Frequency and Subtypes of Blastocystis in Patients with Diarrhea in Van, Türkiye 2022–2023

Meryem  Gümüş; Selahattin  Aydemir; Zeynep Taş  Cengiz; Hasan  Yılmaz

doi:10.18502/ijpa.v21i1.21634

Meryem Gümüş Department of Parasitology, Faculty of Medicine, Van Yüzüncü Yıl University, Van, Türkiye
Selahattin Aydemir Department of Parasitology, Faculty of Medicine, Van Yüzüncü Yıl University, Van, Türkiye
Zeynep Taş Cengiz Department of Parasitology, Faculty of Medicine, Van Yüzüncü Yıl University, Van, Türkiye
Hasan Yılmaz Department of Parasitology, Faculty of Medicine, Van Yüzüncü Yıl University, Van, Türkiye

DOI: https://doi.org/10.18502/ijpa.v21i1.21634

Keywords: Blastocystosis; Diarrhea; Microscopy; Subtype1; Türkiye

Abstract

Background: We sought to determine how often Blastocystis. occurs and which subtypes predominate in patients suffering from diarrhea in Van, Türkiye.

Methods: We enrolled 200 volunteers—100 with diarrhea and 100 healthy controls—and examined their stool samples both by light microscopy and by PCR amplification of the 18S SSU rRNA gene. DNA sequences from 14 positive PCR amplicons were analyzed for the 18S SSU rDNA gene, and the subtypes were identified by sequence analysis of the PCR amplicons.

Results: Blastocystis was identified in 20 of 100 diarrheal patients (20%) and in 16 of 100 controls (16%). Among patients, the highest carriage rate was seen in females (21.6%), whereas in the control group it was males who showed the greatest prevalence (20.7%). When stratified by age, individuals aged 11–18 years exhibited the highest positivity: 40% in the patient cohort and 21.4% among controls. No significant differences emerged between patient and control groups with respect to age or sex overall, although the comparison of under-18s (23%) versus those 19 and older (10.3%) reached statistical significance (P = 0.013). Statistical analysis did not reveal any link between Blastocystis carriage and gastrointestinal symptoms. Sequencing of positive diarrheal samples showed that subtype 1 (ST1) accounted for 71.4% and subtype 2 (ST2) for 28.6% of cases.

Conclusion: The dominance of ST1 in diarrheal patients supports the subtype-pathogenicity relationship; however, further studies involving a large number of symptomatic and asymptomatic individuals are required to elucidate this relationship more precisely.