Table 1.

MIC range, MIC₅₀ (mg/L) and MIC₉₀ (mg/L) values of 21 antimicrobial agents for Ec-ESBL and Ec-MRnoB isolates, and percentages of resistant isolates to the indicated agents (EUCAST breakpoints, except where indicated)

	Ec-ESBL (N=100)				Ec-MRnoB (N=100)
Agent	Range	MIC50	MIC90	%R	Range	MIC50	MIC90	%R
Amoxicillin	64-≥256	≥256	≥256	100	2-≥256	≥256	≥256	99
Amoxicillin-Clavulanic acid	8-16	4	8	41	8-≥128	8	32	83
Piperacillin	32-≥64	≥64	≥64	100	≤16-≥64	≥64	≥64	84
Piperacillin-Tazobactam	≤0.5-≥256	4	16	16	≤0.25-≥256	2	4	6
Cefoxitina	≤2-32	≤2	8	5	≤2-≥32	4	8	8
Cefotetana	≤1-8	≤1	≤1	0	≤1-≥32	≤1	≤1	2
Cefotaxime	32-≥128	≥128	≥128	100	≤0.5-128	≤0.5	≤0.5	5
Ceftazidime	≤0.5-≥128	2	16	23	≤0.5-128	≤0.5	≤0.5	8
Cefepime	≤1-≥32	≥32	≥32	96	≤1-4	≤1	<1	1
Aztreonam	2-≥64	16	≥64	96	≤0.5-32	≤0.5	≤0.5	6
Imipenem	≤0.5-1	≤0.5	≤0.5	0	≤0.5-2	≤0.5	≤0.5	0
Meropenem	≤0.5	≤0.5	≤0.5	0	≤0.5	≤0.5	≤0.5	0
Gentamicin	≤0.5-≥256	1	32	19	0.5-≥256	64	256	96
Tobramycin	0.5-256	1	8	17	≤0.25-256	8	32	89
Amikacin	≤0.5-8	2	4	0	1-8	2	4	0
Nalidixic acida	1-≥256	≥256	≥256	89	1-≥256	≥256	≥256	98
Ciprofloxacina	≤0.5-≥256	16	128	74	≤0.25-≥256	32	128	93
Tetracyclinea	0.5-≥256	256	256	80	≤0.25-256	256	256	84
Doxycyclinea	≤0.5-128	16	64	76	≤0.25-128	32	64	79
Tigecyclineb	≤0.5-1	≤0.5	≤0.5	0	≤0.25-0.5	≤0.25	≤0.25	0
Trimethoprim-Sulfamethoxazole	≤0.5-≥32	≥32/608	≥32/608	67	≤0.5-≥32	≥32/608	≥32/608	98

^a CLSI 2011 breakpoints. ^b FDA breakpoints.