TABLE 2.

LD₅₀ values of S. typhimurium strains^a

Bacterial strain	Mutation	Mouse strain	LD50 (CFU)
12023		BALB/c	<10
SL1344		BALB/c	<13
12023		C3H/HeN	4.20 × 103
P11D10	ssaJ::mTn5	BALB/c	1.35 × 106
P11D10	ssaJ::mTn5	C3H/HeN	6.27 × 105
SLD10	ssaJ::mTn5	BALB/c	9.27 × 105

^aGroups of five female BALB/c or C3H/HeN mice were inoculated i.p. with 1:10 dilutions of bacteria suspended in physiological saline. The LD₅₀ values were calculated after 28 days by the method of Reed and Muench (42).