TABLE 1.

MICs of β-lactams for clinical strain AJC68081, E. coli TG1, E. coli TG1 (pBE-1), and E. coli TG1 (pGER1)

Antibiotic	MIC (μg/ml)a
	AJC68081 (produces AmpC of AG3)	E. coli TG1	E. coli TG1 (pBE-1)b	E. coli TG1 (pGER1)c
Amoxicillin	>256	3	256	128
Amoxicillin + clavulanated	6	2	24	32
Piperacillin	>256	0.38	64	8
Cephalothin	>256	3	>256	>256
Cefuroxime	>256	1.5	>256	>256
Cefoxitin	>256	2	128	2
Cefotaxime	256	0.023	2	4
Cefotaxime + clavulanated	0.19	0.023	1	1
Ceftazidime	32	0.064	0.75	16
Ceftazidime + clavulanated	0.19	0.064	0.5	8
Cefepime	32	0.016	0.047	0.25
Aztreonam	12	0.032	0.25	1
Imipenem	1	0.125	0.38	0.125
Meropenem	0.75	0.008	0.023	0.012
Clavulanic acid	8-16	ND	ND	ND
Sulbactam	16-32	ND	ND	ND

^aND, not done.

^bTransformant producing AmpC β-lactamase of AG3.

^cTransformant producing AmpC β-lactamase of A. baumannii.

^dClavulanate was used at 4 μg/ml.