Table 1. STEC strains used in this study and their Stx2 production levels determined by HTRF and RPLA assay.

Strain	Serotype	Source	stx subtype	Stx2 titer		Accession No.	References
				HTRF (ng/ml)*	RPLA (unit/ml)†
Sakai	O157:H7	Human	stx1a/stx2a	9,900 ± 520	8,092	BA000007	Hayashi et al. (2001).
130549	O26:H11	Human	stx2a	34,000 ± 1,500	32,768	BDHP01000185	Ishijima et al. (2017).
11E007	O146:H21	Human	stx2b	330 ± 39	256	BOUS01000033	This study
SI-NP059	Onovel1:H16	Bovine	stx2b	1,500 ± 120	512	BGIA01000167	Arimizu et al. (2019).
WGPS6	O157:H7	Human	stx2c	2,700 ± 79	2,048	AP012539	Ogura et al. (2015).
5044	O145:H28	Human	stx2c	2,800 ± 160	2,048	BJPC01000106	Nakamura et al. (2020).
112808	O145:H28	Human	stx1a/stx2d	1,200 ± 400	1,024	BJQB01000217	Nakamura et al. (2020).
10E094	OUT:H7	Human	stx2d	85 ± 5	32	BOUT01000015	This study
EC-PM083	O157:H19	Swine	stx2e	640 ± 90	512	BOUQ01000003	This study
EC-PM098	O50:H32 or O2:H32	Swine	stx2e	100 ± 20	64	BOUR01000009	This study
07E033	O63:H6	Human	stx2f	N.D.	128	BOUS01000033	This study
KS-P022	O168:H8	Bovine	stx2g	890 ± 170	512	BGAG01000027	Arimizu et al. (2019).
MG1655	O16:H48	Widely used laboratory strain	stx-negative	N.D.	N.D.	U00096	Blattner et al. (1997).

Notes:

^*Technical triplicate (mean value ± SD).

^†1 unit/ml roughly corresponds to 1 ng/ml of Stx2a (see “Methods”)

UT, untypable.

N.D., not detected.