Investigation of Drug Resistance in Leishmania tropica as Causative Agent of Canine Leishmaniasis

Objective: Leishmaniasis is endemic in 98 countries, and poses risk to 1 billion people in the world. The infection caused by obligatory intracellular parasite Leishmania spp. in dogs is called Canine Leishmaniasis (CanL). In this study, it was aimed to detect the resistance status of Leishmania tropica strains isolated from dogs in our country against amphotericin B, meglumine antimoniate and sodium stibogluconate applied in leishmaniasis treatment. Method: Leishmania spp. promastigotes, taken out from the liquid nitrogen were first cultured in NNN media, then the growing isolates were transferred to RPMI-1640 medium and abundant amount of promastigotes were obtained. Isolates were genotyped using real-time polymerase chain reaction method with primers and probes specific to the ITS-1 region of Leishmania spp. and in five isolates that were found to be L. tropica causing CanL, resistance status against amphotericin B, meglumine antimoniate and sodium stibogluconate was investigated by hemocytometer and XTT methods. Results: The mean IC50 values were determined as 10.60 mg/ml for meglumine antimoniate, 0.1471 mg/ml for sodium stibogluconate, 0.0328 μM/ml for amphotericin B by hemocytometer method. Average IC50 values determined by XTT method were 10.48 mg/ml for meglumine antimoniate, 0.1470 mg/ml for sodium stibogluconate, 0.0326 μM/ml for amphotericin B. Conclusion: According to our data, while L. tropica strains which were isolated from CanL cases which are very rarely found causative agents in dogs, were not found to be resistant to amphoreticin B and sodium stibogluconate, parasite developed drug resistance against meglumine antimoniate. In future, this situation is thought to be a problem during treatment in human cutaneous leishmaniasis cases.