Investigation of intestinal parasites by conventional and molecular methods in children with gastrointestinal system complaints

Intestinal parasitic infections are a global health problem that causes morbidity and mortality, especially in children living in rural areas. In this study, stool samples of pediatric patients with gastrointestinal complaints were examined by conventional and molecular methods to determine the prevalence of intestinal parasites. A total of 100 pediatric patients with gastrointestinal complaints and 50 healthy children were included in the study. Stool samples were collected from each child and examined by direct microscopic examination (native-Lugol method), formol-ethyl acetate concentration technique, Kinyoun's acid-fast staining, and Wheatley trichrome staining methods. Real-time PCR was used for the detection of Blastocystis spp. and D. fragilis in the stool samples. Sanger sequencing was used to identify Blastocystis spp. subtypes. One or more intestinal parasites were found in 12% (n = 100) of the patient group and 1% (n = 50) of the control group using conventional techniques. By using real-time PCR, Blastocystis spp. was discovered in 14% (14/100) of the patient group and 8% (4/50) of the control group. There was no significant difference in the frequency of Blastocystis spp. between the two groups. The most prevalent Blastocystis subtype was ST1 and the most frequent allele was a2 among the samples successfully amplified and sequenced. D. fragilis was detected in 17% (17/100) of the patient group and 8% (4/50) of the control group by real-time PCR. The prevalence of D. fragilis was not significantly different between the patient and control groups, as well. Blastocystis spp. and D. fragilis were found in high prevalence in pediatric patients with gastrointestinal complaints in this study. Although the role of these protists as a pathogen in humans is still controversial, it is supposed to the presence of the parasites are associated with gastrointestinal disorders such as diarrhea, abdominal pain, nausea, and vomiting. More case-control studies are needed to understand the pathogenic or commensal role of these parasites on the intestinal microbiota, especially in both patients with gastrointestinal disorders and healthy individuals.