Virulence of a Salmonella typhimuriumOmpD Mutant

DOI: 10.1128/IAI.66.1.387-390.1998

Article Figures & Data

Open in new tab
Download powerpoint
Fig. 1.
Separation of outer membrane fractions of six strains ofS. typhimurium by SDS–10% PAGE. Lane 1, wild-type SL1344 strain χ3339; lane 2, ompC mutant BRD454; lane 3,ompD mutant BRD455; lane 4, ompD mutant SL1344 strain χ8201; lane 5, wild-type UK-1 strain χ3761; lane 6,ompD mutant UK-1 strain χ8202.

Table 1.

Bacterial strains

Table 2.

Adherence to and invasion of Int-407 cells by wild-type,ompD, and invA strains of S. typhimurium

↵a P values are given only when the percent adherence or invasion for a mutant is significantly different from that of its wild-type parent (NS, not significant). The test statistic was calculated from the following equation: t= (y¯₁ −y¯₂)/s [(1/n₁) + (1/n₂)]^1/2.y¯₁ is the mean for percent adherence or percent invasion for wild type; y¯₂ is the mean for percent adherence or percent invasion for each mutant strain;s is the standard deviation; n₁ is the number of samples averaged in y¯₁;n₂ is the number of samples averaged iny¯₂.

Table 3.

Statistical analysis of a colonization study of S. typhimurium SL1344 and an ompD derivative by using a paired difference test^a

Time postinoculation (days)	Tissue	Mean paired difference^b	P value^c
3	Peyer’s patches	−1.1 ± 0.7	NS
	Intestinal wall	−0.6 ± 0.8	NS
	Intestinal contents	0.2 ± 0.3	NS
	Spleen	0.9 ± 2.4	NS
	Liver	−0.2 ± 1.3	NS
6	Peyer’s patches	−1.3 ± 1.0	NS
	Intestinal wall	−1.1 ± 0.6	NS
	Intestinal contents	−1.3 ± 1.3	NS
	Spleen	−0.1 ± 0.1	NS
	Liver	−0.4 ± 0.2	NS

↵a Mice were inoculated with a mixed suspension of bacteria at a ratio of strain χ3339 cells/χ8201 cells of 1.5.
↵b Mean of the paired difference (log₁₀ CFU of strain χ3339 − log₁₀ CFU of strain χ8201) ± the standard deviation.
↵c P values are given only when significant (NS, not significant). The test statistic (t) was calculated as follows: t = (d¯ − μ₀)/s_d/n^1/2 whered is the mean paired difference, μ₀ is the difference of the inoculum (log₁₀ CFU of strain χ3339 − log₁₀ CFU of strain χ8201 [0.18]),s_d is the standard deviation, and nis the sample size (the sample size was four mice, except in a few cases where four mice were tested but results were obtained only for two or three mice).