD microbiome. The UC cohort was found to have an increase in the number of the bacteria: ASV 6- Escherichia/Shigella Uncl., ASB_41-Sutterella wadsworthensis, ASV 44- Bacteroides faecis and Actinobacteria. These were also commonly found in international studies, and such phyla linked to a UC microbiome. In our control group a predominance of other bacteria was noted: ASV 321 (Clostridia Uncl.), ASV 96 (Rumminococcaceae uncl.), Akkermansia muciniphila (ASV 20) and Alistipes uncl. (ASV 61). All these are proposed as potential biomarkers for healthy gut status. Conclusion: So far, few studies have managed to investigate the microbiome’s effect on the manipulation of the IBD disease activity, therefore such topic generates great interest. The use of beneficial bacteria to yield new treatments for IBD patients is one of the potential new paths, whereby targeted treatment approach using specific bacteria can theoretically be prescribed to IBD patients so to re-establish their normal environment.