Table 5. Comparison of O-types and colony colors among STEC.

				Number of isolates by O-typea
Indicator agar	Colony morphology		O26		O45	O91	O103	O111	O113	O121	O145	O157
C-O157	pink	Ab	1		0	0	0	0	0	0	0	37
C-O157	blue w/white perimeter	B	40 c		0	5	0	0	18	5	0	0
C-O157	blue w/pink perimeter	C	1		0	0	17	0	0	0	0	0
C-O157	blue, white perimeter, blue halo	D	0		10	0	0	0	0	0	0	0
C-O157	turquoise	E	0		0	0	0	0	1	1	4	0
C-O157	bluish turquoise, swarmy	F	0		0	0	0	0	6	0	0	0
C-O157	pink w/blue center	G	0		0	0	0	12	0	0	0	1
C-O157	white w/blue center	H	0		0	0	0	0	0	0	7	0
NT-RA	purple	I	38		0	0	0	0	0	0	4	0
NT-RA	bluish purple	J	0		0	0	0	0	0	0	0	1
NT-RA	pink	K	1		0	0	0	0	6	2	2	0
NT-RA	violet	L	1		0	0	0	0	0	0	0	0
NT-RA	grayish pink	M	0		0	0	17	0	0	0	0	0
NT-RA	steel gray	N	0		0	0	0	0	0	0	0	35
NT-RA	grayish purple	O	1		0	0	0	0	0	0	7	0
NT-RA	grayish blue	P	1		0	0	0	12	0	0	0	0
NT-RA	white w/gray center	Q	0		0	0	0	0	0	0	0	2
NT-RA	no growth		0		10	5	0	0	19	4	0	0
Total number			42		10	5	17	12	25	6	11	38

^aSerotyped STEC isolates were streaked for single colonies on C-O157 or NT-RA and colony morphology of each were categorized into groups based on both color and colony shape.

^bLetter designation refers to Figure 2.

^cBoldface numbers indicate most common colony characteristics for each O-type on the indicator agar.