TABLE 2.

XbaI-PFGE profiles of wild-type STEC O157:H7 strains and their derived isolates revived after prolonged storage at room temperature for a total period of 25 weeks, with subcultures performed at every 5-week interval

Strain and PFGE profile	Typical no. of fragment differences from original pattern	No. of colonies showing identity to PFGE profile following storage for no. of wks:
		Presubculture	0	5	10	15	20	25
RIMD0509952
I-a	0a	9	14	14	14	14	11	14
I-b	2	5	0	0	0	0	0	0
I-d	1	0	0	0	0	0	1	0
I-e	1	0	0	0	0	0	1	0
I-f	2	0	0	0	0	0	1	0
EC1015
II-a	0a	6b	13	9	8	0	9	9
II-b	2	5c	1	0	0	0	0	0
II-c	1	3	0	0	0	0	0	0
II-d	1	0	0	4	6	3	2	3
II-h	2	0	0	1	0	0	0	0
II-i	4	0	0	0	0	1	0	0
II-j	6	0	0	0	0	2	0	0
II-k	5	0	0	0	0	6	1	0
II-l	2	0	0	0	0	1	0	0
II-m	5	0	0	0	0	1	0	0
II-n	3	0	0	0	0	0	1	0
II-o	2	0	0	0	0	0	1	0
II-p	4	0	0	0	0	0	0	1
II-q	3	0	0	0	0	0	0	1
83-1386
III-a	0a	10	14	13	14	14	10	14
III-b	2	2	0	0	0	0	0	0
III-c	3	1	0	0	0	0	0	0
III-d	3	1	0	0	0	0	0	0
III-f	1	0	0	1	0	0	0	0
III-g	1	0	0	0	0	0	4	0

^aOriginal pattern.

^bOne of the 6 strains did not contain the stx2 gene.

^cOne of the 5 strains did not contain the stx2 gene.