Genotypes of Blastocystis sp. among elderly health checkup people in South Korea with a questionnaire on risk factors

• Published in: Parasitology research (1987) Vol. 120; no. 9; pp. 3297 - 3306
• Main Authors: Chang, Taehee, Jung, Bong-Kwang, Shin, Hyejoo, Hong, Sooji, Ryoo, Seungwan, Lee, Jeonggyu, Han, Seihee, Park, Sun Min, Rhee, Min-Suk, Kimm, Heejin, Jee, Sun Ha, Chai, Jong-Yil
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01-09-2021; Springer; Springer Nature B.V
• Subjects: Aged; Bacterial infections; Biomedical and Life Sciences; Biomedicine; Blastocystis; Drinking water; Genetic aspects; Genotype; Genotypes; Immunology; Medical Microbiology; Microbiology; Parasites; Physical fitness; Physical fitness for the aged; Protozoology - Original Paper; Public health; Questionnaires; Risk factors; RNA; rRNA; Statistical analysis; Surveys; Vegetables; South Korea; South Korea; Molecular subtyping; sp; Risk factor
• ISSN: 0932-0113; 1432-1955
• DOI: 10.1007/s00436-021-07274-w

Blastocystis
sp. is a common zoonotic intestinal parasite of humans and animals, and has been classified into at least 17 distinct subtypes. Despite its potential impact on public health, the prevalence and subtype distribution of
Blastocystis
sp. have seldom been the study subject in South Korea. To determine the prevalence and subtype distribution of
Blastocystis
sp. and to obtain information on risk factors, we performed a cross-sectional study targeting elderly health checkup people, who visited Seoul Western Branch of the Korea Association of Health Promotion (KAHP) in October 2019. Stool samples were collected from 293 participants consisting of 128 males and 165 females with a mean age of 64.7 years (from 50 to 88 years) with a questionnaire on potential risk factors. All the samples were tested by PCR targeting the SSU rRNA gene of
Blastocystis
sp., and nucleotide sequences of positive samples were used to identify the subtypes. The overall prevalence of
Blastocystis
sp. was 9.2% (27/293). Among the positive samples, subtype 3 was predominant (59%; 16/27), followed by subtype 1 (41%; 11/27). No other subtypes were detected. In the univariable analysis, the age, sex, presence of digestive symptoms, source of drinking water, and history of drug intake were not significantly associated with
Blastocystis
sp. infection. Two parameters, including the
Enterococcus hirae
bacterial infection and the frequency of intake of cooked or boiled vegetables less than twice a week, showed statistical significance. However, the multivariable regression analysis revealed that only the latter parameter was statistically significant. The results suggested that subtypes 3 and 1 are the 2 major genotypes of
Blastocystis
sp. among elderly people in South Korea, and low frequency of consuming cooked or boiled vegetables is a potential risk factor.