Development and validation of PCR-based assays for diagnosis of American cutaneous leishmaniasis and identification of the parasite species

Mem Inst Oswaldo Cruz. 2012 Aug;107(5):664-74. doi: 10.1590/s0074-02762012000500014.

Abstract

In this study, PCR assays targeting different Leishmania heat-shock protein 70 gene (hsp70) regions, producing fragments ranging in size from 230-390 bp were developed and evaluated to determine their potential as a tool for the specific molecular diagnosis of cutaneous leishmaniasis (CL). A total of 70 Leishmania strains were analysed, including seven reference strains (RS) and 63 previously typed strains. Analysis of the RS indicated a specific region of 234 bp in the hsp70 gene as a valid target that was highly sensitive for detection of Leishmania species DNA with capacity of distinguishing all analyzed species, after polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). This PCR assay was compared with other PCR targets used for the molecular diagnosis of leishmaniasis: hsp70 (1400-bp region), internal transcribed spacer (ITS)1 and glucose-6-phosphate dehydrogenase (G6pd). A good agreement among the methods was observed concerning the Leishmania species identification. Moreover, to evaluate the potential for molecular diagnosis, we compared the PCR targets hsp70-234 bp, ITS1, G6pd and mkDNA using a panel of 99 DNA samples from tissue fragments collected from patients with confirmed CL. Both PCR-hsp70-234 bp and PCR-ITS1 detected Leishmania DNA in more than 70% of the samples. However, using hsp70-234 bp PCR-RFLP, identification of all of the Leishmania species associated with CL in Brazil can be achieved employing a simpler and cheaper electrophoresis protocol.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't
  • Validation Study

MeSH terms

  • DNA, Protozoan / genetics*
  • HSP70 Heat-Shock Proteins / genetics*
  • Humans
  • Leishmania / genetics*
  • Leishmania / isolation & purification
  • Leishmaniasis, Cutaneous / diagnosis*
  • Leishmaniasis, Cutaneous / parasitology
  • Polymerase Chain Reaction / methods*
  • Polymorphism, Restriction Fragment Length
  • Sensitivity and Specificity

Substances

  • DNA, Protozoan
  • HSP70 Heat-Shock Proteins