TABLE 1.

Plasmid sizes and MICs of β-lactam antimicrobials for E. coli isolates, transconjugants, transformants, and the recipient strains

Strain	MIC (μg/ml) of drugc:												Plasmid size(s) (kb)
	AMP	AMP-CA	PIP	ATM	IPM	MPM	FOX	CAZ	CAZ-CA	CTX	CPM	MOX
69	4,096	4,096	1,024	256	0.5	0.25	1,024	512	256	512	8	32	3, 5.5, 7, 30, 45
68	1,024	512	256	64	4	2	512	64	64	64	2	256	3, 5.5, 7, 30, 45
79	>4,096	>4,096	1,024	512	64	16	>1,024	1,024	1,024	1,024	32	>1,024	3, 5.5, 7, 30, 45
79-rev	4,096	ND	512	ND	0.5	ND	256	1,024	ND	128	2	16	3, 5.5, 7, 30, 45
69-tca	2,048	2,048	512	128	0.5	≤0.06	256	256	256	128	2	16	5.5, 7, 30, 45
68-tca	256	256	32	16	0.5	≤0.06	32	32	16	8	0.25	2	5.5, 7, 45
79-tca	2,048	2,048	512	128	0.5	0.12	256	512	256	128	4	16	5.5, 7, 45
69-tfb	64	ND	4	ND	0.12	ND	32	8	ND	4	0.12	2	7
68-tfb	64	ND	4	ND	0.12	ND	32	8	ND	4	0.12	2	7
79-tfb	4,096	ND	256	ND	0.25	ND	128	512	ND	128	2	16	7, 45
J62.1	8	8	4	0.12	0.25	≤0.06	4	0.25	0.12	≤0.06	≤0.06	0.25
XL-1 Blue	4	ND	≤1	ND	0.12	ND	4	0.25	ND	≤0.06	≤0.06	0.25

^aTransconjugant in E. coli J62.1. 

^bTransformant in E. coli XL-1 Blue. 

^cAbbreviations: AMP, ampicillin; AMP-CA, ampicillin-clavulanate (2 μg/ml); PIP, piperacillin; ATM, aztreonam; IPM, imipenem; MPM, meropenem; FOX, cefoxitin; CAZ, ceftazidime; CAZ-CA, ceftazidime-clavulanate (2 μg/ml); CTX, cefotaxime; CPM, cefepime; MOX, moxalactam; ND, not determined.