TABLE 4

In vitro whole-cell susceptibility and 1,3-β-glucan synthase inhibition profiles of caspofungin and MK-3118 for representative strains included in the studya

StrainOrganismFksp phenotypeMIC (mg/liter)bIC50 (ng/ml)
CASMK-3118
Fks1pFks2pNo serum50% serumNo serum50% serumCSFMK-3118
DPL225C. albicansWT<0.030.120.030.51.42132.95
DPL1010C. albicansS645F2>160.1212,321423.1
DPL1012C. albicansD648Y0.2516<0.032149.851.58
DPL18C. albicansF641S0.5>16116>2,500c>2,500c
DPL1021C. glabrataWTWT0.0610.254125.9108.1
DPL235C. glabrataWTF659V>16>160.581,945542.1
DPL32C. glabrataWTD666G2>160.542,27336.25
DPL1034A. fumigatusWT0.12ND0.12ND0.657.81
DPL1035A. fumigatusS678Pd>16ND0.12ND100.43.58
  • a MIC values represent whole-cell susceptibility; IC50 values represent 1,3-β-glucan synthase inhibition. CSF, cerebrospinal fluid; ND, not determined.

  • b MEC in the case of A. fumigatus.

  • c No significant inhibition at all levels.

  • d This mutation is equivalent to S645P in C. albicans (9).