Ann Clin Microbiol.  2023 Mar;26(1):11-17. 10.5145/ACM.2023.26.1.2.

Epidemiology and subtype distribution of Blastocystis among asymptomatic volunteers in Korea: a multicenter study

• Kim SH
• Byun JH
• Oh Y
• Liu C
• Bae MH
• Won EJ

• KMID: 2540714
• DOI: http://doi.org/10.5145/ACM.2023.26.1.2

Abstract

Background
Blastocystis is a genus of intestinal, anaerobic protozoan parasites that can be isolated from humans, animals, and the environment. We aimed to determine the distribution of Blastocystis and subtypes (STs) using stool samples obtained from healthy volunteers at collection centers in South Korea.
Methods
A total of 478 stool samples from volunteers were collected at five collection centers throughout South Korea. The presence of Blastocystis was determined using PCR based on the small subunit (SSU) rRNA gene, and Blastocystis STs were confirmed through sequencing of the SSU rRNA gene.
Results
Molecular analysis revealed the presence of Blastocystis in 27 (5.6%) of the enrolled participants. Two STs were identified: ST3 (66.7%) and ST1 (33.3%). The positive rates of Blastocystis varied by geographical region, ranging from 1.2%–12.0%. ST3 was the predominant subtype in all centers except one, where only ST1 was isolated. Phylogenic analysis showed clustering based on ST, but no significant differences were found among the regions. There was no association between Blastocystis colonization and either age or sex of the participants.
Conclusions
The results of this multicenter study demonstrated colonization by Blastocystis, mainly ST3, in the gastrointestinal tracts of asymptomatic individuals in South Korea.

Keyword

Blastocystis; Healthy control; South Korea; Subtype

Figure

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  Fig. 1. Phylogenetic analysis of the sequences of Blastocystis small subunit rDNA in this study. A phylogenetic tree was conducted using the unweighted pair group method with arithmetic mean clustering with 1,000 bootstrap replications using Geneious Prime (Biomatters Ltd, Auckland, New Zealand).

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