Fungicidal effect of amphotericin B in urine: in vitro study to assess feasibility of bladder washout for localization of site of candiduria

Abstract

An in vitro study was performed to determine the optimum amphotericin B concentration and exposure time required to kill various strains of Candida albicans in urine. This is a preliminary study to assess the feasibility of using amphotericin B bladder washout for localization of the site of candiduria. In broth kinetic killing studies, amphotericin B at a concentration of greater than 100 micrograms/ml produced almost complete killing of 5 x 10(5) CFU of C. albicans per ml within 1.5 to 2 h. In urine studies (with various pH values, osmolalities, and electrolyte concentrations), amphotericin B at a concentration of 200 micrograms/ml with a 2-h exposure time decreased fungal counts of 21 strains of C. albicans from 5 x 10(6) to less than 200 CFU/ml. Bladder washout with greater than or equal to 200 micrograms of amphotericin B per ml and a dwell time of 2 h can therefore sufficiently sterilize the bladder of yeasts and may be a useful localization test.