Discrimination of Leishmania braziliensis variants by kDNA signatures produced by LSSP-PCR.

The conventional methods for identification and typing of Leishmania species depend on previous culture isolation of the parasites. Not infrequently, culture is unsuccessful and may result in misrepresentation of the heterogeneity of the original isolate. Thus, more reliable and precise identification of genotypes of Leishmania spp. is important for a better clinical and epidemiological understanding of the disease. We evaluated the potential of LSSP-PCR targeting kDNA minicircles in discriminating different variants of the parasite with the use of clinical samples directly or cultivated parasites. The 1st step of this procedure consists of the amplification of the minicircles by conventional PCR; the 2nd step is low-stringency amplification of the minicircles previously amplified, with the use of 1 of the primers. Although LSSP-PCR produced complex and distinct kDNA signatures for isolates representing different species, further experiments demonstrated that the approach had the potential for discriminating intraspecific variants of L. braziliensis. Thus, the generated profiles were too variable to be useful as markers for species identification. Moreover, we demonstrated that the approach can be directly applied to clinical samples. In conclusion, LSSP-PCR targeting kDNA minicircles produces profiles that reflect polymorphisms of the predominant classes of minicircles, and can be useful for studies aimed at discriminating Leishmania braziliensis genotypes without the need for previous cultivation of the parasite.