Rapid diagnosis of leishmaniasis by fluorogenic polymerase chain reaction

A fluorescent DNA probe (LEIS.P1) specific for a conserved region of the sm all-subunit ribosomal RNA gene of Leishmania and a pair of flanking primers (LEIS.U1 and LEIS.L1) were designed for use in a fluorogenic polymerase ch ain reaction. Optimal assay conditions with zero background were establishe d to detect low levels of Leishmania from clinical samples. By use of this assay, we amplified DNA from 27 strains of cultured Leishmania (both Old an d New World strains) and selectively amplified Leishmania DNA from 12 paraf fin-embedded human biopsy samples and 3 fresh human skin biopsy specimens. For the fresh human tissue biopsies, the turnaround time from biopsy to tes t result was < 24 hr. No amplification was detected in negative control sam ples (including the kinetoplastid protozoa Trypanosoma rangelli and Crithid ia fasiculata). This assay provides a specific and rapid diagnostic modalit y to detect infection with Leishmania.