Table 4.

Antibiotic susceptibilities of E. coli expressing position 121 IMP-1 variants

Variant	MIC (μg/ml)
	Wild-type background		C221G background
	Ampicillin	Cefotaxime	Ampicillin	Cefotaxime
Wild type	125	250
C221G			6	4
S121A	>256	48	3	0.75
S121C	48	3	1.5	0.047
S121D	1	0.023	2	0.094
S121E	1.5	0.032	12	4
S121F	1.5	0.032	2	0.047
S121G	>256	32	3	0.19
S121H	1.5	0.023	2	0.047
S121I	1.5	0.064	1	0.023
S121K	1.5	0.032	2	0.047
S121L	1.5	0.032	1.5	0.032
S121 M	1.5	0.023	1.5	0.023
S121N	6	0.38	2	0.047
S121P	1	0.023	1.5	0.032
S121Q	4	0.047	1.5	0.032
S121R	2	0.032	2	0.047
S121T	3	2	48	4
S121V	8	1	2	0.094
S121W	1.5	0.032	1.5	0.032
S121Y	1.5	0.047	1.5	0.032