Background: Analysis of the in vitro sensitivity of clinical isolates of different yeast species to amphotericine B and two inhibitors of cell wall beta-glucane synthesis: the lipopeptide cilofungin and the liposaccharide papulacandin B, as well as the possible interactions among these antifungal types.
Methods: The in vitro sensibility of C. albicans strains and other yeast species of clinical origin was studied, using the macrodilution method in RPMI broth as recommended by NCCLS. In six C. albicans and two T. glabrata strains the interaction between amphotericine B and one of the beta-glucan inhibitors was also assessed, by combining one antifungal agent in a two-fold dilution series with subinhibitory concentrations (1/4MIC) of the second antifungal.
Results and conclusions: Of all three antifungals, amphothericine B proved to be the more active one, with a MIC90 of 1.25 micrograms/ml for C. albicans. MIC90 of cilofungin and papulacandine B is 5 micrograms/ml for both antifungals. The spectrum of action for the different yeast species is broader for papulacandin B than for cilofungin. On the other hand, no synergism has been observed between the two glucane inhibitors and amphotericine B.