TABLE 1.

E. coli strains used in this study and analysis of their virulence characteristics^a

Strain no.	Serotype	Detailsb (reference)	Animal species	Clinical symptom(s)	Toxin produced	Virulence determinant(s)	Designationc
E33167	O26:K60	PHLS, London	Human	Not known	VT	hlyA, eae β	Atypical EHEC
EC537/01	O26:K60	Winswick	Bovine	Not known	VT	hlyA, eae β	Atypical EHEC
EC1840/00	O26:K60	Barnow Gurney (Langford)	Bovine	Diarrhea	VT	hlyA, eae β	Atypical EHEC
EC172/00	O26:K60	Langford	Bovine	Collapsed, dehydrated	VT	hlyA, eae β	Atypical EHEC
EC1722/00	O26:K60	Langford	Bovine	Diarrhea	VT	hlyA, eae β	Atypical EHEC
EC183/99	O26:K60	Preston	Bovine	Diarrhea	VT	hlyA, eae β	Atypical EPEC
EC681/99	O26:K60	Penrith	Ovine	Routine survey	VT	hlyA, eae β	Atypical EPEC
EC335/98	O26:K60	Sweden	Ovine	Diarrhea	None	hlyA, eae β	Atypical EPEC
EC38/99	O26:K60	Penrith	Bovine	Diarrhea	None	eae β	Atypical EPEC
EC622/99	O26:K60	Winchester	Porcine	Routine survey	None	eae β	Atypical EPEC
EC225/00	O26:K60	Powys (Wales)	Bovine	Dysentry	None	hlyA, eae β	Atypical EPEC
EC459/01	O26:K60	Haverford West (Carmarthen)	Bovine	Mastitis	None	eae β	Atypical EPEC
EC1725/00	O26:K60	Kirby Moorside (Thirsk)	Bovine	Diarrhea, runny nose	None	eae β	Atypical EPEC
EC1388/00	O26:K60	Aberyswyth	Ovine	Nephrosis	None	eae β	Atypical EPEC
EC720/98	Untypeable	Sutton Bonington	Bovine	Healthy	VT	hlyA, eae β	Atypical EHEC
EC370/98	O86:K61	Inverness	Avian (migrating)	Dead	CLDT	eae γ	Atypical EPEC
EC558/00	O86:K61	Inverness	Avian (migrating)	Dead	CLDT	eae γ, eae δ	Atypical EPEC
EC157/99	O157:H7	Thirsk	Bovine	0157 tracebackd	VT	hlyA, eae γ	Typical EHEC
EDL933	O157:H7	Sequenced strain (29)			VT	hlyA, eae γ	Typical EHEC
E140065	O157:H7	PHLS, London	Human	Not known	VT	hlyA, eae γ	Typical EHEC
E139229	O157:H7	PHLS, London	Human	Not known	VT	hlyA, eae γ	Typical EHEC
EC1727/00	O55:K+	Langford	Bovine	Diarrhoea	None	None	Neither
SO55	O55:K+		O antigen strain collection, Weybridge		None	hlyA, eae β	Atypical EPEC
SO111	O111:K+		O antigen strain collection, Weybridge		None	bfp, eae β, eae δ	Typical EPEC
SO126	O126:K+		O antigen strain collection, Weybridge		None	eae β	Atypical EPEC
SO29	O29:K+		O antigen strain collection, Weybridge		None	None	Neither
GC4468	K-12 Δ(argF-lac)169 IN(rrnD-rrnE)1 rpsL179	Lab strain (31)
KL773	K-12 Δ(gpt-lac)5 Δ(galK-bioD)76 rpsL171 metE70	Lab strain (6)
MG1655	K-12	Sequenced strain (4)

^aThe serotype, geographic location, animal origin (where applicable), and disease (where applicable) are shown. All strains with the EC or S prefix were obtained from the Veterinary Laboratories Agency-Weybridge diagnostic laboratory. For EC strains, the last two numbers denote the year the isolate was collected; the S strains were from the Veternary Laboratories Agency-Weybridge reference laboratory collection. Virulence determinants which were successfully amplified by PCR are shown for each strain.

^bPHLS, Public Health Laboratory Service, Colindale, London, United Kingdom.

^cAtypical EHECs do not possess either the γ-intimin or hemolysin A or are not VT positive. Atypical EPECs do not possess either the β, δ, or α intimin or bundle forming pili genes but may possess VT or hemolysin genes.

^disolate from a cattle farm which was the source of an O157 human outbreak.