Browsing by Author "Stensvold, Christen Rune"

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    Further insight into the genetic diversity of Entamoeba coli and Entamoeba hartmanni
    (WILEY, 2020-01-01) Stensvold, Christen Rune; Ascuna-Durand, Kasandra; Chihi, Amal; Belkessa, Salem; Kurt, Ozgur; El-Badry, Ayman; van der Giezen, Mark; Clark, C. Graham
    Despite the species' wide distribution, studies of the genetic diversity within Entamoeba coli and Entamoeba hartmanni remain limited. In the present study, we provide further insight into the genetic diversity of both species based on analysis of partial nuclear small subunit ribosomal DNA sequences generated from human fecal DNAs from samples collected in Africa, South America, and Europe. Reinforcing the previous recognition that E. coli is a species complex, our data confirm the existence of the two subtypes, ST1 and ST2, previously identified plus, potentially, a new subtype, ST3. While ST1 appears to be genetically quite homogenous, ST2 shows a substantial degree of intrasubtype diversity. ST2 was more common in samples collected outside Europe, whereas ST1 showed no geographical restriction. The potentially novel subtype is represented to date exclusively by sequences from South American and African samples. In contrast to previous reports, our new data also indicate substantial variation in E. hartmanni that could also support the establishment of subtypes within this species. Here, however, no links were identified between subtype and geographical origin.
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    Stool Microbiota Diversity Analysis of Blastocystis-Positive and Blastocystis-Negative Individuals
    (MDPI, 2022-01-01) Stensvold, Christen Rune; Sorland, Brede Aksdal; Berg, Rebecca P. K. D.; Andersen, Lee O'Brien; van der Giezen, Mark; Bowtell, Joanna L.; El-Badry, Ayman A.; Belkessa, Salem; Kurt, Ozgur; Nielsen, Henrik Vedel
    Blastocystis is a unicellular eukaryote found in the gastrointestinal tract of both human and other animal hosts. The clinical significance of colonic Blastocystis colonization remains obscure. In this study, we used metabarcoding and bioinformatics analyses to identify differences in stool microbiota diversity between Blastocystis-positive and Blastocystis-negative individuals (n = 1285). Alpha diversity was significantly higher in Blastocystis carriers. At phylum level, Firmicutes and Bacteroidetes were enriched in carriers, while Proteobacteria were enriched in non-carriers. The genera Prevotella, Faecalibacterium, Flavonifracter, Clostridium, Succinivibrio, and Oscillibacter were enriched in carriers, whereas Escherichia, Bacteroides, Klebsiella, and Pseudomonas were enriched in non-carriers. No difference in beta diversity was observed. Individuals with Blastocystis-positive stools appear to have gut microbiomes associated with eubiosis unlike those with Blastocystis-negative stools, whose gut microbiomes are similar to those associated with dysbiosis. The role of Blastocystis as an indicator organism and potential modulator of the gut microbiota warrants further scrutiny.