TABLE 2.

MICs of antibiotics for E. coli Lo, transconjugant E. coli J53/pQR1, and E. coli J53 Az

Antibiotic(s)	MIC (μg/ml)
Antibiotic(s)	E. coli Lo^a	E. coli J53/pQR1	E. coli J53
Nalidixic acid	>256	32	4
Ofloxacin	4	1	0.12
Ciprofloxacin	1	0.25	0.01
Moxifloxacin	2	0.5	0.03
Sparfloxacin	4	1	0.01
Rifampin	>256	32	8
Chloramphenicol	32	32	4
Gentamicin	16	8	0.12
Tobramycin	128	64	0.12
Streptomycin	>256	>256	2
Amikacin	16	8	0.25
Sulfamethoxazole	>512	>512	0.12
Trimethoprim	>512	>512	0.12
Tetracycline	>64	1	1
Amoxicillin	>512	>512	4
Amoxicillin-CLA^b	128	32	4
Ticarcillin	>512	>512	4
Ticarcillin-CLA	256	4	4
Piperacillin	128	16	2
Piperacillin-TZB^c	4	2	1
Cephalothin	128	128	8
Cefoxitin	4	2	2
Cefotaxime	4	4	0.06
Ceftazidime	256	256	0.06
Ceftazidime + CLA	0.25	0.25	0.06
Aztreonam	32	32	0.06
Cefepime	1	1	0.01
Imipenem	0.25	0.25	0.06

↵a E. coli Lo and E. coli J53/pQR1 contained the qnr-positive plasmid that also harbored the bla_VEB-1 gene.
↵b CLA, clavulanic acid at 2 μg/ml.
↵c TZB, tazobactam at 4 μg/ml.