The role of small intestinal bacterial overgrowth in inflammatory bowel diseases

ABSTRACT The Role of Small Intestinal Bacterial Overgrowth in Inflammatory Bowel Diseases Ulcerative colitis (UC) and Crohn's disease (CD) are chronic inflammatory diseases of unknown etiology of the gastrointestinal tract. Both of diseases have been suggested to result in an exaggerated immune response to various antigens or environmental factors in genetically susceptible individuals. These two groups of diseases have many common symptoms such as diarrhea, bloody stool, weight loss, abdominal pain, fever and fatigue. These symptoms, which are common in patients with ulcerative colitis and Crohn's disease, can also be seen in the presence of small intestinal bacterial overgrowth (SIBO). This distinction is important, especially in the acute episodes when SIBO can be treated with antibiotics. SIBO is defined as clinical and laboratory demonstration of the association between the qualitative and/or quantitative changes of intestinal microbiota and maldigestion/malabsorption. As well as causing typical symptoms (steatore, diarrhea, protein-losing enteropathy, specific conditions of insufficiency), SIBO may also be presented as milder symptoms (gas, swelling, e.g. SIBO with irritable bowel syndrome) without causing malabsorption/ maldigestion. Therefore, SIBO is an overlooked factor among the common diseases. The aim of this study was to investigate the frequency of SIBO presence in patients with ulcerative colitis and Crohn's disease and the relationship of SIBO presence with disease activation, disease localization and disease duration. The study was conducted with 3 groups including a total of 116 people consisting of 40 ulcerative colitis patients and 35 Crohn's patients who had been diagnosed with inflammatory bowel disease (IBD) in Başkent University Medical Faculty Hospital Department of Gastroenterology and resorted to polyclinic between 27.09.2017-04.04.2018 and 41 healthy volunteers. Following the administration of oral glucose solution to the participants, breath H2 and CH4 levels were measured using the Quintron Breath Tracker. In addition, recent routine outpatient blood tests (c-reactive protein, fecal calprotectin, hemogram, transferrin saturation, vitamin B12 levels) were analyzed for the patient group with IBD. SIBO-positive was detected in 14 (12.1%) and SIBO-negative was detected in 102 (87.9%) of the total 116 patients included in the study. According to group distribution; SIBO-positive in 6 (15%) and SIBO-negative in 34 (85%) of the patients with ulcerative colitis, SIBO-positive in 5 (14.3%), SIBO-negative in 30 (85.7%) of the Crohn's patients; SIBO-positive in 3 (7.3%) and SIBO-negative in 38 (92.7%) of the healthy control group were detected. CH4 positivity was also assessed in patients with no SIBO in our study, and CH4-positive was detected in 48 (41.4%) and CH4-negative in 68 (58.6%) of 116 patients. According to group distribution; CH4-positive was detected in 17 (42.5%) and CH4-negative was detected in 23 (57.5%) of the patients with ulcerative colitis, CH4-positive was detected in 14 (40%) and CH4-negative was detected in 21(60%) of the patients with Crohn's disease, CH4-positive was detected in 17 (41.5%) and CH4-negative was detected in 24 (58.5%) of the healthy control group. It is important to detect SIBO, especially in cases of acute exacerbations, when SIBO may be treated by antibiotics in patients with IBD. In the future, prospective studies should continue to examine the role of SIBO in the evaluation and management of IBD patients. Keywords: Ulcerative colitis, Crohn's disease, breath test, small intestinal bacterial overgrowth