LEISHMANIA-INFANTUM - LACK OF PARASITE RESISTANCE TO AMPHOTERICIN-B IN A CLINICALLY RESISTANT VISCERAL LEISHMANIASIS

Amphotericin B (AmB) has been used as a second-line treatment of visce ral leishmaniasis, particularly in human immunodeficiency virus-positi ve patients. AmB median effective doses (ED(50)s) were determined on a n isolate obtained before any treatment and on a second isolate obtain ed 4 years later from the same AmB-treated patient. ED(50)s were simil ar (0.059 and 0.067 mg/kg of body weight, respectively), demonstrating the first evidence of AmB ED50 stability of Leishmania infantum after a long-term drug exposure. An isoenzymatic study was performed in ord er to verify that the second isolate originated from the same parasite as the first isolate. The present case report showed that treatment f ailure,vas not due to parasite resistance in spite of a prolonged expo sure to the drug.