TABLE 1.

MICs of β-lactam antibiotics and sizes of β-lactamase-encoding plasmids for Klebsiella outbreak strains and their E. coli transconjugants

Strain	MICs (μg/ml) ofa:													β-Lactamase-encoding plasmids (kb)
	Ampicillin	Amox + Clav (2)	Amox + Clav (2:1)	Pip	Pip + Taz (4)	Temocillin	Ceftaz	Ceftaz + Clav (2)	Cefotaxime	Cefepime	Cefoxitin	Imipenem	Meropenem
D1	>4,096	16	16	512	4	8	>64	1	1	4	2	0.25	0.06	78
D1 transconjugant	4,096	16					>64	1	1		4
D2	>4,096	32	16	512	128	16	32	1	16	16	32	0.06	0.06	70
D2 transconjugant	2,048	4					2	0.25	2		4
D3	4,096	8	4	128	4	8	64	0.5	16	2	16	0.06	0.06	130
D3 transconjugant	4,096	4					64	0.25	16		4
D4	>4,096	64	8	512	128	8	>64	0.5	64	8	16	0.06	0.03	150
D4 transconjugant	>4,096	16					16	0.5	32		8
D5	4,096	8	8	256	2	4	16	0.5	8	1	4	0.06	0.03	85
D5 transconjugant	2,048	8					16	0.5	16		8
D6	>4,096	8	8	256	32	4	>64	0.5	8	2	4	0.06	0.06	125
D6 transconjugant	4,096	8					>64	0.5	16		16
D7	>4,096	256	32	>512	128	8	>64	1	16	1	8	0.06	0.03	125
D7 transconjugant	1,024	4					16	0.25	2		4
D8	4,096	8	8	128	4	4	8	0.5	4	0.5	8	0.06	0.03	150
D8 transconjugant	>4,096	16					8	0.5	16		4
D9	>4,096	64	32	512	128	16	64	2	32	8	16	0.25	0.06	160
D9 transconjugant	>4,096	16					32	1	32		4
D10	1,024	4	4	64	2	≤2	32	0.25	2	0.5	2	0.12	0.03	150
D10 transconjugant	512	4					32	0.25	1		4

^aAntibiotic abbreviations: Amox, amoxicillin; Clav, clavulanic acid; Pip, piperacillin; Taz, tazobactam; Ceftaz, ceftazidime.