Table 1.

O types, sources, and culture collections of the 252 Shiga toxin-producing E. coli isolates analyzed in the present study

O type	Source	No. of isolates	Culture collection
157	Human	25	PA Department of Health,a STEC Center at MSUb
157	Cattle	1	Andrew Bensonc
157	Other	1	Peter Fengd
26	Human	19	PA Department of Health
26	Cattle	20	Chitrita DebRoye
26	Other	3	Chitrita DebRoy
103	Human	20	PA Department of Health
103	Cattle	18	Chitrita DebRoy
103	Other	8	Chitrita DebRoy, Robert Mandrellf
111	Human	20	PA Department of Health, Robert Mandrell
111	Cattle	20	Chitrita DebRoy, Robert Mandrell
111	Other	3	Chitrita DebRoy, Robert Mandrell
45	Human	20	PA Department of Health, Robert Mandrell
45	Cattle	1	Robert Mandrell
121	Human	13	PA Department of Health
121	Cattle	1	Robert Mandrell
121	Other	3	Chitrita DebRoy, Robert Mandrell
145	Human	9	PA Department of Health
145	Cattle	4	Chitrita DebRoy, Robert Mandrell
Other	Human, cattle, other	43	Chitrita DebRoy

^aPA Department of Health, Bureau of Laboratories, The Pennsylvania Department of Health, Exton, PA.

^bSTEC Center, reference center to facilitate the study of Shiga toxin-producing Escherichia coli, Michigan State University, East Lansing, MI.

^cAndrew Benson, Food Science and Technology Department, University of Nebraska, Lincoln, NE.

^dPeter Feng, Center for Food Safety and Nutrition, Food and Drug Administration, College Park, MD.

^eChitrita DebRoy, E. coli Reference Center, The Pennsylvania State University, University Park, PA.

^fRobert Mandrell, Produce Safety and Microbiology Research Unit, WRRC, ARS, USDA, Albany, CA.