Evaluation of a Possible Synergistic Effect of Meglumine Antimoniate with Paromomycin, Miltefosine or Allopurinol on in Vitro Susceptibility of Leishmania tropica Resistant Isolate

BACKGROUND: Pentavalent antimonials are still the first choice treatment for leishmaniasis, but with low efficacy and resistance is emerging. In the present study, the effect of meglumine antimoniate (MA, Glucantime) combined with paromomycin, miltefosine or allopurinol on in vitro susceptibility of Leishmania tropica resistant isolate was evaluated. METHOD: The drugs were obtained from commercial sources and diluents of each drug in medium were prepared on the day of experiment. J774 A.1 murine macrophage cell lines were attached to the cultured on slide and incubated at 37 °C with 5% CO(2) for 24 h. Then the stationary phase promastigotes were added to the cells and after 4 hrs of incubation different concentrations of MA, paromomycin, miltefosine or allopurinol were added and incubated for an additional of 72 h. Then the slides were dried and fixed with methanol, stained by Giemsa and studied under a light microscope. Drug activity was evaluated by assessing the macrophage infection rate and the number of amastigotes per infected macrophage was done by examining 100 macrophages. The experiment was done in triplicates. RESULT: Various concentrations of MA along with paromomycin, miltefosine or allopurinol significantly inhibited (P<0.01) the proliferation of L. tropica amastigote stage in the macrophage cell line as compared with MA alone or positive control. CONCLUSION: Combination of Glucantime with paromomycin, miltefosine or allopurinol showed a synergistic effect on the clinical isolate of L. tropica in vitro. Use of combination therapy is a new hope and a logical basis for therapy of the patients with cutaneous leishmaniasis. Further investigations are needed to evaluate the therapeutic effects of these drugs on the CL patients.