Fig 7.

Analysis of bacterial infection in mice and blood survival of WT_M6 and Δap1_M6 strains. A. Number of bacteria obtained after plating dissected and homogenized spleens, lungs, kidneys (total number of cfu) and blood (cfu ml⁻¹) collected 24 h post intraperitoneal infection of mice using 2 × 10⁷ cfu of GAS WT_M6 or Δap1_M6 strains (12 animals per strain, in three independent experiments with four animals each). Each circle represents the number of bacteria recovered in the organ of one mouse, and the average number of bacteria from all mice is indicated by a bar. Differences were statistically significant in all organs (**P < 0.01, U-test). B. Competitive index of GAS WT_M6 versus Δap1_M6 strains. Eight mice (in two independent experiments with four animals each) were infected intraperitoneally with 10⁷ cfu of WT_M6 and 10⁷ cfu of Δap1_M6. After 24 h, bacteria were recovered from the lungs and spleens of sacrificed animals and plated. Wild-type bacteria were discriminated from mutant strains by colony blot analysis using antibodies to rAP1_M6 protein. Each circle represents the ratio between the number of cfu of the two strains in the organ of one mouse, and the average ratio is indicated by a bar. C. Survival of GAS WT_M6 with or without rAP1_M6, of the deletion mutant Δap1_M6, and of the complemented strain Δap1_M6(pAMap1_M6) in whole blood from rabbits. For each strain, the average relative growth rate (cfu at time 5 h divided by cfu at time 0) versus that of wild type (to which we assigned a value of 100) obtained from three different experiments, and its standard deviation, are reported. Significant differences between strains were calculated by Student's t-test, **P < 0.01, *P < 0.05.