Role of Dientamoeba fragilis and Blastocystis spp. in Irritable Bowel Syndrome

We investigated the prevalence of Dientamoeba fragilis and Blastocystis spp. in IBS patients and evaluated whether there was a possible link between IBS and these parasitic infections. Stool specimens collected from 55 IBS patients, 80 patients with gastroenteritis as control group 1 (CG-1) and 50 healthy volunteers as control group 2 (CG-2) were included the study. Samples were examined by direct microscopy, trichrome staining and culture methods. While there was no significant difference in the prevalence of Blastocystis spp. between IBS patients and CG-1 (p > 0.05), a significant difference was found between IBS and CG-2 (p < 0.05). Patients with IBS were found to have five or more Blastocystis spp. per field than control groups. After eradication, all symptoms were cured in four patients, there were only constipation problems left in eleven patients and there were no changes in clinical findings in three patients. D. fragilis was not found in any of the samples. The reason we did not find any D. fragilis may be due to the low infection rate in the region. However, significantly having five or more Blastocystis spp. per field (X40) in IBS patients and regression of IBS symptoms after treatment in most of the patients suggested a possible link between IBS and Blastocystis spp.