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Updated: Jun 24, 2026
Human Blastocyst Biopsy and Vitrification
Published on: July 26, 2019
Molecular epidemiology of human Blastocystis isolates in France
Laetitia Souppart1, Giovanna Sanciu, Amandine Cian
1Inserm, U547, Institut Pasteur de Lille, Université Lille Nord de France, 1 rue du Professeur Calmette, BP 245, 59019, Lille Cedex, France.
Abstract:
Blastocystis sp. is the most common eukaryotic parasite in the intestinal tract of humans. Due to its strong impact in public health, in this study, we determined the frequency of different Blastocystis subtypes in patients in France. We hypothesized on the mode of transmission and tested a possible relationship between the subtype and symptomatic status. We obtained a total of 40 stool samples identified as positive for Blastocystis by microscopic examination of smears. Participants consisted of 25 symptomatic and 15 asymptomatic patients, for whom clinical and parasitological data were collected. For nested-polymerase chain reaction and genotyping, DNA was extracted directly from fecal samples or from fecal cultures. Morphological forms observed in fecal cultures were uncorrelated with symptomatic status. Genotyping using partial small subunit rRNA gene analysis identified a total of 43 Blastocystis isolates corresponding to 37 single infections and three mixed infections by two different subtypes. These 43 isolates belonged to five subtypes (1, 2, 3, 4, and 7) with predominance of subtype 3 (53.5%). Patient symptomatic status was uncorrelated with Blastocystis subtype.
Insights
Blastocystis sp., a common human gut parasite, was studied in France. Subtype 3 was most frequent, but no link was found between Blastocystis subtypes and patient symptoms.
Area of Science:
- Microbiology
- Parasitology
- Public Health
Background:
- Blastocystis sp. is the most prevalent eukaryotic intestinal parasite globally.
- Its public health significance necessitates understanding its epidemiology and transmission.
Purpose of the Study:
- To determine the frequency of different Blastocystis subtypes in a French patient population.
- To investigate potential transmission routes and the relationship between Blastocystis subtypes and symptomatic status.
Main Methods:
- 40 stool samples from Blastocystis-positive patients (25 symptomatic, 15 asymptomatic) were analyzed.
- DNA was extracted from fecal samples/cultures for nested-polymerase chain reaction and genotyping.
- Partial small subunit rRNA gene sequencing was used for subtype identification.
Main Results:
- 43 Blastocystis isolates were identified, comprising 37 single and 3 mixed infections.
- Five subtypes (1, 2, 3, 4, and 7) were detected, with subtype 3 being predominant (53.5%).
- No correlation was found between Blastocystis subtype and the symptomatic status of patients.
Conclusions:
- Subtype 3 is the most common Blastocystis subtype in the studied French population.
- The study did not establish a link between specific Blastocystis subtypes and the presence of symptoms.
