Identification of Mexican Leishmania species by analysis of PCR amplified DNA.

Leishmania parasites isolated into culture from patients with LCL or DCL from four different Mexican states were characterised using polymerase chain reaction (PCR), hybridisation with specific probes, and isoenzymes. PCR of the parasites showed that 10 of 11 of those isolates were members of the mexicana complex. This was confirmed in seven cases by isoenzymes. Restriction enzyme digests of PCR products of Mexican isolates showed the isolates to be different from the L.(L.) mexicana reference strain BEL21. Two (C2 and AM) of the isolates were shown to be a possible mixed infection between mexicana and braziliensis complex members. With a second set of samples from different patients from Campeche state, PCR of 14 biopsies indicated the presence of braziliensis complex members in six of the samples. The results showed that most of our isolates of Leishmania which come from the states of Tabasco and Veracruz are members of the Leishmania mexicana complex, but they seem to be different from the L.(L.) mexicana BEL21 reference strain. By hybridisation most of the biopsies (seven out of 14) from Campeche belong to the L. braziliensis complex and two out of 14 to L. mexicana complex and three out of 14 hybridised with both complexes, and two biopsies were negative. In Campeche, which is very close to Tabasco state and has border with Guatemala, we found members of the L. mexicana and L. braziliensis complexes.