TABLE 1.

MICs by Etest and broth microdilution and synergy testing by Etest and time-kill assay

E. faecium isolate (n = 24)	MIC (μg/ml) of:				Synergy testing
	DAP by:		RIF by:		Etestb		TKA log10 changea
	Etestb	BMD	Etestb	BMD	ΣFICs	Mean ΣFIC
1	4	2	0.008	0.032	0.3, 0.5, 0.8	0.6	−2.0 (SYN)
2	4	1	16	8	0.1, 0.1, 0.1	0.1	−2.0 (SYN)
3	2	2	0.032	0.064	0.9, 0.9, 0.9	0.9	−2.0 (SYN)
4	2	2	0.016	0.064	0.2, 0.2, 0.3	0.2	−4.0 (SYN)
5	2	2	0.016	≤0.016	0.3, 0.2, 0.2	0.2	−5.0 (SYN)
6	1	2	16	16	0.2, 0.3, 0.2	0.2	−2.4 (SYN)
7	2	2	16	8	0.3, 0.3, 0.3	0.3	−2.0 (SYN)
8	2	2	0.016	0.032	0.3, 0.3, 0.2	0.3	−2.1 (SYN)
9	2	2	>256	>32	0.4, 0.4, 0.3	0.4	−2.0 (SYN)
10	2	1	8	1	0.2, 0.3, 0.4	0.3	−2.0 (SYN)
11	2	2	32	8	0.2, 0.2, 0.3	0.2	−2.0 (SYN)
12	2	4	32	16	0.2, 0.4, 1.0	0.5	−2.6 (SYN)
13	4	4	32	8	0.1, 0.4, 0.2	0.2	−2.0 (SYN)
14	2	2	0.016	0.032	0.4, 0.3, 0.4	0.4	−2.5 (SYN)
15	1	1	16	4	0.4, 0.4, 0.3	0.4	−2.2 (SYN)
16	2	0.5	16	4	0.3, 0.2, 0.2	0.2	−2.0 (SYN)
17	4	2	32	16	0.2, 0.2, 0.2	0.2	−2.0 (SYN)
18	4	1	0.032	0.032	1.0, 1.0, 1.0	1.0	−2.0 (SYN)
19	2	1	32	4	0.2, 0.2, 0.1	0.2	−1.4 (IND)
20	4	2	0.016	≤0.016	0.4, 0.3, 0.5	0.4	−0.9 (IND)
21	2	2	16	4	0.1, 0.2, 0.2	0.2	−1.4 (IND)
22	2	1	8	4	0.4, 0.4, 0.3	0.4	−0.6 (IND)
23	2	1	32	8	0.3, 0.3, 0.3	0.3	−1.0 (IND)
24	4	2	8	4	0.2, 0.2, 0.3	0.2	−0.5 (IND)

^aValues represent the log₁₀ change (CFU/ml) in the TKA after 24-h exposure to DAP and RIF when compared to the most active drug alone. Negative values indicate a decrease in colony count. SYN, synergy; IND, indifference.

^bPerformed in triplicate.