Figure 6: Effects of SEI on leukocyte-mediated Gram positive bactericidal activity against Staphylococcus aureus. Bactericidal activity is represented by the percentage change (increase or decrease) in the number of colony forming units (CFU) of S. aureus recovered after one hour of exposure to leukocytes derived from the species identified in the absence (black bars) and presence (hatched bars) of 10 μM AI-158 relative to the number of CFU recovered at time zero. The white bar represents the percentage change (increase) in the number of CFU recovered after one hour of incubation in the absence of any leukocytes or inhibitor relative to the number of CFU recovered at time zero. Preliminary studies demonstrated that 10 μM AI-158 had no effect (positive or negative) on the percentage change in recovered CFU after one hour of incubation in the absence of leukocytes (data not shown). Each value is the mean ± SEM of 6 or more measurements. *p <0.001 relative to control (white bar).