ASSESSMENT OF AMPHOTERICIN-B SUSCEPTIBILITY IN LEISHMANIA-INFANTUM PROMASTIGOTES BY FLOW CYTOMETRIC MEMBRANE-POTENTIAL ASSAY

Flow cytometry was used for measuring the effects of amphotericin B on the membrane of Leishmania infantum strains. The technique was adapte d from the rapid flow cytometric membrane potential assay developed by Ordonez and Wehman (Cytometry 22:154-157, 1995) for evaluating antibi otic-susceptibility of Candida species. The study consisted of measuri ng membrane potential changes induced by amphotericin B in 3 initial s trains and 12 laboratory-generated variants adapted to grow with ampho tericin B. Results showed that, after 3 h of incubation, amphotericin B induced a dose-related decrease of membrane potential that reached i ts maximal level at the same concentrations that inhibited parasite gr owth. These results suggest that the flow cytometric membrane potentia l assay could be used to assess the susceptibility of Leishmania proma stigotes to amphotericin B. (C) 1997 Wiley-Liss, Inc.