DIFFERENTIATION OF TRYPANOSOMATID SPECIES BY HYBRIDIZATION TO SELECTED RIBOSOMAL-RNA PROBES

Oligonucleotides with sequences complementary to selected regions of the Trypanosoma cruzi large sub-unit ribosomal RNA (rRNA) were used to specifically detect and quantify T. cruzi and other kinetoplastids. By selecting sequences with varying homologies with Crithida fasciculata, another kinetoplastid for which this sequence was known, probes which hybridized to T. cruzi alone or T. cruzi and T. rangeli, various Leishmania species or C. fasciculata were identified. This identification was possible even though the sequences of the large sub-unit (LSU) rRNA of T. rangeli and Leishmania are not known. None of the probes hybridized with rRNA from mouse or human cell lines, and all could quantitatively detect T. cruzi in tissue culture cells. Probing of replicate membranes with these different oligonucleotides allowed discrimination between these species. The functional application of rRNA-specific probes in diagnosis was demonstrated by identification of unknown trypanosomatids in hemocultures of wild-captured owl and squirrel monkeys using a combinations of oligonucleotides. Therefore, these probes should be useful in diagnosis and identification of T. cruzi and related parasites. © 1993 Academic Press Limited.