TABLE 1.

Susceptibility of 30 KPC-producing E. coli isolates to β-lactams

Isolate	Ribotype	MIC (μg/ml)a
		Broth microdilution method				Etest method
		IPM	MER	DOR	ETP	IPM	MER	DOR	ETP	CAZ	TZB
Brooklyn isolates
DM133	A	4	1	1	1	6	0.75	1	1.5	8	>256
KB86	A	4	0.5	1	1	4	0.5	1.5	0.75	24	>256
KB801	A	4	4	2	8	4	2	2	8	12	192
ME57	B	4	1	1	4	6	1	3	1.5	8	96
ME236	A	4	0.5	1	2	3	0.5	2	0.5	24	256
LU60	C	2	4	2	16	8	2	2	6	48	>256
MA82	A	8	16	4	32	12	6	12	24	>256	>256
MA46	D	8	2	2	4	12	3	3	6	256	>256
ME366	C	2	2	0.5	4	1	0.75	2	1.5	32	24
Queens isolates
E1	A	4	1	1	2	4	0.75	4	1	12	>256
E2	E	8	16	8	32	12	12	>32	>32	>256	>256
E3	F	4	2	2	4	8	3	4	3	>256	>256
E4	G	1	8	4	8	3	4	8	12	128	96
E5	H	4	2	4	2	12	3	6	3	12	>256
E6	A	4	2	1	8	6	3	2	8	48	>256
E7	I	8	8	2	16	8	8	4	>32	32	64
E10	A	4	1	1	2	4	1	4	1.5	12	>256
E11	A	2	8	2	8	8	8	3	6	8	>256
E12	I	32	32	8	>32	>32	32	8	>32	>256	>256
E13	J	4	4	1	8	8	3	3	4	24	256
E14	K	8	2	2	2	12	4	6	2	192	>256
E16	I	4	4	4	16	8	4	8	8	>256	>256
E18	A	4	4	0.5	8	3	4	8	6	24	>256
E19	A	8	8	8	16	16	6	16	16	128	>256
Connecticut isolates
F5483	A	2	0.25	0.5	1	2	0.38	0.5	0.5	8	>256
H1788	A	2	0.5	0.5	0.5	2	0.38	0.5	0.5	4	24
J0597	A	2	0.5	0.5	1	2	0.5	0.38	0.75	6	48
N3201	A	4	1	2	1	3	0.38	0.38	1.5	4	48
T9322	A	4	1	1	2	3	0.75	0.5	2	12	96
W3490	A	2	0.25	1	0.5	2	0.75	0.75	0.5	4	32

^aIPM, imipenem; MER, meropenem; DOR, doripenem; ETP, ertapenem; CAZ, ceftazidime; TZB, piperacillin-tazobactam.