S1710 The Temporal Association Between Acute Gastroenteritis and the Onset of Inflammatory Bowel Disease: A Systematic Review

Introduction: It has long been believed that acute gut infections can trigger inflammatory bowel disease (IBD) in people who are genetically at risk. Gut infections can set off abnormal immune reactions or affect the microbes in the digestive system, which, in certain cases, can cause Crohn’s disease (CD) or ulcerative colitis (UC). Methods: We systematically reviewed studies examining the link between gastrointestinal infections and subsequent IBD development. A 2025 search of PubMed, Embase, and other databases identified cohort and case-control studies involving bacterial or viral gastroenteritis preceding IBD. We assessed specific pathogens, relative risks or odds ratios, and timing of IBD onset. Associations with helminth exposure were also noted. Due to study heterogeneity, a qualitative synthesis was conducted. Results: We found 26 relevant studies through the selection process. There is strong and ongoing evidence that some infections in the gut can increase the chance of developing IBD. It was found that infection with Salmonella, Campylobacter, and Clostridioides difficile bacteria, commonly known as bacterial gastroenteritis, substantially raised the risk of IBD after infection. An analysis of a large group of people found that a history of these infections significantly increased the risk of Crohn's disease for a year after infection. Inverse associations exist between infections by Helicobacter pylori and helminths and the risk of IBD, suggesting that some common pathogens may shield people from the disease. Acute GI infections play a role in causing IBD in some patients. When infections occur, they can cause an inflammatory change in gut microorganisms and weaken mucosal barriers, possibly leading some susceptible hosts into persistent immune system disorders. Conclusion: A subset of irritable bowel syndrome cases develops as a result of GI infections. Our study shows that entering bacterial infections can increase the risk of Crohn's disease and ulcerative colitis, but that H. pylori and intestinal helminths may have the opposite effect. Based on what we know from epidemiology, microbes play an important part in the development of IBD. Gastroenteritis makes IBD likely in patients who develop new GI symptoms after the infection, so clinicians should suspect it. Taking steps to avoid and quickly deal with GI infections and possibly help restore the microbiome after infection could be valuable in addressing IBD development in those most likely to get it. Prospective investigations are necessary to uncover what causes IBD and determine which infections cause the most risk.