Isolation, Typing and Susceptibility Evaluation of Local Isolates of Leishmania Parasite Causes Cutaneous Leishmaniasis Against Pentavalent Antimonials

Abstract

Cutaneous leishmaniasis (CL) is one of the most important endemic diseases in Syrian Arab Republic, (CL) is caused by a protozoan parasite of the genus Leishmania which is transmitted to human through the bite of sand fly female. The pentavalent antimony Sb(V) is the first-line treatment for more than 70 years. Recently, several cases of therapeutic failures and clinical relapses have been reported, and these cases indicate the emergence and spread of SbV-resistant strains, Therefore, it becomes necessary to characterize the local Leishmania strains depending on the species and the degree of response to antimonials. Based on previous facts, this study aimed to identify Leishmania strains isolated from CL patients and evaluate susceptibility of these clinical isolates towards each of glucantime and pentostam. This study was conducted with four cultures of Leishmania (L1 – L4) from patients with cutaneous ulcer, these isolates have been typed using the PCR-RFLP-ITS1 analysis, and the Half-maximal inhibitory concentration (IC50) was determined for each compound by conducting MTT viability assay for all isolates after treatment for 24 hours. The results of molecular typing showed that all isolates were L. tropica , and the values of IC50 revealed the different degrees of drug susceptibility towards each of glucantime and pentostam for all isolates, and each one of the four isolates had the same ranking towards each of the two drug compounds, The results also represented that the inhibitory rate of parasites treated with pentostam compared with glucantime was found to be significantly higher. In fact, based on our findings, There is a clear differences between local isolates of L. tropica species in

terms of susceptibility against all forms of pentavalent antimony compounds.