Comparison of CP9 and the cnf1 isogenic mutant CP9cnf1 at 1 to 3 days after inoculation of C3H/HeOuJ or BALB/c mice. (A) Twenty female C3H/HeOuJ mice were inoculated with 1.9 × 107 CFU and sacrificed 1 day later. Organ samples were collected, homogenized, serially diluted, and plated on LB agar. Symbols: ▵, CP9; ▴, CP9cnf1. (B) Fifteen female BALB/c mice were infected with 1.9 × 107 CFU and sacrificed for colony counts 1 day later. Symbols: ▵, CP9; ▴, CP9cnf1. (C) Fifteen female C3H/HeOuJ mice were infected with 1.9 × 107 CFU and sacrificed 2 days later. Symbols: ▵, CP9; ▴, CP9cnf1. (D) Ten female C3H/HeOuJ mice were infected with 1 × 108 CFU and euthanatized 3 days later. Counts of CP9 bacteria were significantly higher than those of CP9cnf1 in the urine and bladders (Student's t test, P < 0.05). Symbols: ▵, CP9; ▴, CP9cnf1. Each point represents one sample. The height of the bar represents the mean for those samples. Urine samples were not obtained from every mouse, and mice that did not become infected were not included in the analysis.