Table 3.

MUT056399 in vivo activity in the murine systemic and thigh infection models^a

S. aureus strain	MIC (μg/ml)			Mean ED50 (mg/kg/day) in murine systemic infection model			Murine thigh infection model
							Mean static MUT056399 dose (mg/kg/day)	Mean bacterial burden reduction (log10)b
	MUT056399	Vancomycin	Linezolid	MUT056399	Vancomycin	Linezolid		MUT056399	Linezolid
MSSA ATCC 29213	0.06	1	4	21.6	1.6	NDc	40	1.5	1.4
MRSA ATCC 33591	0.06	2	2	31.8	6.7	ND	45.5	1	0.7
MRSA NRS 382 (USA100)	0.06	2	2	19.3	6	ND	44	1	1.1
MRSA NRS 384 (USA300)	0.06	1	1	45.1	9.4	ND
MRSA NRS 385 (USA500)	0.06	1	1	28.3	5	ND
MRSA/GISA JUS	0.03	4	4	49.6	ND	3.6

^aIn the systemic infection model, the ED₅₀ was the dose that allowed the survival of 50% of each group of treated mice at 48 h postinfection in at least two experiments. In the thigh infection model, bacterial recovery in the thighs of infected animals was performed at 20 h postinfection. All calculations were performed using XL-Stat software. P values were determined with the Dunnett test. Mean values of at least two experiments are shown.

^bThe mean bacterial burden reduction in the thigh was measured after a single administration of MUT056399 or linezolid at 50 mg/kg.

^cND, not done.