Linking Gut Microbiota and Irritable Bowel Syndrome (Ibs): A Review

Irritable bowel syndrome (IBS) is a chronic gastrointestinal disorder with an increasing global prevalence. The International Classification of Diseases (ICD) system typically categorizes IBS into four subtypes based on symptomatology. The objective of this review is to provide a concise synthesis of the most current information regarding IBS, encompassing widely accepted diagnostic criteria, etiology, epidemiological data and the significance of gut microbiota (GM) in pathogenesis of this disorder. Additionally, it will explore future perspectives. Recent studies have demonstrated that the GM in healthy individuals primarily consists of four main bacterial phyla: Firmicutes spp., Bacteroidetes spp., Actinobacteria spp., and Proteobacteria spp. Dysbiosis or an imbalance in these bacteria may be a contributing factor to the IBS development. It is imperative to acknowledge the multifaceted role of the GM in several essential biological processes, including: immunomodulation, intestinal barrier integrity, gut microbiota-gut-brain axis (GBA) or nutrient absorption. The composition of GM is subject to variation depending on the IBS subtype. Many therapeutic strategies have been devised for the treatment of patients with IBS, comprising antibiotics, probiotics, prebiotics, synbiotics and fecal microbiota transplantation (FMT). Although FMT has shown promise, clinical trials outcomes remain still inconsistent. Dietary interventions and psychological support are also vital components of IBS management.

Despite the advances in understanding the GM-IBS relationship, there is still a lack of knowledge regarding specific microbial markers for each IBS subtype. Consequently, a definitive microbiota pattern has yet to be delineated. However, emerging evidence underscores the microbiome’s role in IBS pathophysiology.