TABLE 2.

Protective effects of S-4661 and other agents in murine systemic infections

Strain	Challenge dose (CFU/mouse)	Drug(s)	ED50 (mg/kg)	95% Confidence limit	MIC (μg/ml)
S. aureus Smith	1.1 × 106	S-4661	0.066	0.038–0.17	0.032
		Imipenem-cilastatin	0.050	0.031–0.14	0.016
		Meropenem-cilastatin	0.41	0.24–0.94	0.063
		Ceftazidime	14.7	7.30–47.9	8
Methicillin-resistant S. aureus TUH1	5.5 × 107	S-4661	19.2	11.9–31.3	4
		Imipenem-cilastatin	34.5	18.2–88.0	16
		Meropenem-cilastatin	48.4	28.0–132	16
		Vancomycin	3.10	2.01–4.45	1
E. coli C-11	9.0 × 105	S-4661	1.42	0.65–4.48	0.032
		Imipenem-cilastatin	2.41	1.29–7.04	0.063
		Meropenem-cilastatin	0.62	0.32–20.3	0.016
		Ceftazidime	1.69	0.86–7.15	2
P. aeruginosa
E7	2.5 × 104	S-4661	10.0	0.71–37.7	0.5
		Imipenem-cilastatin	7.13	1.31–15.5	2
		Meropenem-cilastatin	7.11	3.32–12.1	0.5
IPM2	5.3 × 105	S-4661	6.24	3.41–11.2	8
		Imipenem-cilastatin	2.42	1.45–4.32	16
		Meropenem-cilastatin	38.9	25.2–58.3	32
		Ceftazidime	>100	NCb	32
TUH302	3.0 × 104	S-4661	31.2	15.9–114.4	2
		Imipenem-cilastatin	32.4	17.9–91.1	8
		Meropenem-cilastatin	>100	NC	4
		Ceftazidime	>100	NC	64
S. pneumoniae TUH39a	1.9 × 106	S-4661	0.23	0.16–0.3	0.008
		Imipenem-cilastatin	0.24	0.17–0.32	0.008
		Meropenem-cilastatin	0.45	0.22–0.88	0.008
		Cefotaxime	4.85	3.71–7.13	0.125

^aPulmonary infection. 

^bNC, not calculated.