TABLE 4.

Colonization and invasive properties of S. enterica serovar Dublin and S. enterica serovar Typhimurium vaccine strains and pL408 stability after oral administration to mice

Bacterial straina	Mouse lineageb	Colonization (CFU/5 PP)/invasion (CFU/spleen)c	% flagellin expression4
SL5930	BALB/c	3.5 × 103/1.1 × 102	83
	C3H/HePas	1.1 × 103/9.5 × 101	79
LM408	BALB/c	4.1 × 102/8 × 101	5
	C3H/HePas	9.1 × 102/2.5 × 101	7

^aThe Salmonella strains were given as a single oral dose (10¹⁰ CFU).

^bThe C3H/HePas and BALB/c mouse strains were chosen for their ability to develop antibody responses to type d flagellin after p.o. immunization with S. enterica serovar Dublin vaccine strains.

^cColonization was measured as the number of colonies detected on Luria-novobiocin plates inoculated with five homogenized PP collected 7 days after oral inoculation of the animals with one of the tested Salmonella strains. Similarly, invasion was determined after plating of the spleen homogenates of inoculated mice. Numbers represent the total number of bacteria recovered from five PP (colonization) or the whole spleen (invasion) and are the means for three inoculated female mice.

^dFlagellin expression was measured indirectly by measuring pLS408 stability in the two Salmonella hosts. Colonies recovered from plates inoculated with spleen or PP homogenates were replica plated in ampicillin-containing LB agar plates. Values are percentages of ampicillin-resistant colonies compared to the total number of tested colonies.