The investigation of dientamoeba fragilis frequency in fecal samples of enterobius vermicularis positive cases by PCR

The aim of the present study was to investigate the coexistence of Enterobius vermicularis (E. vermicularis) and Dientamoeba fragilis (D. fragilis) in cases that sent cellophane tapes and fecal samples from different departments in Parasitology Laboratory of Aydin Adnan Menderes University, Application and Research Hospital, in addition, to determine D. fragilis genotypes. Another aim of the study was to compare the trichrome staining and polymerase chain reaction (PCR) methods in the diagnosis of D. fragilis. For this purpose, fecal samples from 148 cases were included in the study, 74 were positive for the presence of E. vermicularis eggs in cellophane tape samples and 74 were negative. The positivity of D. fragilis was investigated by trichrome staining and PCR methods. The partial 18S ribosomal RNA gene region was sequenced to identify subtypes of D. fragilis isolates. In addition, demographic features and clinical findings of the cases with D. fragilis were evaluated. In our study, D. fragilis was detected in three (4.05%) of 74 E. vermicularis positive cases by trichrome staining method and in 28 (37.8%) by PCR method. In addition, D. fragilis was detected in one of the 74 vermicularis negative cases (1.35%) by trichrome staining method and in 14 (18.91%) by PCR method. The coexistence of E. vermicularis and D. fragilis was statistically significant (p <0.05). All of the 26 D. fragilis isolates that were analyzed by sequence analysis and were identified as genotype 1. No significant relationship was found between the presence of D. fragilis and clinical findings. There was no statistically significant difference between sex and region and the presence of D. fragilis. Direct microscopic examination of D. fragilis is relatively inefficient, so staining and culture methods are frequently used in routine diagnosis. In recent years, due to advances in molecular methods, these techniques have been used in the diagnosis of parasites. As a result of this study, it was observed that D. fragilis can be frequently associated with E. vermicularis and the presence of D. fragilis in E. vermicularis positive cases should be considered. It is also thought that the use of a second method such as PCR which has high sensitivity and specificity in the diagnosis of D. fragilis, it may be useful in preventing false negative results. The absence of a significant relationship between the clinical findings and D. fragilis supports the idea that there may be pathogen and apathogenic genotypes of the parasite; however, further research is needed. Keywords: Aydin, Dientamoeba fragilis, Enterobius vermicularis, PCR, trichrome.