The Comparison of Blastocystis Frequency, by Direct and Culture Methods, among the Health Card Applicants in Isfahan City, Iran, 2017

Blastocystis is currently one of the most common protozoa in the human gastrointestinal tract and a wide range of animals. This protozoan has different shapes and sizes. Its small cystic form may not be detected by microscopic methods. The purpose of the present study was to compare the direct method with culture in detection of Blastocystis parasite among the health card applicants.

Stool samples were collected from 126 people who applied for a health card in Isfahan City, Iran, in year 2017. The samples were examined directly by microscope for the presence of Blastocystis. Then, all samples were cultured in Blastocystis specific medium. After 3-4 days, culture samples were smeared and examined under a microscope.

12 samples (9.5%) in direct method and 23 samples (18.3%) in culture medium were positive for Blastocystis. The sensitivity and specificity of the direct method compared to the culture was 25.00 and 87.32 percent, respectively. Other factors such as sex, age, education, travel, and gastrointestinal symptoms were not associated with Blastocystis infection, but there was a significant relationship between bird retention and Blastocystis infection.

 The results of this study show that the incidence of Blastocystis infection among the health card recipients is similar to that of other people of society; but these individuals are more important in transmitting the infection. Moreover, comparison of direct method with culture for identification of Blastocystis parasites indicates that culture is superior.