Identification and differentiation of Cryptosporidium species by capillary electrophoresis single-strand conformation polymorphism.

Cryptosporidium species generally lack distinguishing morphological traits, and consequently, molecular methods are commonly used for parasite identification. Various methods for Cryptosporidium identification have been proposed, each with their advantages and disadvantages. In this study, we show that capillary electrophoresis coupled with single-strand conformation polymorphism (CE-SSCP) is a rapid, simple and cost-effective method for the identification of Cryptosporidium species and genotypes. Species could be readily differentiated based on the SSCP mobility of amplified 18S rRNA gene molecules. Clones that differed by single-nucleotide polymorphisms could be distinguished on CE-SSCP mobility. Profiles of species known to have heterogenic copies of 18S rRNA gene contained multiple peaks. Cloning and sequencing of Cryptosporidium parvum, Cryptosporidium hominis, Cryptosporidium fayeri and Cryptosporidium possum genotype 18S rRNA gene amplicons confirmed that these multiple peaks represented type A and type B 18S rRNA gene copies. CE-SSCP provides a reliable and sensitive analysis for epidemiological studies, environmental detection and diversity screening.