Amphotericin B resistance of Aspergillus terreus in a murine model of disseminated aspergillosis

The in-vivo activity of amphotericin B and itraconazole against a clinical isolate of Aspergillus terreus was determined in a murine model of dissemin ated aspergillosis, MICs of amphotericin B and itraconazole for the strain, determined by an NCCLS-based technique, were 2 mu g/ml and 1 mu g/ml, resp ectively. Mice infected intravenously were treated with either itraconazole (50 or 100 mg/kg/day) or amphotericin B 4.5 mg/kg/day for 10 days. Treatme nt with both doses of itraconazole significantly prolonged the survival rat es compared with those for untreated mice. In comparison, mortality rate an d median survival time mere identical for mice treated with amphotericin B and for mice given no therapy, indicating that the strain was highly resist ant to amphotericin B in this model. Analysis of sterol composition showed that the major sterol was ergosterol, This suggests that amphotericin B res istance was not related to a modified sterol profile.