TABLE 3.

In vivo and in vitro properties of STM mutants^a

Strain	Genotype	ID50 (106)b	% Hagc	Serum resistanced	Tracheal ring bindinge
197N	parental	7 ± 8.7	(100)	73 ± 13	6.68 ± 2.98
PAS334	fhaB::miniTn5	≥6590 ± 5600*	100 ± 0	103 ± 33	7.72 ± 4.03
PAS355	fhaC::miniTn5	≥12400 ± 450**	88 ± 18	75 ± 8	2.36 ± 0.90*
PAS213	fimC::miniTn5	≥8680 ± 7900*	75 ± 0	75 ± 23	0.97 ± 0.45**
PAS356	bvgS::miniTn5	≥10500 ± 2500**	88 ± 18	83 ± 27	0.52 ± 0.18**

^a∗∗, to all values that were significantly different (P < 0.01) from the parental strain using the Student t test. ∗, values that were significantly different (P < 0.05) from the parental strain using the Student's t-test.

^bID₅₀ values were determined as previously described (45). Data are averages and standard deviations. Inequality (≥) refers to the fact that no birds were infected at any dose given. The numeric value shown is the lowest possible ID₅₀ achieveable, i.e., it represents the ID₅₀ value calculated if all animals were infected at a dose one order of magnitude higher than the highest dose employed.

^cHag, hemagglutination. Overnight cultures were tested for their ability to agglutinate guinea pig erythrocytes in plate agglutination assays (16). Logarithms (base 2) of the reciprocal value of the agglutination titers were compared after normalization to that for the parental strain (100%). Values represent averages ± standard deviation for at least two separate experiments.

^dSerum resistance values are the percentage of initial inoculum that survives 1 h at 37°C in 50% naive turkey serum as described in the text. Values represent average ± standard deviations for at least two separate experiments.

^eTracheal ring binding was carried out as described by Temple et al. (45). Values indicate the percentage of initial inoculum bound to embryonic turkey tracheal rings. Values represent averages ± standard deviations for at least two separate experiments performed in triplicate.