TABLE 1.

MICs of β-lactams and non-β-lactams for K. pneumoniae strains producing wild-type and modified KPC-2 and KPC-3^b

Isolate or mutant	MIC (μg/ml) of:											KPC mutation characteristic
	PIP	PIP-TAZ	CAZ	CAZ-AVI	ETP	IPM	IPM-REL	MEM	MEM-VAB	ATM	ATM-AVI	Mutation	Source, reference, or allelea	Position in protein
P-KPC−2	≥256	≥256	32	0.5	8	8	0.5	8	0.5	128	0.5	NA	NA	NA
M1a	≥256	128	64	16	0.5	2	0.25	1	0.064	64	0.5	T243M	This study	β7-β8
M2a	≥256	128	128	8	1	4	0.5	2	0.064	128	0.5	R164H	This study	Ω-loop
M3a	≥256	16	64	8	1	4	0.25	1	0.064	64	0.5	S109P	This study	α3-α4
M4a	≥256	8	64	8	0.25	0.5	0.125	0.5	0.064	8	0.125	D179A	23	Ω-loop
M5a	≥256	8	64	8	0.5	2	0.25	1	0.064	8	0.125	T243P	This study	β7-β8
M6a	≥256	32	64	8	0.5	2	0.125	0.5	0.064	16	0.25	A35G	This study	α1
M7a	128	4	≥256	32	0.125	0.25	0.125	0.125	0.064	2	0.125	D179V	KPC-57	Ω-loop
M8a	≥256	16	≥256	64	0.25	0.25	0.125	0.5	0.064	4	0.125	D179Y	KPC-33	Ω-loop
M9a	≥256	128	64	16	1	2	0.25	0.5	0.064	32	0.25	R178P	This study	Ω-loop
M10a	≥256	128	≥256	16	1	4	0.5	0.5	0.064	128	0.5	D176N	This study	Ω-loop
M11a	128	16	64	16	0.25	1	0.125	0.25	0.032	8	0.125	D176Y	21	Ω-loop
M12a	≥256	4	64	16	0.125	0.25	0.125	0.064	0.064	2	0.125	R164P	23	Ω-loop
M13a	≥256	32	128	32	0.125	0.5	0.25	0.064	0.064	2	0.125	Del174–Del177	This study	Ω-loop
M14a	≥256	4	64	32	0.064	0.25	0.125	0.064	0.064	2	0.125	Del171–Del174	This study	Ω-loop
M15a	≥256	16	64	16	0.064	4	0.5	0.064	0.064	2	0.125	AT ins at 243	This study	β7-β8
M16a	≥256	16	128	64	0.125	2	0.25	0.125	0.064	8	0.125	20-aa ins at 288	This study	α12
P-KPC-3	≥256	≥256	32	2	8	4	0.25	4	0.5	128	0.5	NA	NA	NA
M1b	≥256	256	≥256	64	0.25	2	0.125	0.5	0.064	128	0.5	8-aa ins at 271	This study	β9-α12
M2b	≥256	64	≥256	64	0.125	0.5	0.125	0.5	0.064	128	0.5	S171P	KPC-61	Ω-loop
M3b	≥256	16	128	16	0.125	0.25	0.125	0.125	0.032	32	0.125	D179G	This study	Ω-loop
M4b	≥256	8	64	16	0.125	0.25	0.125	0.125	0.032	64	0.5	P67Q	This study	β3
M5b	≥256	256	64	16	0.25	1	0.125	0.125	0.032	32	0.125	P174L	22	Ω-loop
M6b	≥256	16	64	32	0.125	0.5	0.125	0.064	0.032	4	0.125	D176Y	22	Ω-loop
M7b	≥256	16	256	64	0.125	0.25	0.125	0.064	0.032	32	0.5	D179Y	KPC-31	Ω-loop
M8b	≥256	32	128	32	0.125	2	0.25	0.064	0.032	64	0.5	T243P	22	β7-β8
M9b	≥256	16	64	16	0.125	2	0.125	0.064	0.032	64	0.25	T243M	22	β7-β8
M10b	≥256	32	128	64	0.125	2	0.125	0.064	0.032	64	0.5	A172P	22	Ω-loop

^aReference given if in vitro mutant was identified in a previous study.

^bResistant strains based on EUCAST breakpoints are highlighted with shading. CAZ, ceftazidime; AVI, avibactam; PIP, piperacillin; TAZ, tazobactam; ETP, ertapenem; IPM, imipenem; REL, relebactam; MEM, meropenem; VAB, vaborbactam; ATM, aztreonam; aa, amino acid; ins, insertion.