Killing kinetics of caspofungin, micafungin, and amphotericin B against Candida guilliermondii

Abstract

Amphotericin B (AMB), micafungin, and caspofungin MICs, minimal fungicidal concentrations, and time-killing curves were determined in the presence and absence of 10% inactivated serum. AMB was the only agent with consistent killing activity (time required to achieve 99.9% of growth reduction was 2.1 to 3.2 h). The presence of serum enhanced caspofungin activity but lowered those of micafungin and AMB.

FIG. 1.

Time-killing kinetics assays of AMB, micafungin, and caspofungin against C. guilliermondii. Average datum points and standard deviations are provided for eight C. guilliermondii isolates. Upper panels, RPMI medium. Lower panels, RPMI plus 10% inactivated FBS. A, amphotericin B; B, micafungin; C, caspofungin.

FIG. 2.

Relationship of amphotericin B, caspofungin, and micafungin concentrations and K values (regression lines) of survival time for C. guilliermondii in the presence (continuous line) or absence (dotted line) of inactivated fetal (10%) bovine serum. For caspofungin and micafungin, regression lines are practically horizontal (with and without serum) and almost identical (lines overlap).