TABLE 4.

ED₅₀ values for combinations of ceftazidime and AM-112 against various pathogens in a murine intraperitoneal sepsis model

Organism or inoculum (CFU/ml)	Compound (ratio)	MIC (μg/ml)a	ED50 (mg/kg)b	95% CIc
S. aureus 3816
8 × 108	CAZd	16	22.6	19.4-26.4
8 × 106	AM-112	1	2.6	2.2-3.1
8 × 106	CAZ-AM-112 (4:1)	NDe	4.8 + 1.2	4.0-5.8
8 × 106	CAZ-AM-112 (7:1)	ND	7 + 1	6.6-9.7
E. cloacae P99
2.2 × 107	CAZ	128	>100	ND
2.2 × 107	AM-112	32	19	11.6-33.4
2.2 × 107	CAZ-AM-112 (1:1)	2 + 2	2 + 2	1.0-5.5
2.2 × 107	CAZ-AM-112 (2:1)	4 + 2	3.8 + 1.9	2.3-5.9
2.2 × 107	CAZ-AM-112 (4:1)	4 + 1	11.6 + 2.9	7.2-17.4
K. pneumoniae SHV-5
6 × 108	CAZ	128	>160	ND
6 × 108	AM-112	16	>40	ND
6 × 108	CAZ-AM-112 (1:1)	16 + 16	33.6 + 33.6	25.1-45.1
6 × 108	CAZ-AM-112 (2:1)	32 + 16	23.8 + 11.9	18.8-30.1

^aMICs quoted for CAZ-AM-112 combinations are expressed as CAZ + AM-112 MIC.

^bED₅₀ values for CAZ-AM-112 combinations are expressed as CAZ + AM-112 ED₅₀ values.

^c95% CI, confidence intervals for ceftazidime or AM-112; for combinations, 95% CI refers to ceftazidime component.

^dCAZ, ceftazidime.

^eND, not determined.