Genetic analysis of clinical isolates of Leishmania major from Isfahan, Iran.

BACKGROUND & OBJECTIVES: Leishmaniasis is a geographically widespread severe disease which includes visceral leishmaniasis (VL) and cutaneous leishmaniasis (CL). There are 350 million people at risk in over 80 countries. In the Old World, CL is usually caused by Leishmania major, L. tropica, and L. aetiopica complex of which 90% of cases occur in Afghanistan, Algeria, Iran, Iraq, Saudi Arabia, Syria, Brazil and Peru. Recently, Eslami et al (2011) reported a novel TRYP6 gene encoding tryparedoxin peroxidase from an Iranian L. major strain exhibiting homology with the related gene in a divergent genus of Kinetoplastida, the Crithidia. This prompted us to analyze the mentioned gene in 100 isolates obtained from patients with suspected CL. Consequently, we analyzed internal transcribed spacer 1 (ITS1) region, RNA polymerase II largest subunit (RPOIILS) and the mitochondrial DNA polymerase beta (DPOLB).

METHODS: After obtaining samples from 100 patients, DNA extraction was performed and TRYP6 was analyzed using conventional PCR. All samples harbouring TRYP6 with smaller size (555 bp) were analysed based on three other regions: ITS1, RPOIILS and DPOLB genes.

RESULTS: Results showed that 10% of the isolates have the same character as observed in our previous study. The ITS1-RFLP-PCR of this 10% isolates showed their similarity to the one from Crithidia fasciculata. RNA polymerase II largest subunit (RPOIILS) showed genetic diversity but the mitochondrial DNA polymerase beta (DPOLB) did not show any genetic diversity.

CONCLUSION: This study might also help in solving the problems concerning Leishmaniasis outbreaks currently reported in Iran and some other endemic regions of the world.