TABLE 2.

Characteristics of phages from clinical E. coli O157:H7 isolates

Strain and phage	Uninduceda	Ciprofloxacin inductionb		Mitomycin C inductionc
		Lysis (OD)d	Stx or GFP concn	Lysis (OD)	Stx or GFP concn
E. coli O157:H7
PT22	27e	0.238	347e	0.507	975e
PT27	23	0.409	354	0.340	588
PT32	24	0.430	426	0.534	886
PT38a	18	0.395	355	0.618	942
PT38b	19	0.376	352	0.520	1127
PT39a	24	0.469	364	0.558	1119
C600 lysogens (Stx2 deleted)
φPT22Δtox	0.05f	0.226	41f	0.845	59f
φPT27Δtox	NDg	0.209	51	0.690	49
φPT32Δtox	ND	0.243	33	0.845	67
φPT38aΔtox	ND	0.430	49	0.570	51
φPT38bΔtox	ND	0.825	79	0.855	21
φPT39aΔtox	ND	0.430	72	1.460	28

^aStrains were grown overnight in LB broth at 37°C with shaking.

^bStrains were induced with 30 ng of ciprofloxacin/ml for 16 h at 37°C with shaking.

^cStrains were induced with 0.5 μg of mitomycin C/ml for 16 h at 37°C with shaking.

^dLysis was assessed by measuring the OD₆₀₀ after 16 h induction at 37°C with shaking, in the presence of ciprofloxacin or mitomycin C. Results in this trial are representative of the trends observed in at least one other trial.

^eStx concentration (in micrograms per milliliter) from the E. coli O157:H7 strains was measured by ELISA.

^fGFP production from the C600 lysogens was determined by Western analysis, and bands within a strain were compared using ImageQuant. Results for uninduced, ciprofloxacin-induced, and mitomycin C-induced samples are reported as the percentage of the total volume of the bands for each strain.

^gND, not detected.