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

Abstract

Background and aims: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. Methods: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 sp. and D. fragilisin the stool samples. Sanger sequencing was used to identify Blastocystissp. subtypes. Results: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 sp. was discovered in 14% (14/100) of the patient group and 4% (4/50) of the control group. There was no signi cant difference in the frequency of Blastocystis sp. between the two groups. The most prevalent Blastocystissubtype was ST1 and the most frequent allele was a2 among the samples successfully ampli ed 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. fragiliswas not signi cantly different between the patient and control groups, as well. Conclusions:Blastocystis sp. 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.

No evidence of pathogenicity of Dientamoeba fragilis following detection in stools: A case-control study

“…Of these case-control studies, a very small number identified potential pathogenicity of D. fragilis in association with more frequent gastrointestinal symptoms or diarrhoea in groups carrying the protozoan [ 2 , 28 ]. The vast majority of comparative studies using D. fragilis PCR assays as a diagnostic method demonstrated no statistically significant difference in terms of the frequency of gastrointestinal signs between patients with the parasite in their stools and negative control subjects [ 14 , 16 , 17 , 19 , 20 , 25 , 26 , 31 ], or even a higher incidence of D. fragilis detection in asymptomatic patients than in symptomatic ones [ 3 – 5 ]. Very recently, in a large study that included nearly 28,000 patients, Shasha et al showed a significantly lower occurrence of digestive symptoms [adjusted OR 0.82 (0.76–0.88)] in patients testing positive for D. fragilis on PCR assay compared to control patients negative for this parasite [ 36 ].…”