Wide genetic variations at 18S ribosomal RNA locus of Cyclospora cayetanensis isolated from Egyptian patients using high resolution melting curve

Abstract

A variable clinical picture of cyclosporiasis including gastrointestinal tract (GIT) symptomatic or asymptomatic beside extraintestinal consequences suggests a possibility of heterogenicity of Cyclospora cayetanensis. The present work aimed to explore the possibility of genetic variation of C. cayetanensis using high-resolution melting (HRM) curve of polymerase chain reaction (PCR) amplified 18S rRNA genes. DNAs extracted from the stool samples of 70 cyclosporiasis patients were amplified and scanned by PCR/HRM curve. The results showed that there are four different genotypic profiles of C. cayetanensis with presence of mixed ones. Although Tm of all profiles was within the same range, they were discerned by plotting of the temperature-shifted florescence difference between normalized melting curves (dF/dT). Genotypic profile I was found alone in 40 % of patients and mixed with genotypic profile II and/or III in 25.7 % of patients, followed by genotypic profile II in 14.3 % then genotypic profile III and IV (10 % each). A significant relation was found between genotypic profiles and GIT symptomatic status as profile I and profile II were mostly detected in patients with acute GIT symptoms without or with chronic illness, respectively, while profile IV cases only were GIT asymptomatic. Statistical significance relations between genotypic profiles and age, gender, residence and oocyst shape index were determined. In conclusion, PCR/HRM proved a wide variation on C. cayetanensis genes that could be reflected on its pathogenic effects and explaining the variability of the clinical manifestations presented by cyclosporiasis patients.

Single-strand conformation polymorphism-based genetic characterization of the <i>Cyclospora cayetanensis</i> strains collected from different provinces in Turkey

“…In this study, SSCP was performed differently as it involved a two-step nested PCR using the 18S rRNA gene, compared with those performed in other studies, and a minor genetic difference was identified among the strains obtained in 4 provinces in Turkey. In 2016, Hussein et al [22] reported that Cyclospora infections have a clinical picture that can change from being symptomatic to being asymptomatic. They claimed that the possible reason behind this variable clinical picture is the genetic heterogeneity of C. cayetanensis.…”