Table 3.

MICs (μg ml⁻¹) for 82 E. coli isolates with ESBL and/or AmpC enzymes

Type of β-lactamase (no. of isolates)	FOX			CAZ			CAZ–CA*			CTX			CTX–CA*
	Range	MIC50	MIC90	Range	MIC50	MIC90	Range	MIC50	MIC90	Range	MIC50	MIC90	Range	MIC50	MIC90
CTX-M-3 (10)	4–32	8	32	2–32	4	32	0.3–1	1	1	16–>256	128	>256	0.1–1	0.3	1
CTX-M-12+DHA-1 (1)	256			256			128			64			32
CTX-M-15 (24)	4–64	16	32	16–>256	64	>256	0.3–4	1	4	128–>256	>256	>256	0.1–1	0.5	1
CTX-M-15+DHA-1 (1)	128			64			2			>256			1
CTX-M-15+CMY-2 (1)	256			64			64			>256			32
CTX-M-15+CMY-10 (1)	>256			64			16			256			128
CTX-M-22 (1)	2			1			0.1			32			0.1
CTX-M-22+DHA-1 (1)	256			32			2			32			1
CTX-M-57 (1)	64			32			1			256			0.3
CTX-M-57+DHA-1 (1)	256			64			8			256			2
CTX-M-9 (1)	4			1			0.3			32			0.1
CTX-M-9+DHA-1 (1)	128			2			1			>256			0.5
CTX-M-14 (30)	2–128	16	64	0.3–16	2	8	0.1–2	1	2	16–>256	128	256	0.1–1	0.5	1
CTX-M-14+SHV-12 (1)	16			256			1			64			0.1
CTX-M-14+CMY-2 (1)	256			64			64			128			32
CTX-M-27 (1)	16			256			1			>256			0.3
SHV-12+DHA-1 (1)	>256			64			8			16			4
DHA-1 (4)	16–256			0.1–32			0.1–8			0.1–32			0.1–8
CMY-2 (1)	256			16			16			16			32
CMY-11 (1)	>256			16			16			128			128

*CA at a fixed concentration of 4 μg ml⁻¹.