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)aED50 (mg/kg)b95% CIc
S. aureus 3816
    8 × 108CAZd1622.619.4-26.4
    8 × 106AM-11212.62.2-3.1
    8 × 106CAZ-AM-112 (4:1)NDe4.8 + 1.24.0-5.8
    8 × 106CAZ-AM-112 (7:1)ND7 + 16.6-9.7
E. cloacae P99
    2.2 × 107CAZ128>100ND
    2.2 × 107AM-112321911.6-33.4
    2.2 × 107CAZ-AM-112 (1:1)2 + 22 + 21.0-5.5
    2.2 × 107CAZ-AM-112 (2:1)4 + 23.8 + 1.92.3-5.9
    2.2 × 107CAZ-AM-112 (4:1)4 + 111.6 + 2.97.2-17.4
K. pneumoniae SHV-5
    6 × 108CAZ128>160ND
    6 × 108AM-11216>40ND
    6 × 108CAZ-AM-112 (1:1)16 + 1633.6 + 33.625.1-45.1
    6 × 108CAZ-AM-112 (2:1)32 + 1623.8 + 11.918.8-30.1
  • a MICs quoted for CAZ-AM-112 combinations are expressed as CAZ + AM-112 MIC.

  • b ED50 values for CAZ-AM-112 combinations are expressed as CAZ + AM-112 ED50 values.

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

  • d CAZ, ceftazidime.

  • e ND, not determined.