Table 1.

Characteristics of the strains used

		MIC (mg/L)a
Strain	β-Lactamase	Aztreonam	Nacubactam	Aztreonam/nacubactamb
K. pneumoniae
ȃATCC BAA-2473	NDM-1	256	256	1
ȃMSC 21664	IMP-6, CTX-M-2	32	16	0.016
ȃMSC 21444	OXA-48	512	2	1

MIC value is the median of technical replicates (n = 3).

MIC of nacubactam measured with a fixed aztreonam concentration of 4 mg/L.