Identification of Blastocystis sp. subtypes from human using 18s rRNA in Northwest of Iran

Abstract

Abstract Background & aim: Blastocystis sp. is an anaerobic parasite which lives in the digestive system and can be a zoonotic parasite in different hosts. This study was carried out to identify subtypes and to investigate the genetic variation of Blastocystis sp. from human samples in Urmia, Tabriz & Maragheh cities Northwest of Iran. Methods: In the present descriptive-cross sectional study, 300 human stools from January to October 2017 were randomly selected from treatment centers in North West of Iran. Based on microscopic observation, positive samples examined by DNA barcoding methods for detection of Blastocystis sp. subtypes and their sequences were analyzed. Results: of the 300 samples, 22 specimens diagnosed as Blastocystis sp. with the microscopic method. Sixteen apart isolates from the positive cases obtained by the molecular method (PCR) and the sequences of the products were examined. Three types of subtypes including ST1, ST2 and ST3 obtained from these samples. One of the samples after two different sequencings, was reported as both of the ST1 and ST3 subspecies, but re-sequencing of the dominant show ST3. Conclusion: There are various subtypes of this parasite in this area. Due to the nature of the subtypes, the zoonotic cycle of this parasite exists in this region. By identifying and determining the Blastocysts subspecies in different hosts as a zoonotic organism, it is possible to detect genetic migration and parasite transmission. It seems that the parasite subtype pattern can be considered in future studies in relation to clinical manifestations.

Keywords

• Blastocystis sp.
• subtypes
• 18s rRNA
• Northwest
• Iran