TABLE 1.

MICs of different β-lactams against a collection of 94 strains (93 clinical isolates and ATCC 13047) of ECC according to resistance phenotypes

ECC clinical isolate (no.)	MIC (mg/liter)			EUCAST susceptibility breakpoint (mg/liter)	Susceptible strains (%)
	MIC50	MIC90	Range
All (94)
Ceftolozane-tazobactam	1	16	0.12–128	≤1	51
Imipenem	0.25	0.5	0.12–4	≤2	99
Ertapenem	0.25	2	0.01–32	≤0.5	70
Cefepime	0.5	16	0.03–>256	≤1	54
Ceftazidime	64	256	0.25–>256	≤1	33
Cefotaxime	64	>256	0.25–>256	≤1	34
Ceftriaxone	128	>256	0.25–>256	≤1	34
Piperacillin-tazobactam	64	256	2–256	≤8	37
Wild type (32)
Ceftolozane-tazobactam	0.25	0.5	0.12–0.5	≤1	100
Imipenem	0.25	0.5	0.12–0.5	≤2	100
Ertapenem	0.06	0.12	0.01–0.25	≤0.5	100
Cefepime	0.03	0.06	0.03–0.06	≤1	100
Ceftazidime	0.5	1	0.25–2	≤1	97
Cefotaxime	0.5	1	0.25–1	≤1	100
Ceftriaxone	0.5	1	0.25–1	≤1	100
Piperacillin-tazobactam	2	4	2–8	≤8	100
ESBL alone (9)
Ceftolozane-tazobactam	1	2	0.25–4	≤1	67
Imipenem	0.25	0.5	0.12–0.5	≤2	100
Ertapenem	0.125	0.5	0.03–1	≤0.5	89
Cefepime	4	256	0.06–64	≤1	44
Ceftazidime	64	128	32–128	≤1	0
Cefotaxime	256	>256	4–>256	≤1	0
Ceftriaxone	256	>256	2–>256	≤1	0
Piperacillin-tazobactam	64	128	8–128	≤8	22
ESBL+HL-CASE (19)
Ceftolozane-tazobactam	8	128	1–128	≤1	11
Imipenem	0.5	1	0.25–4	≤2	95
Ertapenem	0.5	8	0.12–32	≤0.5	53
Cefepime	4	256	0.12–>256	≤1	11
Ceftazidime	128	256	32–>256	≤1	0
Cefotaxime	256	>256	64–>256	≤1	0
Ceftriaxone	256	>256	128–>256	≤1	0
Piperacillin-tazobactam	128	256	32–>256	≤8	0
HL-CASE (34)
Ceftolozane-tazobactam	4	16	0.25–32	≤1	24
Imipenem	0.25	0.5	0.12–1	≤2	100
Ertapenem	1	2	0.03–4	≤0.5	47
Cefepime	2	8	0.12–16	≤1	35
Ceftazidime	128	256	2–>256	≤1	0
Cefotaxime	256	>256	16–>256	≤1	0
Ceftriaxone	256	>256	32–>256	≤1	0
Piperacillin-tazobactam	128	256	8–256	≤8	3