A Study of The Genetic Variability of Blastocystis hominis Isolates in Hamadan, West of Iran

Abstract

Blastocystis hominis is a common protozoan parasite in the human and many other animals intestine. the parasite pathogenicity is still controversial. A few studies have been conducted on prevalence of B.hominis subtypes in Iran. The results of present study improve our knowledge on B. hominis subtypes in Iran and therefore we can do more investigations on pathogenicity potential of these subtypes in the future. Background:Blastocystis is a common protozoan parasite in mammals, birds, amphibians, reptiles, fish, arthropods, and annelids. This parasite has some subtypes, which pathogenicity status of them still remained controversial. Some of Blastocystis subtypes are potentially pathogenic to human. Objectives: This study has identified the B. hominis subtypes and their prevalence rates in Hamadan. Patients and Methods: During two months of summer 2011, a total number of 250 human fecal samples referred for parasitology examination to Beasat Hospital and a few clinical laboratories of Hamadan city were collected. The samples were examined by direct method and formalin-ether. 41 samples exhibited positive results for B. hominis thereby were cultured in Locke-egg medium. After the growth and in order to genotype identification, B. hominis isolates were amplified by PCR, using seven pairs of sequencestagged site primers. . Results: In this study, three subtypes of B. hominis consisted of one [SB83], two [SB340] and three [SB227] were identified. The most dominant genotype was SB83 with 56.1% frequency. The prevalence rate of genotype SB227 and SB340 were 22% and 7.3%, respectively. Coexistence of genotypes SB83 and SB227 was detected in 14.6% of positive cases. Conclusions: This is the first study in Hamadan on genotyping of B. hominis, which may trigger other epidemiologic and zoonotic studies on different subtypes and hence control clinical manifestations of infection.

Prevalence and Genotype Analysis of Blastocystis hominis in Iran: A Systematic Review and Meta-Analysis

“…There has been less attention to B. hominis in the diagnostic and training field in Iran and clinicians do not believe in pathogenicity and its treatment that may play a role in increasing its prevalence. Result of only three genomic studies that were performed in Iran (36,60,64) are similar to many studies performed in other regions of the world that have reported ST3 as the most common subtype of B. hominis in the world (7% -92%) (78,79). Some researchers have attributed ST3 to urticaria, HIV and cancer (80).…”

“…and limited to some specific areas in the country (36,60,64). We hope that similar investigations will be expanded in the future to collect more useful information to help health policy makers in this region to better understand the prevalence and pattern of the disease.…”