Table 2.

Results for susceptibility tests and MICs for E. coli strains (n = 550) isolated from 30 county hospitals

	All isolates (n = 550)				ESBL-positive (phenotype) isolates (n = 249)
Antibiotic	MIC50 (mg/L)	MIC90 (mg/L)	Susceptible %	Resistant %	MIC50 (mg/L)	MIC90 (mg/L)	Susceptible %	Resistant %
Ampicillin	256	>256	13.6	85.1	>256	>256	0	100
Piperacillin	64	>256	31.8	49.5	256	>256	0	91
Ampicillin-Sulbactam	16	64	35	39.1	32	64	14.7	61.5
Piperacillin-tazobactam	8	16	91	2.1	8	32	86.5	4.5
Cefazolin	32	256	46.7	51.1	256	256	0.4	99.6
Cefuroxime	8	256	50.1	47.8	256	256	0	98.5
Ceftazidime	0.5	32	80.4	18.3	4	64	55.6	40.6
Ceftriaxone	0.25	128	55.4	44.2	64	128	0.7	98.5
Cefepime	1	32	77.7	13.5	8	64	54.5	28.9
Cefoxitin	4	32	76.9	15	8	128	61.8	24.7
Biapenem	0.064	0.125	100	0	0.064	0.125	100	0
Imipenem	0.125	0.25	100	0	0.125	0.25	100	0
Meropenem	0.064	0.125	100	0	0.064	0.125	100	0
Amikacin	2	8	93.6	6.1	2	64	89.1	10.2
Gentamicin	16	128	47.2	51.5	64	256	33.5	66.2
Ciprofloxacin	4	64	46.7	51	32	128	24.8	73.3
Levofloxacin	4	32	49.1	46.7	16	64	26.2	68.9
Fosfomycin	1	32	94.1	5.1	1	128	88.6	9.8