TABLE 1.

Bacterial strains used in this study and MICs of CAZ and CTX with or without β-lactamase inhibitors

Strain	β-Lactamase	MIC (μg/ml)								Reference
		CAZ	CAZ + CLA	CAZ + SMA	CAZ + APB	CTX	CTX + CLA	CTX + SMA	CTX + APB
E. coli NS12	CMY-2	128	64	128	4	64	32	64	2	This study
E. coli HKY515	CMY-2	256	128	256	4	64	32	64	4	This study
E. coli HKY701	CMY-2	128	128	128	2	32	32	64	4	This study
E. coli MRY041197	CMY-2	>256	256	>256	8	128	128	128	8	This study
E. coli HKY581	CMY-2	256	128	256	8	128	128	256	4	This study
E. coli C502	CMY-2	256	256	256	16	16	32	32	2	This study
E. coli KG2	CMY-2	128	128	64	4	64	32	64	8	This study
E. coli MRY041243	CMY-8	256	256	>256	4	64	32	64	0.5	This study
E. coli M68	CMY-9	256	256	256	1	>256	>256	>256	16	10
E. coli Coral Gables 66040	FOX-5	>128	>128	>128	4	64	64	64	1	G. A. Jacoby
E. coli Coral J53 (a trans- formant)	ACT-1	8	4	4	≤0.25	2	2	2	≤0.25	G. A. Jacoby
E. coli HKY28	Mutant AmpC	64	32	64	4	16	4	8	1	11
K. pneumoniae NU2936	MOX-1	64	32	32	0.5	256	256	256	8	15
K. pneumoniae HKY-L1	MOX-1	32	32	32	1	128	128	128	4	This study
K. pneumoniae KPW142	CMY-8	32	32	64	1	128	128	128	4	This study
K. pneumoniae HKY209	CMY-9	>128	>128	>128	2	>128	>128	>128	2	This study
K. pneumoniae HKY327	CMY-19	>256	>256	>256	16	64	64	64	1	This study
K. pneumoniae 5064	FOX-5	64	64	64	2	8	16	16	0.5	36
K. pneumoniae Bronx Lebanon 18	ACT-1	64	64	128	64	8	16	8	0.5	G. A. Jacoby
K. pneumoniae P20	LAT-1	64	64	64	2	32	32	32	1	40
Hafnia alvei EE47a	AmpC	64	128	64	2	32	64	32	2	This study
E. coli NCB03522b	CMY-2 + CTX-M-9	64	16	64	16	256	8	256	256	This study
K. pneumoniae NCB02189a	DHA-1 + CTX-M-9	16	128	16	1	32	8	32	2	This study
E. coli AYW-1	TEM-26	>128	0.5	>128	>128	2	<0.06	2	2	44
E. coli HKY322	TEM-91	128	0.5	128	>128	1	<0.06	1	1	18
E. coli MRY041435	TEM-132	64	1	64	64	8	≤0.25	4	4	This study
E. coli HKY453	SHV-24	>128	2	>128	>128	2	0.13	2	2	17
E. coli NCB03515	CTX-M-3	32	≤0.25	16	16	>256	≤0.25	256	256	This study
E. coli MRY04718	CTX-M-3	64	1	128	32	>256	≤0.25	>256	>256	This study
E. coli AYW-2	CTX-M-2	8	0.13	8	4	>128	<0.06	>128	>128	This study
E. coli NCB03490	CTX-M-2	4	≤0.25	4	1	128	≤0.25	256	64	This study
E. coli NCB03520	CTX-M-14	2	0.25	4	1	128	0.13	>128	128	This study
E. coli AYW-3	CTX-M-9	0.5	<0.06	0.5	0.25	32	<0.06	64	16	This study
K. pneumoniae HKY402	SHV-12	>128	1	>128	>128	32	<0.06	32	32	44
K. pneumoniae MRY041410	TEM-132	64	1	64	64	4	≤0.25	4	8	This study
K. pneumoniae K108	CTX-M-1	2	0.25	1	2	64	<0.06	64	64	This study
K. pneumoniae MRY04332	CTX-M-3	16	1	8	8	128	≤0.25	128	128	This study
K. pneumoniae HKY495	CTX-M-2	16	1	16	16	128	0.13	>128	>128	This study
K. pneumoniae MRY04504	CTX-M-2	2	≤0.25	2	4	64	≤0.25	128	64	This study
K. pneumoniae NCB03502	CTX-M-9	0.5	0.06	1	1	32	<0.06	64	32	This study
K. pneumoniae NCB03081	CTX-M-9	4	≤0.25	4	4	32	≤0.25	32	32	This study
K. pneumoniae KG525	GES-3J	>128	>128	>128	>128	64	8	64	32	42
K. pneumoniae KG502	GES-4J	>128	>128	>128	>128	32	16	16	16	43
E. coli NCB03426	IMP-1	64	64	≤0.25	64	16	16	≤0.25	16	This study
E. coli NCB02465	IMP-1	128	128	≤0.25	128	32	64	≤0.25	64	This study
K. pneumoniae KP115	IMP-1	>128	128	1	>128	64	64	0.25	64	This study
K. pneumoniae NCB03034	IMP-1	64	64	≤0.25	64	128	128	≤0.25	128	This study
E. coli EE61	OXA-30	2	2	2	2	4	4	4	4	This study

^aProduction of AmpC or DHA-1 might be augmented in the presence of clavulanic acid.

^bE. coli strain NCB03522 also produces the TEM-1 penicillinase.