Molecular Epidemiology of Blastocystis spp. Isolates in Bandar Abbas, South of Iran

Background and Aim: Blastocystis spp. is an anaerobic, single-celled intestinal parasite with global prevalence that is found in the lower digestive tract of humans and many animals, such as numerous types of vertebrates. To date, 17 genotypes have been identified. Nine of these genotypes are common in humans. Organism is found in both healthy and compromised individuals, hence its pathogenicity is controversial. The aim of this study was to investigate the frequency of Blastocystis spp. genotypes in Bandar Abbas, Iran during 2022. Materials and Methods: Totally, 378 stool samples were collected from hospitals and health centers of Bandar Abbas, Hormozgan province, Iran. Stool samples examined by direct and formalin ethyl acetate (concentration) methods. Positive samples for Blastocystis spp. isolated and DNA extraction was done. All extracted DNA specimens analyzed by nanoDrop to ensure about quantity and quality. The PCR technique was used to identify parasite genotypes and all samples were sequenced for genotype confirmation. Results: Finally 14 samples detected as positive microscopically and 8 samples confirmed by PCR. Identified isolated genotypes were 4 samples ST1 (50%), 3 ST3 (37.5%), and one ST2 (12.5%). All negative and positive samples analyzed 3 times to confirm accuracy.  Conclusion: Blastocystis sp. is the most common protozoan parasite of the human intestine, which despite the studies, there are many uncertainties about its pathogenicity.  The current study was designed and carried out during the Covid-19 pandemic and lower positive patients may be related to severe hygiene considerations and consumption of various antibiotics amongst the population.