Differentiation in a Single-Tube PCR between Leishmania mexicana and Leishmania braziliensis in Clinical Samples

Abstract

Aim: To assess the usefulness of a single-tube PCR end point for differentiating between Leishmania and Viannia subgenera in clinical samples of cutaneous leishmaniasis. Methodology: Impression smears of 65 patients from Campeche State, Mexico with leishmaniasis-like lesions were analyzed by conventional Giemsa staining and a new simple PCR end point with primers named LU-5A designed by [Harris et al.1998] and LME (designed for this study and based on a mini-exon of L.(L) mexicana,GenBankX64317.1). This PCR generates an amplicon of 210 and 270 bp with L. (L) mexicana (MHOM/MX/84/SETGS) and 230 bp with L. (V) braziliensis (MHOM/BR/75/M2903). Results: Out of 65 impression smears of clinical samples 50 were positive according to PCR (76.9%) and 29 were positive according to microscopic observation (44.6%). The primers did not hybridized with human, Trypanosoma cruzi, Staphylococcus aureus, Staphylococcus epidermidis or Pseudomona aeruginosa DNA. Of the positive smears, 84% (42/50) corresponded to L. (L) mexicana and 16% (8/50) to L. (V) braziliensis. Conclusion: A one-step PCR with primers LU-5A and LME improves the diagnostic capacity to differentiate between Leishmania and Viannia subgenera in parallel with conventional tests.