TABLE 1.

Numbers of CFU and ST strains in tissues 5 days after oral infection

Dose	Mouse	Cecum		MLN		Spleen
		CFU	STa	CFU	ST	CFU	ST
8 × 107	1	1.0 × 103	NDb	4.8 × 104	5	150	ND
	2	200	ND	6	ND	0
	3	6.5 × 104	ND	1.6 × 103	24	0
8 × 108	1	4.2 × 104	27	4.0 × 103	28	0
	2	8.9 × 104	35	1.0 × 104	26	6.8 × 103	ND
	3	3.0 × 104	35	1.2 × 104	19	0
3 × 109	1	1.3 × 105	30	9.4 × 103	13	2.9 × 103	ND
	2	2.0 × 106	32	4.0 × 104	25	100	ND
	3	5.0 × 104	36	2.5 × 104	22	2.5 × 104	1
8 × 109	1	6.0 × 105	42	1.7 × 104	31	500	ND
	2	3.0 × 105	36	6.0 × 104	28	3.6 × 103	6
	3	6.0 × 105	39	2.8 × 104	27	5.5 × 103	ND

^aNumber of different ST strains in each tissue, calculated by probing colony blots as described in Materials and Methods. 

^bND, not done.