FIG 3.
Lack of a detrimental effect of sse and sagA deletion on the clearance of MGAS315 from skin infection sites and from human blood. (A) Persistence of MGAS315 and the Δsse, ΔsagA, and Δsse ΔsagA mutants at skin infection sites. About 108 CFU of bacteria of each strain was subcutaneously inoculated into groups of 16 6-week-old female C57BL/6J mice. Eight mice from each group were euthanized at 1 h and 24 h after inoculation. Presented are the numbers and median values of the numbers of viable GAS at the skin infection sites. The P values are for 1 h versus 24 h by comparison of each strain by the Mann-Whitney t test. p.i., postinoculation. (B) Growth factors for MGAS315 and its derivative strains in nonimmune blood and serum. The strains were inoculated (∼105 CFU) into 0.5 ml of nonimmune blood or serum in triplicate and incubated for 3 h at 37°C with end-to-end rotation. The growth factor was defined as the ratio of the number of viable CFU of GAS in each sample over the number of CFU in the inoculum. P values were determined by 1-way ANOVA for multiple-comparison analyses (P ≥ 0.1184).