{Reference Type}: Journal Article {Title}: Molecular epidemiology and subtyping of Blastocystis sp. and its subtypes in celiac patients; a case control study. {Author}: Soleimani Jevinani S;Mohammad Rahimi H;Asri N;Rostami-Nejad M;Ahmadipour S;Mirjalali H; {Journal}: Microb Pathog {Volume}: 179 {Issue}: 0 {Year}: Jun 2023 22 {Factor}: 3.848 {DOI}: 10.1016/j.micpath.2023.106086 {Abstract}: Blastocystis sp. is a common intestinal protist, reported from symptomatic and asymptomatic subjects. Blastocystis sp. has been reported from a broad spectrum of gastrointestinal disorders. Celiac disease (CD) is an autoimmune disorder of the small intestine, which leads to the lack of tolerance against gluten. Long-term following of gluten-free diet in CD patients decreases the gut microbiota restoration and probably decreases the chance of Blastocystis sp. colonization. The current study aimed to investigate the prevalence of Blastocystis sp. and its subtypes in CD patients in comparison to healthy subjects. Stool samples were collected from 238 participants including 92 confirmed CD patients and 146 healthy subjects. Upon DNA extraction, the presence of Blastocystis sp. was evaluated using amplification of discriminative regions of the small ribosomal RNA (ssu rRNA) gene. To characterize subtypes and alleles, amplified fragments were sequenced. Phylogenetic trees were constructed to visualize subtype correlation. Our findings showed that 21% (50) of samples including 16.3% (15/92) and 23.97% (35/146) were positive for Blastocystis sp. in CD patients and healthy controls, respectively. Except family relationship, other variables were not statistical correlated with the presence of Blastocystis sp.. Totally, 25 samples were successfully sequenced. Accordingly, ST1, ST2, and ST3 were characterized in 8 (32%), 9 (36%), and 8 (32%) of samples, respectively. Allele discrimination showed that all ST1 were allele 4; alleles 11, 9, and 12 were retrieved from ST2, and alleles 34, 36, and 38 were observed in ST3. The relationship between colonization of Blastocystis sp. and alteration in the gut microbiota composition is indeterminate, however, this hypothesis that following gluten-free diet in CD patients may affect the colonization of Blastocystis sp. via alteration in the gut microbiota composition could be interesting for further investigations.