TABLE 3.

Dual-combination 24-h time-kill results for changes in the log₁₀ CFU per milliliter of Enterococcus faecalis from the initial inoculum^a

Drug at 0.0625× MIC	Mean change in log10 CFU/mL of strain ± SD
	Penicillin susceptible								Penicillin elevated
	JH2-2 (ampicillin MIC of 2 mcg/mL; penicillin MIC of 2 mcg/mL)				L2052 (ampicillin MIC of 0.5 mcg/mL; penicillin MIC of 2 mcg/mL)				L2068 (ampicillin MIC of 1 mcg/mL; penicillin MIC of 8 mcg/mL)				LS4828 (ampicillin MIC of 8 mcg/mL; penicillin MIC of 8 mcg/mL)
	Ceftriaxone		Ceftaroline		Ceftriaxone		Ceftaroline		Ceftriaxone		Ceftaroline		Ceftriaxone		Ceftaroline
	0.25× MIC	0.5× MIC	0.25× MIC	0.5× MIC	0.25× MIC	0.5× MIC	0.25× MIC	0.5× MIC	0.25× MIC	0.5× MIC	0.25× MIC	0.5× MIC	0.25× MIC	0.5× MIC	0.25× MIC	0.5× MIC
Penicillin	0.68 ± 0.39	−0.66 ± 0.79	−1.90 ± 0.10	−2.32 ± 0.06	0.31 ± 1.45	0.85 ± 0.87	1.59 ± 0.21	1.01 ± 0.35	0.40 ± 0.08	0.02 ± 0.08	−0.12 ± 0.13	−2.34 ± 0.09	0.54 ± 0.12	0.22 ± 0.32	0.63 ± 0.00	0.86 ± 0.02
Ampicillin	−3.44 ± 0.70	−3.81 ± 0.26	−3.18 ± 0.56	−3.64 ± 0.36	1.24 ± 0.56	1.10 ± 0.75	1.44 ± 0.07	0.30 ± 0.05	1.99 ± 0.12	1.65 ± 0.19	−0.27 ± 0.01	−2.57 ± 0.44	0.59 ± 0.00	0.56 ± 0.32	0.71 ± 0.06	0.41 ± 0.06
Piperacillin-tazobactam	0.08 ± 0.13	−1.69 ± 0.08	1.31 ± 0.03	0.14 ± 0.05	0.56 ± 0.25	0.30 ± 0.05	1.82 ± 0.14	1.41 ± 0.04	1.30 ± 0.15	2.23 ± 0.10	0.07 ± 0.07	−2.97 ± 0.30	0.42 ± 0.12	0.48 ± 0.11	0.76 ± 0.12	0.32 ± 0.49
Ertapenem	−1.96 ± 0.75	−2.88 ± 0.09	−0.32 ± 0.10	−2.39 ± 0.00	1.39 ± 0.02	1.42 ± 0.10	0.48 ± 0.18	1.40 ± 0.07	1.02 ± 0.06	−1.03 ± 0.45	−0.92 ± 0.11	−3.49 ± 0.49	0.48 ± 0.20	0.43 ± 0.04	0.35 ± 0.19	0.22 ± 0.00
Imipenem-cilastatin	0.10 ± 0.18	−1.44 ± 0.08	1.48 ± 0.06	0.44 ± 0.30	0.04 ± 0.32	1.18 ± 0.55	0.26 ± 0.25	1.44 ± 0.07	0.08 ± 0.15	−1.47 ± 0.48	−1.84 ± 0.04	−3.88 ± 0.00	0.54 ± 0.03	0.53 ± 0.10	0.42 ± 0.04	0.36 ± 0.16
Meropenem	−3.04 ± 0.00	−3.32 ± 0.71	−2.95 ± 0.04	−3.43 ± 0.13	1.05 ± 0.72	0.43 ± 0.95	1.42 ± 0.02	0.72 ± 1.13	−0.57 ± 0.02	−1.29 ± 1.04	−1.96 ± 0.04	−3.54 ± 0.43	0.41 ± 0.12	0.31 ± 0.20	0.37 ± 0.21	0.10 ± 0.01

^aAntibacterial activity was defined as bactericidal ≥3 log₁₀ CFU/mL or bacteriostatic <3 log₁₀ CFU/mL decrease from initial inoculum at 24 h.