Treatment of disseminated Torulopsis glabrata infection with DO870 and amphotericin B

Abstract

One day prior to challenge, the organisms were subcultured to 50 ml of brain heart infusion (BHI) broth (BBL, Cockeysville, Md.). The fungi were incubated on a shaker at 37°C overnight, washed twice with 0.9% NaCl, quantified with a hemacytometer, and adjusted to the desired concentration in normal saline. The counts were verified by determining CFU counts with 10-fold serial dilutions in 0.9% NaCl. Each mouse was infected with 1.1 x 108 to 7 x 108 CFU/ml in the lateral tail vein given in a 0.2-ml volume. The T. glabrata cells were agitated between each injection to achieve a uniform suspension.Activity in vitro. The in vitro susceptibility studies were performed by the broth macrodilution technique proposed by the National Committee for Clinical Laboratory Standards (7). The medium was RPMI 1640 with glutamine, buffered by MOPS (morpholinepropanesulfonic acid) at pH 7.0 (American Bioganics, Niagara Falls, N.Y.). The inoculum was prepared from 24-h Sabouraud dextrose agar (Difco Laboratories, Detroit, Mich.) subcultures of T. glabrata incubated at 35°C. Colonies of T. glabrata were suspended in 5 ml of sterile distilled water, and the cell density was adjusted with a spectrophotometer to a 0.5 McFarland standard at a 530-nm wavelength. The working suspension was a 1:100 dilution of the organisms followed by a 1:20 dilution of the suspension with RPMI broth medium. A volume of 0.9 ml of the adjusted solution was dispensed into tubes containing 0.1 ml of 10 times the concentrations of the drugs to be tested. The test tubes were incubated at 35°C for 48 h.

Combination Antifungal Therapy

“…Polyene-azole combinations have been carefully studied in several animal models of invasive candidiasis, including models using mice (9,113,157,158,176,199,202,203,206 (115,176,208). Some of the findings with these animal models are contrary to those of in vitro reports of antagonism, and although positive effects have been observed, it is difficult for an azole-polyene combination to improve on the activity of amphotericin B alone.…”

“…Concurrent fluconazole-amphotericin B combinations have been promising in these animal models, since there are several reports of improved survival or tissue clearance with this combination. Importantly, most of these animal models have used C. albicans; the potential of combination therapy could be even greater with less-susceptible species (9). Amphotericin and fluconazole have been employed concurrently for management of candidemia in a large clinical trial (166) and produced favorable results.…”

Use of amphotericin B with azole antifungal drugs: what are we doing?

“…DO870 has been evaluated with and without amphotericin B in a murine (4). The literature on amphotericin B-fluconazole interactions in candidiasis is thin, and given the recent demonstration of the utility of fluconazole in treating patients with candidemia (23), this interaction is certainly the most intriguing for the practitioner.…”

Combination therapy of murine invasive candidiasis with fluconazole and amphotericin B

“…On the basis of these studies, some investigators have cautioned against using these drugs in combination in patients with candidiasis (15,16). Animal models of fungal infections have been used to measure the efficacies of various combinations of antifungal agents, including azoles and polyenes (1,2,4,6,8,17,18,20,21). However, the data are conflicting and difficult to interpret since they are derived from markedly different infection models and dosing regimens.…”