Protease Activity in Different Blastocystis Subtypes in Isfahan

Blastocystis is an extracellular and immobile protozoan known as the most common protozoan found in the human gastrointestinal tract and a wide range of animals. Although it takes a long time to identify it, its role in the disease and health of people is controversial. Parasite protease is one of the important factors in eliciting symptoms. Thus, this study investigated protease activity in several subtypes.

Stool samples were collected from 600 patients referred to Isfahan laboratory centers. The samples were examined microscopically and the blastocysts positive samples were cultured in medium. The blastocysts were purified using the ficoll method. PCR and sequencing were performed to identify the subtypes. Gelatin/SDS-PAGE method was used to evaluate protease activity.

A total of 34 samples was positive in culture and PCR. Of these, 18 samples were sequenced, and 4 subtypes 1-3 and 6 were isolated. Subtype 2 was more common. In the Gelatin/ SDS-PAGE method, a large difference in the size of the bands resulting from protease activity was evident in different subtypes. 20 kDa band was observed in subtypes 1-3. In Subtype 6, the band pattern was completely different from other subtypes.

Differences in protease band size were observed in different subtypes, which could probably be the reason for the difference in protease activity and pathogenicity in different subtypes. The present study obtained more reliable results using the ficoll method.