Genotyping and subtyping of blastocystis sp., which is seen in humans and animals

Blastocystis sp., isolated from human beings and animals, has 17 subspecies that can be detected up to day. Nine of these subspecies can be seen in humans and they are called Blastocystis hominis. Infection sources and pathogenesis of Blastocystis hominis was one of the most debated topics. As a result of the conducted studies, Blastocystis hominis is considered to be a pathogenic factor. Although there is consensus on the fact that it is associated with diseases such as gastrointestinal (GI) complaints and urticaria, there are still debates on the differentiation of factors that affect the pathogenesis and apoptosis. It is stated today that subtypes and morphological forms may be factors affecting the pathogenicity of Blastocystis hominis. The study included 51 positive stool samples collected from patients admitted to the Gastroenterology, Dermatology, Oncology polyclinics of the Dicle University Faculty of Medicine and from control groups, 18 stool samples from healthy individuals with no complaints, and 27 positive animal specimens in regards to Blastocystis hominis consisting of double-claw, single-claw and poultry groups. The samples included in the study were evaluated by Native-Lugol and trichrome staining method. Positive samples were evaluated by the culture method. The subtypes of the samples which were positive in culture were determined by the PCR method. Sequence-Tagged Site (STS) primers were used for the detection of 9 subtypes capable of infecting in-house during PCR. All specimens positive for direct microscopic examination were also detected as positive by the Jones medium culture method too. The culture method was evaluated as a more reliable method of identifying animal stool specimens with numerous cellular structures and artefacts. ST3 was identified as the most common subtype in our research. The frequency of sighting following ST3 was determined as ST1, ST2, ST7, ST6 and ST5 respectively. In this study, ST5 and ST6 were detected in sheep for the first time in our country. In our study, no subtypes could be detected in 12 patients with PCR positive Blastocystis hominis general primers. This provided us the idea that subtypes infecting humans are more than 9 and we could detect other subspecies in the future studies conducted with molecular sequence analysis.