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 indicated^a

Strain and compound	Compound concn (μg/ml)			FLC concn (μg/ml)			FICI	Outcome
	MIC1*	MIC2*	FIC	MIC1	MIC2	FIC
95-142 (CDR1/CDR2)
1	69	0.13	0.002	64	16	0.25	0.25	Synergy
2	70	0.55	0.008	64	16	0.25	0.26	Synergy
3	73	0.14	0.002	64	16	0.25	0.25	Synergy
4	76	0.29	0.004	64	16	0.25	0.25	Synergy
96-25 (MDR1/ERG11)
1	69	0.13	0.002	32	2	0.06	0.06	Synergy
2	70	0.14	0.002	32	8	0.25	0.25	Synergy
3	36	0.14	0.004	32	2	0.06	0.06	Synergy
4	38	0.15	0.004	32	2	0.06	0.06	Synergy
5	80	80	1	32	32	1	2	Indifferent
12-99 (all four genes)
1	69	0.13	0.002	128	32	0.25	0.25	Synergy
2	70	0.14	0.002	128	32	0.25	0.25	Synergy

^aMIC 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.