Detection of blastocystis positivity and subtypes in diarrhoeal cases admitted to Aydin Adnan Menderes University Faculty of Medicine parasitology laboratory

Objective: The aim of this study is to detect Blastocystis and subtypes in diarrhoeal cases sent from different clinics to Aydin Adnan Menderes University, Parasitology Laboratory. Material and Methods: A total of 200 stool samples with diarrhea were investigated by direct microscopy (DM) and polymerase chain reaction (PCR). Blastocystis subtypes were identified based on partial sequences of the ribosomal RNA small subunit (SSU rRNA) gene. Allele sequences have also been determined in Blastocystis subtypes. Demographic features and clinical findings of the cases were compared in terms of the presence of Blastocystis. In addition, the relationship between Blastocystis subtypes and clinical findings was evaluated. Results: Blastocystis was detected in 31 (15.5%) of 200 diarrheal stool samples by DM and in 35 (17.5%) by PCR method. According to the sequence analysis, Blastocystis subtype was determined in 33 samples and its distribution was found as ST1 (n:10, 30.3%), ST2 (n:4, 12.1%) and ST3 (n:19, 57.6%). Allele sequences of the subtypes were determined separately; allele 4 (10/10) in ST1, allele 11 (2/4) and allele 12 (2/4) in ST2, allele 34 (14/19), 36 (4/19) and 38 (1/19) in ST3. The symptoms of dyspepsia and nausea-vomiting were found to be statistically significant for positive Blastocystis infected cases (p=0,0025, p=0,0498). In addition, a significant relationship was found between ST3 of Blastocystis subtypes and dyspepsia (p=0,0039). Conclusion: In conclusion, the PCR method used in the detection of Blastocystis in diarrheal cases was found to be more sensitive than the DM method. Due to the relationship between Blastocystis subtypes and symptoms, it was concluded that more detailed studies are needed. Keywords: Aydin, clinical findings, Blastocystis, diarrhea, subtype