Table 2.

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

Regimen	Trough (mg/liter)a		Outcome
	CPT	NXL104
K. pneumoniae 27-908M bearing KPC-2b
NXL104 AUC = 192, q24h	3.2	0.12	Fail
NXL104 AUC = 96, q12h	3.2	1.4-1.5	Fail
NXL104 AUC = 64, q8h	3.2	2.5-2.9	Succeed
K. pneumoniae 24-1318A bearing CTX-M-15c
NXL104 AUC = 32, q8h	3.2	1.1-1.2	Succeed
NXL104 AUC = 108, q12h	2.2	1.3-1.4	Succeedd
E. cloacae 2-77C bearing stably derepressed AmpCe
NXL104 AUC = 192, q24h	3.2	0.16	Fail
NXL104 AUC = 96, q12h	3.2	1.5-1.6	Fail
NXL104 AUC = 64, q8h	3.2	2.9-3.4	Succeed

^aThe 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.

^bThe 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.

^cThe 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.

^dThis regimen was CPT at 900 mg, q12h, and NXL104 at 900 mg, q12h.

^eThe 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.