TABLE 3

Checkerboard assays of fluconazole-resistant C. albicans clinical isolates overexpressing the multidrug efflux pumps CDR1, CDR2, and MDR1 and/or overexpressing the drug target ERG11 as indicateda

Strain and compoundCompound concn (μg/ml)FLC concn (μg/ml)FICIOutcome
MIC1*MIC2*FICMIC1MIC2FIC
95-142 (CDR1/CDR2)
    1690.130.00264160.250.25Synergy
    2700.550.00864160.250.26Synergy
    3730.140.00264160.250.25Synergy
    4760.290.00464160.250.25Synergy
96-25 (MDR1/ERG11)
    1690.130.0023220.060.06Synergy
    2700.140.0023280.250.25Synergy
    3360.140.0043220.060.06Synergy
    4380.150.0043220.060.06Synergy
    580801323212Indifferent
12-99 (all four genes)
    1690.130.002128320.250.25Synergy
    2700.140.002128320.250.25Synergy
  • a MIC values were determined by a broth microdilution assay according to CLSI protocol M27-A3 (2008) using 50% growth reduction as the cutoff for the reported MIC values. MIC1, the MIC of the compound or FLC alone; MIC2, the MIC of the compound or FLC in the presence of FLC or compound, respectively. FIC, fractional inhibitory concentration; FICI, fractional inhibitory concentration index. *, values were converted from μM to μg/ml.