TABLE 4.

MICs of ampC alleles from clinical isolates

ampC allele	AmpC amino acid substitutionsa	MIC in μg/ml (fold change relative to WT AmpC) of:
		E. coli DH5α						ΔampC MPAO1
		Aztreonam	Ampicillin	Ceftazidime	Cefpirome	Meropenem	Imipenem	Aztreonam	Ampicillin	Ceftazidime	Cefpirome	Meropenem	Imipenem
None	Empty vector	0.0625	2	0.125	0.0078125	0.0625	1	2	64	1	1	4	1
Wild type	None	0.25	64	0.5	0.015625	0.0625	1	16	1,024	16	8	4	4
1	P7S, T105A, G242S, N347S	1 (4)	32 (0.5)	2 (4)	0.015625 (1)	0.0625 (1)	1 (1)	128 (8)	2,048 (2)	128 (8)	16 (2)	4 (1)	2 (0.5)
2	G27D, R79Q, T105A, G242S	0.5 (2)	32 (0.5)	0.5 (1)	0.0078125 (0.5)	0.0625 (1)	1 (1)	64 (4)	2,048 (2)	64 (4)	16 (2)	4 (1)	2 (0.5)
3	T105A, G242S	0.5 (2)	16 (0.25)	1 (2)	0.015625 (1)	0.0625 (1)	2 (2)	32 (2)	2,048 (2)	64 (4)	16 (2)	4 (1)	2 (0.5)
4	R79Q, T105A, Q152R, Q157R, V239A, N347S	4 (16)	32 (0.5)	4 (8)	0.015625 (1)	0.0625 (1)	0.5 (0.5)	256 (16)	2,048 (2)	256 (16)	32 (4)	4 (1)	4 (1)
5	T105A, G242_P243insG	0.5 (2)	32 (0.5)	2 (4)	0.015625 (1)	0.0625 (1)	1 (1)	32 (2)	2,048 (2)	64 (4)	32 (4)	4 (1)	2 (0.5)
6	R79Q, T105A, V239A, D245G	16 (64)	256 (4)	16 (32)	0.0625 (4)	0.0625 (1)	1 (1)	256 (16)	2,048 (2)	256 (16)	32 (4)	4 (1)	2 (0.5)
7	T105A, L176R, V239A	1 (4)	64 (1)	2 (4)	0.015625 (1)	0.0625 (1)	1 (1)	32 (2)	2,048 (2)	64 (4)	16 (2)	4 (1)	2 (0.5)
8	T21A, T105A, Q174R, G391A	0.0625 (0.25)	2 (0.03125)	0.125 (0.25)	0.0078125 (0.5)	0.0625 (1)	1 (1)	2 (0.125)	32 (0.03125)	2 (0.125)	1 (0.125)	4 (1)	2 (0.5)
9	R79Q, T105A, V239A, P274L	0.5 (2)	64 (1)	1 (2)	0.015625 (1)	0.0625 (1)	1 (1)	32 (2)	2,048 (2)	128 (8)	16 (2)	4 (1)	4 (1)
10	T105A, V239A	1 (4)	128 (2)	1 (2)	0.015625 (1)	0.0625 (1)	1 (1)	64 (4)	2,048 (2)	64 (4)	16 (2)	4 (1)	4 (1)
11	R79Q, T105A, G242S, V356I	0.5 (2)	64 (1)	1 (2)	0.015625 (1)	0.0625 (1)	1 (1)	32 (2)	1,024 (1)	64 (4)	8 (1)	4 (1)	4 (1)

^aBoldface font indicates de novo mutation.