Detection and identification of human pathogenic Leishmania and Trypanosoma species by hybridization of PCR-amplified mini-exon repeats.

A single pair of PCR primers within a conserved region of the mini-exon repeat was used to amplify the repeats from 10 species of pathogenic Leishmania belonging to four major clinical groups and also from three species of Trypanosoma. Oligonucleotide hybridization probes for the detection and identification of the PCR-amplified repeats were constructed from alignments of mini-exon intron and intergenic sequences. The probes generated from mini-exon intergenic regions of the L. (V.) braziliensis, L. (L.) donovani, and L. (L.) mexicana species hybridized specifically to their cognate groups without discriminating between the species within the groups. The probes for L. (L.) major and L. (L.) aethiopica were species-specific, while the L. (L.) tropica probe also hybridized with the L. (L.) aethiopica mini-exon repeat. The mini-exon intron-derived probes for T. cruzi, T. rangeli, and T. brucei were species-specific. This method involving the detection of specific PCR-amplified products produced using a single primer set represents a novel sensitive and specific assay for multiple trypanosomatid species and groups.