Genetic Diversity of Human Blastocystis Isolates in

There are some genetic differences in Blastocystis that show the existence of species or genotypes. One of these genes that help in identifying Blastocystis is SSUrRNA. The aim of this study was assessment of genetic diver­sity of Blastocystis by PCR with seven pairs of STS primers. This study was done on 511 stool samples collected from patients referred to the health care centers of Khorramabad, Central Iran, in 2012. Ge­nomic DNA was extracted and in order to determine the Blastocystis subtype in contaminated samples, seven pairs of primers STS (subtype specific sequence-tagged site) were used. Out of 511 samples, 33 (6.5%) samples were infected with Blastocystis. Subtype (ST) of 30 samples was identified and three subtypes 2, 3 and 4 were determined. Mix infection was reported 10% which 3.33% of the infection was for the mixture of ST 3 and ST5 and 6.67% was for the mixture of ST 2 and ST 3. The predominant subtype was ST3 that is the main human sub­type. The dominance of ST2 and 5 are important in this study. This superiority has been reported in some of the studies in ST 2 which is different from the studies in other countries, because they have announced priorities of the ST1 and ST6 after ST3.