Table 2.

XbaI-PFGE types of S. Infantis isolates on 478 cattle farms.

	PFGE type*
Year	type 1	type 2	type 3	other types **	Total
1985	9			1	10
1986	9	1		2	12
1987	5	1		3	9
1992	2	1		1	4
1993	11			3	14
1994	15	6		7	28
1995	179	12	11	41	243
1996	70	12	7	27	116
1997	11	2	2	3	18
1998	13	2	2	5	22
1999	7	2		1	10
2000	2			1	3
2001	1			1	2
2002				1	1
2003	1			1***	2
	335	39	22	98	494

*Only bands larger than 125 kb of the XbaI profile were regarded. Generally, one PFGE type per farm per year was included. If a farm had several types in the same year, all profiles were included.

**48 different PFGE types.

***A new type not seen previously. Resembles PFGE type 167 (Fig. 2), with two additional bands of 125 and 140 kb.