Identification and validation of novel Blastocystis subtype ST41 in a Colombian patient undergoing colorectal cancer screening

Abstract

Blastocystis sp. is among the most frequent intestinal protists identified in humans globally. However, characterization of Blastocystis subtype diversity in humans is ongoing. We report here the identification of novel Blastocystis subtype ST41 in a Colombian patient undergoing colorectal cancer screening involving colonoscopy and fecal testing (microscopy, culture, PCR). The full‐length ssu rRNA gene sequence of the protist was generated using MinION long‐read sequencing technology. The validity of the novel subtype was confirmed via phylogenetic and pairwise distance analyses of the full‐length ST41 sequence and all other valid subtypes. The study provides reference material essential for conducting subsequent experimental studies.

Division of BlastocystisST10 into three new subtypes: ST42‐ST44

“…Sequence variation within the first 600 bp (barcoding region) of the SSU rRNA gene is low for subtypes within this clade. This situation is not unique to the ST10/ST23/ ST42-ST44 clade and has been similarly noted as problematic for classifying sequences within the ST14/ST24/ ST25 clade, the ST5/ST12 clade, and the ST17/ST41 clade (Hernández-Castro, Dashti, et al, 2023;Hernández-Castro, Maloney, et al, 2023;. Thus, if subtype designations are being made using primers such as the so-called barcoding primers (Scicluna et al, 2006) that cover the first 600 bp region of the SSU rRNA gene or the commonly used qPCR primers (Poirier et al, 2011) that cover a 300 bp region within the barcoding region, definitive ST assignments may not be possible.…”

“…Surveys of Blastocystis subtype diversity in new hosts and regions of the world continue to expand the host range of previously identified subtypes and identify new subtypes (Baek et al, 2022;Hernández-Castro, Dashti, et al, 2023;Hernández-Castro, Maloney, et al, 2023;Jinatham et al, 2021;Nguyen et al, 2023;Stensvold et al, 2023;Yu et al, 2023). As interest in Blastocystis grows, the ability to correctly identify and distinguish sequences is more important than ever.…”

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.…”

Prevalence of Blastocystis sp. in Morocco: Comparative assessment of three diagnostic methods and characterization of parasite forms in Jones’ culture medium

“…remains a subject of debate, further complicated by the discovery of new subtypes. Currently, 40 subtypes (STs): ST1 to ST17, ST21, and ST23 to ST44 have been identified [ 18 , 27 , 48 ], with 16 detected in humans, including ST1 to ST10, ST12, ST14, ST16, ST23, ST35, and ST41 [ 18 , 23 , 27 , 34 ]. Other subtypes, not designated by numbers were found in cold-blooded vertebrates.…”

“…Similar genetic diversity, not designated by numbers, has been identified in cold-blooded vertebrates. Subtypes and other genetic variants were all identified by comparing 18S rRNA gene sequences [ 18 , 27 , 48 ].…”