Table 1.

MIC values (μg/mL) of E. coli DH10B Expressing SHV-1 and Asn276 Variants^a

	ampicillin	piperacillin	cephalothin	ampicillin/clavulanate	ampicillin/sulbactam	ampicillin/tazobactam
DH10B	1	1	4	0.06	0.06	0.06
SHV-1	> 16384	2048	64–128	2	512	64
Asn276Asp	8192	512	8–16	8	256	64
Asn276Gly	4096	256	16	2	64	16
Asn276Ser	4096	512	16	1	32–64	16
Asn276Val	2048	512	16	0.5	256	32
Asn276Thr	1024–2048	128–256	8–16	1	32	8
Asn276Gln, -Glu, -Cys	1024–2048	64–128	8–16	0.5	64–128	8
Asn276His	1024	256	16	1	128	16
Asn276Ala, -Leu, -Ile	256–512	16–32	4–8	0.25–0.5	8–16	2
Asn276Lys, -Arg, -Tyr, -Phe	64	8–16	4-8	0.125–0.25	1–4	0.5–1
Asn276Met	32	4	4	0.06	0.06	0.06
Asn276Pro, -Trp	8–16	2–4	4–8	0.06	0.06	0.06

^aInhibitors were evaluated in the presence of 50 μg/mL ampicillin.