FIG 3.

Impact of yraP disruption on in vivo virulence. (A) Competitive indexes of the S. Typhimurium SL1344 parental strain versus the isogenic yraP mutant at 4 days postinfection were determined from the spleens and livers of C57BL/6 mice. Statistical significance was determined using a Mann-Whitney t test (*, P < 0.05; **, P < 0.01). (B) Bacterial burdens per organ of CD1 mice infected intraperitoneally with 3 × 10³ CFU of S. Typhimurium SL1344 and the isogenic yraP mutant. Results were obtained at 3 days postinfection. Statistical significance was calculated using a Mann-Whitney test (*, P < 0.05; NS, not significant). (C) Bacterial burdens per spleen at various time points after intraperitoneal infection of C57BL/6 mice with 5 × 10⁵ CFU of attenuated S. Typhimurium SL3261 and the respective yraP mutant. Bars represent the average burdens calculated from four mice. Statistical significance was calculated using a Mann-Whitney test (*, P < 0.05). (D) Relative total IgG titers to purified OMPs in mouse sera compared to control (noninfected-mouse sera) from days 18 and 28 postinfection with the attenuated S. Typhimurium SL3261 parental stain or isogenic yraP mutant. Bars represent the average titers calculated from four mice per group. (E) Bacterial burdens per organ of RagB6 mice 24 h after intraperitoneal infection with 5 × 10⁵ CFU of attenuated S. Typhimurium strain SL3261 or isogenic yraP mutant. Bars represent the average burdens calculated from four mice. *, P < 0.05; ***, P < 0.001.