TABLE 2.

Sensitivity of the E. coli PhoU mutant (JHU-313) and the complemented strain to antibiotics and peroxide as measured by zone of inhibition^a

Antibiotic	Concentration (μg/ml)	Inhibition zone size (mm) of indicated strain
		W3110	JHU-313	JHU-313 containing pPhoU	JHU-313 containing pVector
Ampicillin	100	35	40	40	45
	25	28	35	36	40
	6	25	30	32	34
	1.5	21	25	25	27
Gentamicin	10	25	27	28	31
	2	22	26	24	30
	0.5	20	22	22	29
	0.1	14	20	17	22
Tetracycline	50	23	32	32	34
	25	23	32	32	34
	12.5	22	26	30	34
Trimethoprim	2	30	42	36	44
	1	26	38	33	40
	0.5	24	31	32	36
Norfloxacin	4	32	37	36	44
	2	30	34	35	40
	0.5	27	30	31	35
	0.1	24	28	27	29
Hydrogen peroxide (30%)		30	37	39	46

^aThe sensitivity of bacterial strains to antibiotics or peroxide was determined by Kirby-Bauer's method.