Table 2

Concentrations of ceftaroline and NXL104 at trough values associated with microbiological success and resistance suppression or treatment failure for several bacterial strains

RegimenTrough (mg/liter)aOutcome
CPTNXL104
K. pneumoniae 27-908M bearing KPC-2b
    NXL104 AUC = 192, q24h3.20.12Fail
    NXL104 AUC = 96, q12h3.21.4-1.5Fail
    NXL104 AUC = 64, q8h3.22.5-2.9Succeed
K. pneumoniae 24-1318A bearing CTX-M-15c
    NXL104 AUC = 32, q8h3.21.1-1.2Succeed
    NXL104 AUC = 108, q12h2.21.3-1.4Succeedd
E. cloacae 2-77C bearing stably derepressed AmpCe
    NXL104 AUC = 192, q24h3.20.16Fail
    NXL104 AUC = 96, q12h3.21.5-1.6Fail
    NXL104 AUC = 64, q8h3.22.9-3.4Succeed
  • a The ceftaroline (CPT) trough values indicated are nominal values. The actual values (measured at h 7) were always higher. The NXL104 concentrations were the result of modeling all the data for each regimen and simulating the 8-h NXL104 concentrations for the first 24 h.

  • b The MICs using serial dilutions of CPT and NXL104 fixed at 4 mg/liter were 0.75/4.0 mg/liter; the MICs using serial dilutions of both agents were 0.75/4.0 mg/liter.

  • c The MICs using serial dilutions of CPT and NXL104 fixed at 4 mg/liter were 0.12/4.0 mg/liter; the MICs using serial dilutions of both agents were 1.0/0.5 mg/liter.

  • d This regimen was CPT at 900 mg, q12h, and NXL104 at 900 mg, q12h.

  • e The MICs using serial dilutions of CPT and NXL104 fixed at 4 mg/liter were 0.75/4.0 mg/liter; the MICs using serial dilutions of both agents were 2.0/1.0 mg/liter.