Comprehensive Study of Phenotypic and Growth Rate Features of Blastocystis Subtypes 13 and 6 in Symptomatic and Asymptomatic Subjects

Background: The present study aimed to assess the grouping of subtypes 13 and 6 of Blastocystis according to the size and generation time of the parasite among the symptomatic and asymptomatic subjects. #xD; Methods: Blastocystis subtypes13 and 6 isolated from symptomatic and asymptomatic subjects and were cultivated in DMEM medium. In order to assess inter and intrasubtype variation in size, all the isolates were measured using morphometric criteria. Generation time was calculated using approximately 1 #xD7;104 Blastocystis, which were cultivated in DMEM, every 24h for 4 days. #xD; Results: All subtypes had 5 to 185 #x3BC;m diameter range. The smallest size was attributed to ST1, followed by ST6 and ST2. ST3 showed the most variable size and phenotypes compared with the other three subtypes. Furthermore, amoeboid forms and parasite clumping were only seen in ST3S (symptomatic subjects). Generation time analysis showed that the number of ST1 isolated from symptomatic and asymptomatic subjects peaked higher than the other subtypes. #xD; Conclusion: This is the first study discussing interintrasize, phenotype and generation time variations among 4 common subtypes of Blastocystis. Accordingly, ST3 was largest subtype and showed most diversities in both size and phenotype, while ST1 was smallest subtype with lowest intrasubtype variation.