BackgroundDientamoeba fragilis is a protozoan parasite of the human gastrointestinal tract and still controversial in association with gastrointestinal symptoms.PurposeWe present cross-sectional study of the prevalence of D. fragilis, and sociodemographic and clinical features in the patients with gastrointestinal symptoms.MethodsA total of 490 fecal specimens were collected from outpatients with gastrointestinal symptoms in the Department of Parasitology, Faculty of Medicine, Ege University and Celal Bayar University, Turkey. Fecal specimens were examined with microscopy and inoculated in Robinson medium. D. fragilis-positive samples were examined for the presence of other intestinal parasites using enzyme immunoassay. Real-time PCR analysis was performed on all samples.ResultsOf the 490 stool specimens examined by real-time PCR, 59 patients were positive for D. fragilis infection with prevalence rate of 12.04%. Forty-four of positive patients (74.5%) were found to be infected with only D. fragilis, while 23.7% were co-infected with Blastocystis and 1.7% were co-infected with Rotavirus. No statistically significant difference was found in all the examined patients in terms of D. fragilis positivity for all sociodemographic parameters. Loose stool consistency was associated with the presence of D. fragilis, with 18.3% (P=0.001). When the clinical symptoms of all the patients participating in this study were examined, diarrhea was statistically more significant in patients with the presence of D. fragilis (16.3%; P=0.001). The rate of diarrhea in D. fragilis-positive patients (84.09%; P=0.0005) was higher than that of D. fragilis-negative patients and it was statistically significant.ConclusionThis study is important for assessing the prevalence of D. fragilis and its association with other factors in symptomatic patients in a large sample group in Turkey, as well as investigating the relationship of identified symptoms with the D. fragilis pathogenicity. It is suggested that D. fragilis in this case is not a commensal parasite but a pathogenic parasite and that the most common clinical symptom is diarrhea.