Use of recombinant DNA probes for species identification of Old World Leishmania isolates.

Recombinant DNA probes from a genomic Leishmania major library were screened for their potential to distinguish among Old World Leishmania taxa by Southern blot analysis. A probe, pDK10, was selected and tested on a panel of 58 Old World Leishmania strains that had already been typed isoenzymatically; these strains belong to the different species described so far and had been isolated from various hosts and vectors in 14 countries. In the present study, 45 zymodemes were represented. Using the pDK10 probe, we were able to differentiate between the different phenetic complexes. No variations in hybridization patterns were found within these complexes. In addition, there was a good concordance between identification based on DNA hybridization with the pDK10 probe and that based on isoenzyme typing. The probe has been applied in identifying Leishmania strains that were isolated in Tunisia from humans, animals, or insects. Our results show that the application of the pDK10 probe, in combination with a Pst I digestion of Leishmania DNA, could be a possible alternative to isoenzyme analysis for the identification of Leishmania strains.