High occurrence of Blastocystis sp. subtype 3 in individuals referred to medical laboratories in Kermanshah, Iran

AIM: The current study investigated the prevalence and genotypes of Blastocystis sp. in individuals who referred to medical laboratories in Kermanshah, Iran. BACKGROUND: Blastocystis sp. is a common intestinal protozoan found in humans and a wide range of animals, and it is involved in the development of gastrointestinal disorders. METHODS: A total of 950 stool samples were examined using the standard formalin-ether concentration technique. All specimens were cultured in Robinson xenic medium. Subsequently, DNA extraction and PCR amplification of subtype specific sequence-tagged site (STS) were conducted. RESULTS: Microscopic examination showed that 86 out of 950 samples (9.05%) were infected with Blastocystis sp. Subsequently, 33 of 86 positive samples were cultured and molecularly confirmed by conventional PCR, indicating six subtypes (ST1-ST6). Of note, ST3 (45.0%) was the predominant subtype, followed by ST1 (15.15%) and ST5 (12%). CONCLUSION: Based on the current findings, ST3 was the most frequent subtype among all positive samples. Having a better understanding of Blastocystis sp. subtype distribution and risk factors would lead to improved preventive measures.