H 2 is produced exclusively by bacteria in healthy individuals, significant numbers of such bacteria are found only in the colon. Hydrogen Breath Tests (HBT) determine the concentration of hydrogen gas (H 2) in exhaled air following the oral administration of carbohydrates. Because of the difficulty of integrating this method into clinical routine, it has become standard procedure to utilize indirect non-invasive methods for detecting SIBO based on changes caused by the metabolic activity of bacteria colonizing these bowel segments. ĭirect confirmation of SIBO is possible only by microbiological examination of aspirate from the proximal small bowel.

SIBO is characterized by a population corresponding to >10 5 CFU/ml of aspirate. Under physiological conditions, the proximal jejunum is characterized by a bacterial population corresponding to 10 3-10 4 colony forming units (CFU) per milliliter of aspirate. Small intestinal bacterial overgrowth (SIBO) represents an increased colonization by bacterial species derived from the colonic flora that may spread beyond the small bowel segments and sometimes affect the stomach.

The small bowel represents a transition zone between the stomach, which harbors low numbers of microorganisms, and the colon, with its high level of bacterial colonization. Because symptoms of SIBO are often difficult to differentiate from those caused by the underlying disease, targeted work-up is recommended in patients with corresponding clinical signs and predisposing factors. SIBO represents a frequently ignored yet clinically relevant complication in CD, often mimicking acute flare. SIBO rate was also higher in patients with affection of both the colon and small bowel, while inflammation of the (neo)terminal ileum again showed only tendential association with the development of SIBO. SIBO was significantly more frequent in patients with partial resection of the colon or multiple intestinal surgeries there was also a clear trend in patients with ileocecal resection that did not reach statistical significance. There was no correlation with the Crohn's Disease Activity Index. SIBO patients reported a higher rate of abdominal complaints and exhibited increased stool frequency (5.9 vs. Thirty-eight patients (25.3%) were diagnosed with SIBO based on positive findings at HGBT. One-hundred-fifty patients with CD reporting increased stool frequency, meteorism and/or abdominal pain were prospectively evaluated for SIBO with the Hydrogen Glucose Breath Test (HGBT). As result, CD patients may experience malabsorption and report symptoms such as weight loss, watery diarrhea, meteorism, flatulence and abdominal pain, mimicking acute flare in these patients.

Hence, patients with Crohn's Disease (CD) are especially predisposed to develop SIBO. Potential causes of SIBO include fistulae, strictures or motility disturbances. Small intestinal bacterial overgrowth (SIBO) is characterized by excessive proliferation of colonic bacterial species in the small bowel.

Bacterial overgrowth in stomach