The mean phagocytosis (A) and killing (B) percentages (±SD) of S . chromogenes, S. simulans , S. agnetis and S. aureus by murine J774 macrophages. S. simulans was less phagocytosed than S. agnetis (p = 0.014) and S. chromogenes (p < 0.001). S. aureus was less phagocytosed than S. chromogenes (p = 0.020). S. chromogenes differed from other species and was killed more efficiently (p < 0.05). Negative values for killing are due to the growth of staphylococci during saponin treatment.