Abstract
BackgroundBlastocystis is a human gut symbiont of yet undefined clinical significance. In a set of faecal samples collected from asymptomatic children of six distant populations, we first assessed the community profiles of protist 18S rDNA and then characterized Blastocystis subtypes and tested Blastocystis association with the faecal bacteriome community.MethodsStool samples were collected from 244 children and young persons (mean age 11.3 years, interquartile range 8.1–13.7) of six countries (Azerbaijan 51 subjects, Czechia 52, Jordan 40, Nigeria 27, Sudan 59 and Tanzania 15). The subjects showed no symptoms of infection. Amplicon profiling of the 18S rDNA was used for verification that Blastocystis was the most frequent protist, whereas specific real-time PCR showed its prevalence and quantity, and massive parallel amplicon sequencing defined the Blastocystis subtypes. The relation between Blastocystis and the stool bacteriome community was characterized using 16S rDNA profiling.ResultsBlastocystis was detected by specific PCR in 36% (88/244) stool samples and was the most often observed faecal protist. Children from Czechia and Jordan had significantly lower prevalence than children from the remaining countries. The most frequent subtype was ST3 (49%, 40/81 sequenced samples), followed by ST1 (36%) and ST2 (25%). Co-infection with two different subtypes was noted in 12% samples. The faecal bacteriome had higher richness in Blastocystis-positive samples, and Blastocystis was associated with significantly different community composition regardless of the country (p < 0.001 in constrained redundancy analysis). Several taxa differed with Blastocystis positivity or quantity: two genera of Ruminococcaceae were more abundant, while Bifidobacterium, Veillonella, Lactobacillus and several other genera were undrerrepresented.ConclusionsAsymptomatic children frequently carry Blastocystis, and co-infection with multiple distinct subtypes is not exceptional. Prevalence and quantity of the organism clearly differ among populations. Blastocystis is linked to both faecal bacteriome diversity and its composition.Graphical
Highlights
Blastocystis is a human gut symbiont of yet undefined clinical significance
The molecular testing consisted of four steps. (i) First, the total parasitome was profiled by multiplex massively parallel amplicon sequencing of several regions of the 18S rDNA gene; this yielded a rough overview of unicellular parasites present in the samples. (ii) Blastocystis sp., having been identified as the by far most prevalent parasite, was tested and quantified using specific real-time PCR. (iii) Blastocystispositive samples were classified into sequence types using massively parallel amplicon sequencing of an informative portion of the 18S rDNA. (iv) associations were explored between bacteriome 16S rDNA profiles and positivity or quantity of Blastocystis
Subjects and their samples One stool sample was analysed per subject; the subjects were children and young persons from six countries participating in a case–control study on the microbiome in recently diagnosed type 1 diabetes and matched controls [12] and in a study in Czech children with type 1 diabetes [14]
Summary
Blastocystis is a human gut symbiont of yet undefined clinical significance. The human gut microbiome consists of the microbial community (bacteria, archaea, viruses, fungi and protists), encompassing their theatre of activity The prime representative of the gut protozoa is Blastocystis sp., an anaerobic Stramenopile, a protist with a complicated life cycle and multifaceted morphology [2]. Is believed to be the most prevalent human gut eukaryote [3]. It is a symbiont: either a commensal [4] or a parasite whose clinical relevance is yet to be defined. Of the 22 subtypes defined as of 2018 [8], 10 were found in humans, with ST3 or ST4 being most prevalent, followed by ST1 and ST2. The distribution of subtypes varies substantially among continents and countries—most prominently, the ST4 is found commonly in Europe but is rare elsewhere [9]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
