Influence of free or liposomal amphotericin B on killing of Candida species by human peritoneal macrophages.

The influence of free and liposomal amphotericin B at subinhibitory and inhibitory concentrations on killing of Candida albicans (ATCC 10231), Candida tropicalis (ATCC 13803) and Cryptococcus neoformans (930) by human peritoneal macrophages was investigated in vitro. Peritoneal macrophages were harvested from overnight peritoneal dialysate of 10 patients undergoing regular continuous ambulatory peritoneal dialysis and incubated with Candida species (1:2), pooled human serum, fetal calf serum, Medium 199 and Sabouraud broth (with or without amphotericin B) for 6 hours. The killing of Candida species was determined using subculture technique. The combination of amphotericin B (free or liposomal) with peritoneal macrophages enhanced the killing of the Candida species. Candidacidal activity of free and liposomal amphotericin B resulted in comparable effects; however, the killing of the yeasts by liposomal amphotericin B was slower than by free amphotericin B.