Division of BlastocystisST10 into three new subtypes: ST42‐ST44

Abstract

The Blastocystis subtype ST10 has been recognized to contain a great deal of diversity at the sequence level, potentially indicating the presence of multiple new STs within the clade. However, the data needed to validate these new STs were not available. To help resolve this diversity, full‐length small subunit (SSU) rRNA gene reference sequences were generated using Oxford Nanopore MinION long‐read sequencing from 21 samples representing multiple domestic and wild hosts and geographic regions and covering the sequence diversity previously described using fragments of the SSU rRNA gene. Phylogenetic and pairwise distance analyses were used to compare full‐length sequences of the SSU rRNA gene generated in this study with all other valid STs of Blastocystis. We present data supporting the division of ST10/ST23 cluster into five subtypes, ST10, ST23, and three new subtypes with the proposed ST designations of ST42, ST43, and ST44. As the host range of Blastocystis continues to expand with new subtypes and new hosts being frequently identified, the reference sequences provided in this study will assist in accurate sequence classification and help to clarify the epidemiology of this common intestinal microeukaryote.

Evaluation of the Use of Singleplex and Duplex CerTest VIASURE Real-Time PCR Assays to Detect Common Intestinal Protist Parasites

“…is a frequent protist that colonizes/infects the human gastrointestinal tract. To date, 40 Blastocystis subtypes, including ST1-ST17, ST21, and ST23-ST44, are considered taxonomically valid [44][45][46][47][48]. The VIASURE Blastocystis + D. fragilis assay was able to identify ST1-ST4 (the most frequent STs circulating in humans), in addition to ST5 and ST8.…”

First molecular subtyping and zoonotic significance of Blastocystis sp. in Dromedary (C. dromedarius) and Bactrian (C. bactrianus) camels in Iran: A molecular epidemiology and review of available literature

“…The predominant STs observed are ST10 and ST14. Furthermore, among the 15 zoonotic STs (ST1-ST10, ST12-ST14, ST16, and ST23) of Blastocystis reported thus far (Jiménez et al, 2022;Santin et al, 2024;Shams et al, 2024), nine zoonotic STs (ST1-ST7, ST10, and ST14) have been found in camels.…”

Molecular Identification and Subtype Analysis of Blastocystis sp. Isolates from Wild Mussels (Mytilus edulis) in Northern France

“…The reference tree was constructed with IQ-TREE using the K2P + I + G4 model, chosen to maintain consistency with the substitution model and with 1000 bootstrap replicates [47]. The tree was rooted on the cluster ST15/ST28 showing the earliest emergence within the Blastocystis genus in recent phylogenetic analyses [26][27][28][29]. Placement of sequences was refined with EPA-ng, a tool designed for precise phylogenetic placement [48], and the resulting data were processed and visualized using Gappa [49].…”

“…Based on small subunit (SSU) rDNA gene sequences comparison, this protozoan exhibits a wide intra-genus genetic diversity, with no fewer than 42 so-called subtypes (STs) currently identified as valid, with two of them (ST10 and ST43) divided into two subgroups (ST10a/ST10b and ST43a/ST43b) [24][25][26][27][28][29][30]. Interestingly, more than 90% of the subtyped isolates in humans belong to ST1 and to ST4, likely related to widespread human-tohuman transmission [11,31,32].…”