Table.

Overview of study isolates

Isolate category	Isolate subcategory			Isolation period	Simpson’s Index of Diversity *	No. isolates tested †	PFGE pattern numbers	No. isolates with PFGE pattern (%)
	Region	Host	Attributes
Recent isolates	Northeast	Cattle	Clinical	2007–2009	0.26 (0.12 – 0.40)‡	64	CU-213	55 (86%)
							CU-843	1 (2%)
							CU-846	1 (2%)
							CU-848	3 (5%)
							CU-849	1 (2%)
							CU-973	3 (5%)
	Northeast	Cattle	Non-clinical	2007–2009	0.06 (0.00 – 0.18) ‡	32	CU-213	31 (97%)
							CU-843	1 (3%)
	Northeast	Farm environment		2007–2009	0.25 (0.08 – 0.42) ‡	45	CU-213	39 (87%)
							CU-839	1 (2%)
							CU-840	2 (4%)
							CU-843	2 (4%)
							CU-874	1 (2%)
Human isolates	Northeast	Human	Clinical	2007–2009	n/a	3	CU-213	3 (100%)
Comparison Isolates	Northwest	Animals	Clinical & Non-clinical	1986–2007	0.43 (0.30 – 0.55) ‡	93	CU-213	70 (75%)
							CU-967	5 (5%)
							CU-968	6 (6%)
							CU-969	8 (9%)
							CU-970	1 (1%)
							CU-971	1 (1%)
							CU-972	1 (1%)
							CU-975	1 (1%)

^*Simpson’s Index of Diversity value for all recent isolates combined: 0.21 (0.12 – 0.31);

^†none of the isolates was resistant to any of the antimicrobial drugs tested, and none of the tested isolates was positive for spvA;

^‡95% Confidence Interval;