RAPID IDENTIFICATION OF CAUSATIVE SPECIES IN PATIENTS WITH OLD-WORLD LEISHMANIASIS

Conventional methods for the identification of species of Leishmania p arasite causing infections have limitations, By using a DNA-based alte rnative, the present study tries to develop a new tool for this purpos e, Thirty-three patients living in Marseilles (in the south of France) were suffering from visceral or cutaneous leishmaniasis, DNA of the p arasite in clinical samples (bone marrow, peripheral blood, or skin) f rom these patients were amplified by PCR and were directly sequenced, The sequences observed were compared to these of 30 strains of the gen us causing Old World leishmaniasis collected in Europe, Africa, or Asi a, In the analysis of the sequences of the strains, two different sequ ence patterns for Leishmania infantum, one sequence for Leishmania don ovani, one sequence for Leishmania major, two sequences for Leishmania tropica, and one sequence for Leishmania aethiopica were obtained, Fo ur sequences were observed among the strains from the patients: one wa s similar to the sequence fbr the L. major strains, two were identical to the sequences for the L. infantum strains, and the last sequence w as not observed within the strains but had a high degree of homology w ith the sequences of the L. infantum and L. donovani strains, The L. i nfantum strains from all immunocompetent patients had the same sequenc e, The L. infantum strains from immunodeficient patients suffering fro m visceral leishmaniasis had three different sequences, This fact migh t signify that some variants of L. infantum acquire pathogenicity excl usively in immunocompromised patients, To dispense with the sequencing step, a restriction assay with HaeIII was used, Some restriction patt erns might support genetic exchanges in members of the genus Leishmani a.