TABLE 2.

Susceptibilities of E. coli DH5α strains to different combinations of antibiotics and inhibitors

E. coli strain	Amino acid at the following codon positions:			MIC (μg/ml)a
	216	217	218	Carb + SLB	Amp + SLB	Carb + CLV	Amp + CLV	Carb + TZB	Amp + TZB
DH5α				<10	<10	2	2	8	8
ATCC 25922				<10	<10	16	4	32	16
DH5α(pBGS19+)b				<10	<10	2	2	16	16
DH5α(pMON711) (wild type)	V	T	G	2,500	156	500	16	1,000	500
DH5α mutants
pMON77020	G	A	G	625	156	63	8	500	250
pMON77021	V	A	G	1,250	156	250	31	500	250
pMON77022	G	S	G	1,250	156	63	8	500	250
pMON77023	G	S	R	625	156	63	8	500	125
pMON77024	G	T	S	1,250	156	ND	ND	250	125
pMON77025	G	S	A	1,250	156	63	8	500	250
pMON77026	V	S	A	1,250	156	500	31	500	250
pMON77028	R	T	G	2,500	156	63	4	1,000	250
pMON77029	A	S	S	2,500	313	250	31	500	250
pMON77030	A	S	Q	2,500	313	500	31	500	250
pMON77031	S	A	R	2,500	625	63	8	500	250
pMON77033	A	S	H	1,250	156	250	31	250	125

^aAbbreviations: Carb, carbenicillin; Amp, ampicillin; SLB, sulbactam; TZB, tazobactam; CLV, clavulanic acid. ND, not determined. Sulbactam, clavulanic acid, and tazobactam were each used at 8 μg/ml. 

^bE. coli DH5α strain containing the pBGS19⁺ vector only.