Prevalence and subtype identification of Blastocystis isolated from human in Shiraz city, southern Iran

Abstract

BackgroundBlastocystis is the most common parasite in humans and animals. Molecular studies based on the small subunit ribosomal RNA gene (SSU-rRNA) have shown that Blastocystis isolates have 17 subtypes and nine of these subtypes have been reported in human. The objective of the present study was to identify the subtype of Blastocystis. isolated from human in Shiraz city, southern Iran. Materials and methodsA cross-sectional study was conducted from March to August 2019. A total of 802 fecal samples from persons who were referred to health centers of Shiraz University of medical sciences were collected and tested by wet mount method to find Blastocystis. Genomic DNA was extracted from the fecal samples to be positive for Blastocystis. SSU-rRNA gene was amplified by the polymerase chain reaction. The amplicons were sequenced and compared with published sequences in GenBank using BLAST system. Phylogenetic analysis was performed using the maximum likelihood method in the MEGA 5.0 software. ResultsThe microscopy method showed that 39 out of the 802 fecal samples were positive to Blastocystis. A 500 bp fragment of SSU-rRNA was amplified from isolates after the PCR. Sequence analysis identified four subtypes (STs) of Blastocystis consisted of ST1 (32.43%), ST2 (24.32%), ST3 (35.14%) and ST7 (8.11%). ConclusionsFour subtypes (STs) of Blastocystis in human was identified in our study and subtype 3 was the most prevalent subtype. The common subtype (ST3) in this study was identical to the reports from other regions of Iran. For identification of the more subtypes of Blastocystis, comprehensive molecular studies with a large number of Blastocystis isolates are suggested.