TABLE 8.

Potency of xeruborbactam and vaborbactam to enhance the activity of meropenem against the isogenic strains of KPC-3-producing K. pneumoniae with various combinations of efflux and porin mutations

KPC-3-containing strain	No-plasmid strain	Constructiona	Description ofb:			Meropenem MIC (μg/mL) with KPC-3 alone or with indicated BLI					MIC (μg/mL)
			OmpK35	OmpK36	AcrAB	Alone	With xeruborbactam at:		With vaborbactam at:
							1 μg/mL	8 μg/mL	8 μg/mL	64 μg/mL	No-plasmid strain	Xeruborbactamc	Vaborbactam
KPM1271	KPM1026a	Wild type	FL	FL	BL	16	0.03	0.004	0.03	0.03	0.03	16	>128
KPM1272	KPM1027	ramR_fs	Down	FL	Up	16	0.03	0.004	0.06	0.06	0.06	16	>128
KPM2601	KPM2600	ΔompK35	NF	FL	BL	32	0.03	0.008	0.06	0.06	0.06	16	>128
KPM2067	KPM2040	ompK36_fs	FL	NF	BL	64	0.125	0.008	0.125	0.125	0.125	16	>128
KPM2631	KPM2613	ompK36_fs ΔompK35	NF	NF	NL	256	1	0.125	1	0.25	0.25	32	>128
KPM1273	KPM1171	ramR_fs ompK36_1171	Down	NF	Up	>256	8	1	16	2	2	64	>128

^aramR_fs and ompK36_fs encode truncated proteins due to frameshift mutations.

^bFL, full length; NF, nonfunctional; BL, basal level; Up, overexpressed; Down, downregulated.

^cXeruborbactam MICs against strains producing and lacking KPC-3 were the same.