Subtype identification of Blastocystis spp. isolated from patients in a major hospital in northeastern Thailand

Abstract

The present study is aimed to identify the prevalence of Blastocystis subtypes isolated from patients in a major hospital in northeastern Thailand. A total of 562 stool samples were examined by culture technique, and 56 Blastocystis-positive samples were analyzed further by the combination of restriction fragment length polymorphism (RFLP) followed by polymerase chain reaction with sequence-tagged site primers (PCR-STS). By RFLP profiles, Blastocystis genotypes were categorized into four groups: group A (12, 21.4%), group B (32, 57.1%), group C (10, 17.9%), and group D (2, 3.6%). By PCR-STS, only four subtypes were identified. All 12 (21.4%) isolates in group A were identified as subtype 1. Similarly, all 32 (57.1%) isolates in group B were subtype 3. In group C, 10 (17.9%) samples were all subtype 7, and two samples (3.6%) in group D were both subtype 6. Of 56 Blastocystis-positive patients, 31 (55.4%) were asymptomatic and 22 (39.4%) have gastrointestinal symptoms. No significant association was observed between the Blastocystis subtypes and the clinical features. Among the Blastocystis-positive patients, the most characteristic stool samples were loose (78.6%) and soft (17.9%). In conclusion, the most common Blastocystis spp. in northeastern Thailand was subtype 3 followed by subtype 1. Relatively minor subtypes, subtype 6 and subtype 7 which are considered as avian subtypes, were found for the first time in humans in Thailand.

Genetic diversity and pathogenicity of Blastocystis

“…In numerous other investigations there was no association between Blastocystis subtypes and gastrointestinal symptoms [31,51,52]. They identified ST3 as the most frequent subtype in both groups (symptomatic and asymptomatic), but did not observe a significant relationship between this subtype and gastrointestinal symptoms.…”

Molecular Epidemiology of Blastocystis in Lebanon and Correlation between Subtype 1 and Gastrointestinal Symptoms

“…30 However, patient symptomatic status was uncorrelated with Blastocystis ST and symptoms in the context of several other epidemiological studies. 16,21,31,32 To our knowledge, this is the first investigation of prevalence and molecular epidemiology of Blastocystis in Lebanon. In this country, the prevalence of this parasite would be high with predominance of ST3, ST2, and ST1 isolates.…”

The Prevalence of Blastocystis hominis and Other Protozoan Parasites in Soldiers Returning from Peacekeeping Missions

“…1 It is currently the predominant parasite found in human stool samples, with a higher prevalence in developing countries (50-60%) than developed countries (about 10% or less). 1,2 Highly polymorphic and consisting of many morphological forms, including vacuolar, non-vacuolar, granular, amoeboid, and cyst forms, B. hominis can be transmitted as a cyst by the fecal-oral route, particularly in poor hygienic conditions. 1,3 It can be found both in immunocompetent and immunosuppressed individuals; for example, Abdel-Hameed and Hassanin 4 found this parasite in 73.1% of immunocompetent patients and 26.9% of immunocompromised patients.…”