FPR2 and infection: However, the numbers of bacteria of the mutant strain were equal in the peritoneum and kidney (Figures 7B, C) or reduced (Figure 7D) in the spleen compared to those of the wild-type S. aureus, indicating that S. aureus depends on the cytolytic PSMs while the neutrophil-activating FPR2-mediated PSM activity is less significant in this type of infection.