Irritable bowel syndrome in Egyptian patients: plausible risk factors and association with intestinal protozoa.

The pathogenesis of irritable bowel syndrome (IBS) is not yet clear. Our study suggested parasitic infection and other plausible risk factors among Egyptian IBS patients. We studied 40 IBS patients diagnosed according to Rome III criteria (Group I), 40 with other gastrointestinal symptoms (Group II) and 40 healthy controls (Group III). Stool samples were examined using direct wet smear, sedimentation technique, trichrome stain and immune-chromatographic tests for Cryptosporidium parvum. IBS patients displayed a significantly greater percentage of Blastocystis hominis infection (45%) than non-IBS patients (20%) and healthy controls (10%). Dientamoeba fragilis was identified in two IBS patients. Detection of B. hominis was independent of demographic characters, IBS subtype, Helicobacter pylori infection or medications, but with a positive association with a history of antibiotic intake with IBS.