TABLE 3.

Virulence assessment of mutants deficient in genes with enhanced expression during ECC or growth in blood

Challenge type and strain	Function	Log10 median titer 2 days postchallengera in:				% Survivalc
		Nasal lavage or lungsb		Blood
		Titer	P	Titer	P
Intranasal challenge
T4X		6.1	NA	5.6	NA	10
T4X SP0090-	ABC transporter, permease	4.3	0.003	<3.0	<0.001	100
T4X SP0092-	ABC transporter, substrate binding protein	5.7	0.278	4.6	0.107	10
T4X SP0498-	Endo-β-N-acetylglucosaminidase, putative	5.5	0.026	5.7	0.377	10
T4X SP1021-	hemK; conserved protein	5.7	0.088	4.7	0.163	20
T4X SP1753-	Sodium/dicarboxylate symporter family protein	4.5	0.011	4.3	0.077	10
T4X SP2143-	Conserved hypothetical protein	5.0	0.029	<3.0	<0.001	100
T4X SP2163-	PTS system, IIB component	5.1	0.011	<3.0	<0.001	70
D39X		4.9	NA	7.1	NA	27
D39X SP0090-	ABC transporter, permease protein	4.3	0.119	6.6	0.527	40
D39X SP2143-	Conserved hypothetical protein	4.2	0.111	6.9	0.748	27
D39X SP2163-	PTS system, IIB component	6.2	0.235	7.0	0.852	13
Intratracheal challenge
D39X		8.4	NA	9.0	NA	0
D39X SP0115-	Hypothetical protein	8.4	0.902	9.1	0.535	0
D39X SP0142-	Hypothetical protein	8.6	0.805	9.1	0.710	0
D39X SP0641-	Serine protease	8.3	1.000	9.0	0.620	0
D39X SP1002-	lmb; adhesion lipoprotein	7.2	0.128	9.0	0.620	0
D39X SP1175-	Conserved domain protein	7.5	0.234	8.6	0.181	0
D39X SP1434-	ABC transporter	8.5	0.383	9.2	0.165	0

^aA total of 12 to 20 mice were used to examine each mutant in both challenge models. Statistical analysis was performed by using a Mann-Whitney rank sum test. Mutant titers were compared to the corresponding wild-type titers. Values in bold face indicate a statistically significant difference. NA, not applicable.

^bNasal lavage for intranasal challenge and lungs for intratracheal challenge.

^cThat is, the percent survival 1 week after intranasal challenge or the percent survival 4 days after intratracheal challenge.