. 2020 May 21;64(6):e00552-20. doi: 10.1128/AAC.00552-20

TABLE 1.

PV_max of QPX7728 for enhancement of the activity of meropenem against isogenic strains of KPC-3-producing K. pneumoniae with various combinations of efflux and porin mutations^a

KPC-3-producing strain	Recipient strain	Genotype/construction	Expression			Meropenem MIC (μg/ml) for KPC-3-producing strain with:			Meropenem MIC (μg/ml) for recipient	PV_max (μg/ml)
KPC-3-producing strain	Recipient strain	Genotype/construction	OmpK35	OmpK36	AcrAB	No drug	QPX	VAB	Meropenem MIC (μg/ml) for recipient	QPX	VAB
KPM1271	KPM1026a	Wild type	FL	FL	BL	16	0.016	0.06	0.06	0.125	0.25
KPM2601	KPM2600	ΔompK35	NF	FL	BL	32	0.016	0.06	0.06	0.125	1
KPM2599	KPM2592	ΔompK36	FL	NF	BL	32	0.03	0.25	0.06	1	16
KPM2067	KPM2040	ompK36_fs	FL	NF	BL	64	0.03	0.5	0.125	2	16
KPM2631	KPM2613	ompK36_fs ΔompK35	NF	NF	BL	256	0.25	4	0.25	2	64
KPM2965	KPM2966	ramR ompK36_fs ΔompK*35	NF	NF	Up	256	0.5	8	0.5	4	64
KPM1272	KPM1027	ramR_fs	Down	FL	Up	16	0.016	0.06	0.06	0.25	2
KPM2818	KPM2658	ramR_fs ΔompK36	Down	NF	Up	256	0.5	8	0.5	4	64
	KPM1007	ΔacrB	FL	FL	NF	ND	ND	ND	0.06	ND	ND
KP1004	KPM1206	ompK35_fs	NF	FL	BL	32	0.016	0.03	0.03	0.25	2
KP1074	KPM1211	ompK35_fs ompK36_GD	NF	GD	BL	128	0.06	1	0.125	2	32

All strains produced KPC-3 and TEM-1, the genes for which were carried by plasmid pKpQIL. Both the KPM1026a derivatives and clinical isolates also produced a chromosomal SHV enzyme, encoded by bla_SHV-24 and bla_SHV-11, respectively. ompK35_fs and ompK36_fs, truncated porins due to the frameshift mutation; ramR*, truncated ramR due to the stop codon; FL, full length; NF, nonfunctional; BL, basal level; Up, overexpressed; Down, downregulated; QPX, QPX7728; VAB, vaborbactam at 4 μg/ml; ND, not determined; GD, duplication of two amino acids, Gly134 and Asp135, located within the L3 internal loop and associated with the reduced susceptibility to carbapenems due to constriction of the channel; PV_max, maximal potentiating value, which is the concentration of the BLI that reduces the meropenem MIC to the level seen in the parent strain that lacks KPC, which corresponds to the complete inhibition of KPC. KPC-3-producing strain was not constructed for KPM1007.