TABLE 9.

Potency of meropenem alone or in combination with xeruborbactam or vaborbactam against selected KPC-producing strains and their plasmid-loss derivatives

KPC-producing strain	Beta-lactamases	Description ofa:		Meropenem MIC (μg/mL)			KPC-lacking derivative strain	Beta-lactamase(s)	Meropenem MIC (μg/mL)
		OmpK35	OmpK36	Alone	With xeruborbactam at 8 μg/mL	With vaborbactam at 64 μg/mL			Alone	With xeruborbactam at 8 μg/mL	With vaborbactam at 64 μg/mL
KP1004	KPC-2, TEM-1, SHV-11	FS from aa 42	Full copy	16	0.004	0.03	KPM1206	SHV-11	0.03	0.008	0.03
KP1074	KPC-3, SHV-11, TEM	FS from aa 42	GD	64	0.03	0.125	KPM1211	SHV-11	0.125	0.06	0.125
KP1084	KPC-3, SHV-11, TEM-1	FS from aa 42	GD	64	0.06	0.125	KPM1311	SHV-11	0.125	0.03	0.125
KP1087	KPC-2, CTX-M-15, SHV-11, TEM-1	FS from aa 208	GD	64	0.06	0.125	KPM1304	SHV-11 CTX-M-15	1	0.06	0.125
KP1093	KPC-3, SHV-11, TEM-1	FS from aa 42	GD	128	0.125	0.25	KPM2042	SHV-11	0.25	0.06	0.125
KP1094	KPC-2, TEM-1, LEN-17	Stop at aa 230	Stop at aa 92	>256	0.25	0.25	KPM1977	LEN-17	0.5	0.25	0.25
KP1100	KPC-3, TEM, SHV	FS from aa 42	GD	>256	0.125	0.5	KPM2136	SHV-11	0.5	0.03	0.25
KP1251	KPC-3, TEM, SHV	FS from aa 42	Full copy	64	0.004	0.03	KPM2626	SHV	0.03	0.004	0.03
KP1254	KPC-2, TEM, SHV, OXA-10	FS from aa 42	IS insertion and deletion	>256	2	4	KPM2841	SHV-11 OXA-10	4	1	2
KP1099	KPC-2, SHV-11, CTX-M-14, SHV-12	FS from aa 29	GD	128	0.125	0.25	KPM2898	SHV-11 CTX-M-14	2	0.06	0.25

^aaa, amino acid; FS, frameshift; GD, insertion of two amino acids, Gly134Asp135, in the L3 loop of OmpK36, resulting in a partially functional OmpK36 with a constricted channel.