Molecular characterization and subtyping of Blastocystis in urticarial patients in Turkey

Objective: To investigate Blastocystis’ etiologic role and association with gastrointestinal symptomatology in acute and chronic urticaria patients and to identify Blastocystis subtypes responsible for urticaria. Methods: The study included urticaria patients and healthy individuals that presented to our polyclinic between June 2015 and May 2017. The participants were assigned into Group栺(137 patients), subdivided into acute(72) and chronic urticaria patients(65), and Group栻(129 control individuals). Blastocystis presence was investigated by native-Lugol examination, trichrome staining, PCR using sequence tagged site primers, and DNA sequencing analysis. The phylogenetic tree was constructed. Results: The native-Lugol and trichrome staining methods revealed that 16 patients(16/133, 12.0%) had Blastocystis-positive stool samples, of which seven samples(7/133, 5.3%) belonged acute and nine(9/133, 6.8%) to chronic urticaria patients. Concerning Blastocystis subtypes, of the acute urticaria patients, three had subtype 1(ST1), one had ST2, and three had ST3. Of the chronic urticaria patients, one had ST1 and eight had ST3. Blastocystis positivity was detected in two control individuals(2/123, 1.6%), both being ST3. All subtypes identified by PCR were confirmed by the sequencing analysis. The acute and chronic urticaria groups showed no statistically significant differences for Blastocystis positivity(P=0.60) and subtype distribution(P=0.15). A statistically significant difference was found between the urticaria patients and the controls for Blastocystis positivity(P<0.01), but not for subtype distribution(P=0.67) or for Blastocystis presence and gastrointestinal complaints. Conclusions: This study on Blastocystis subtype distribution among Turkish urticaria patients showed results consistent with the literature. It was concluded that Blastocystis should be kept in mind in patients with urticaria.